102 research outputs found
The Effect of Goal Alignment, Commitment to Networking and Decision-Making on Supply Chain Effectiveness: An Empirical Study
Supply chain management as a phenomenon and research into the supply chain field have been increasing over the past few decades. The supply chain is a management philosophy that includes planning, sourcing, manufacturing and transforming raw materials into finished goods and services and delivering these in damage-free condition to customers through various intermediaries at the correct time, cost and place. However, in modern supply chain management, there is a lack of coordination between functional departments, which affects supply chain performance. Therefore, measuring supply chain performance is the first step towards its strategic improvement
Mega-project engineering-management processes: pre-planning phase evaluation for construction and mining
Mega-projects internationally continue to experience time and cost overruns. Addressing the pre-planning phase has been assessed as a key requirement. This research-project presents two KSA mega-project resources case-studies towards an evaluation of the management-processes applied at the preplanning, design, construction and design phases to clarify procedure and recommend improvement. Findings note the impact of Stage-Gate Process, Gate-keeper approval, and scope-change processes. Recommendations for a best practice stakeholder guide are developed towards best practice
High throughput determination of relevant physicochemical parameters in the drug discovery and HPLC processes. Microfluidic devices
[eng] Determining the acidity (pKa) and lipophilicity (log Po/w) of organic compounds is fundamental in analytical chemistry fields, with potential relevance in drug development, material science, analytical separation, and environmental research. In the first part of the thesis, a high-throughput internal standard capillary electrophoresis (IS- CE) method was established to determine the pKa of ISs at different concentrations of methanol and acetonitrile from 0 to 90% (v/v). The acid and base scales of methanol-water mixtures and acetonitrile-water mixtures were properly anchored to the potentiometrically obtained pKa values of reference compounds to get absolute pKa scales. As a consequence, a set of 46 acid- base compounds with changing structures were proposed as internal standards for consistent pKa measurements in methanol-water and acetonitrile-water mixtures buffers using capillary electrophoresis. The determined ISs reference set facilitates the determination of analytes pKa and measurement of buffer pH in the range 4-11.5 (in water) for any methanol-water and acetonitrile-water composition. Secondly, to prove its feasibility, the IS-CE approach was successfully used to determine the aqueous pKa in methanol-aqueous buffer compositions up to 40% of methanol in volume. The Yasuda-Shedlovsky extrapolation method was utilized to determine seven drugs of different chemical nature with intrinsic water solubilities lower than 10−6 M. The results were successfully compared to literature ones obtained by other approaches. It is concluded then that the IS-CE methodolgy permits the measurement of aqueous pKa values using lower ratios of methanol than the classical method, becoming then more accurate in the extrapolation procedure than other reference methods. Finally, since methanol-water and acetonitrile-water mixtures are solvents of interest in liquid chromatographic separations because of their use as the mobile phase, the IS-CE method was also applied to measure the pKa of eight organic bases in methanol-water and acetonitrile-water mixtures (0-90%,v/v), which are usually used as test compounds in HPLC column evaluation. In the second part of the thesis, a new approach based on microfluidics was developed to determine the octanol-water partition. As a first step, a design with a perpendicular configuration of the channels was developed using direct 3D printed microfluidics. A gravitational perfusion system was implemented to create a spontaneous flow within the octanol and water channels without need for external pump. The movement of octanol and water phases was successfully validated using fluorescent dyes. After that, the intensity of the fluorescent dye was used to evaluate the partition dynamics in static and dynamic conditions. The results prove that the proposed design with this microfluidic methodology allows the evaluation of molecule partition, achieving high efficiency partition and reaching the equilibrium of O/W partition faster than conventional techniques. Later, the design was adapted to a parallel configuration of the channels to be compatible with up-scalable manufacturing techniques and parallelize it for up to 56 simultaneous determinations in a single platform. Finally, both the perpendicular and parallel designs were validated using several drugs with well standardize log Po/w values that cover a wide range of lipophilicity. The microfluidic device was coupled with HPLC to determine their partition coefficients from the peak areas of the compounds in octanol and in water after partition. Good agreement with the literature values was achieved, showing the capability of microfluidic chips for precise and accurate prediction of the partition coefficient. Finally, the progress of a cost-effective and consistent method for predicting partition coefficient via microfluidic chips demonstrated a great advancement in the field of analytical chemistry, with powerful applications in drug discovery and other related fields. The results gotten from this investigation offer an establishment for additional research and advance of this approach.[cat] La determinació de l'acidesa (pKa) i de la lipofilicitat (log Po/w) dels compostos orgànics és fonamental en els camps de la química analítica, amb rellevància potencial en el desenvolupament de fàrmacs, la ciència dels materials, la separació analítica i la investigació ambiental.
En la primera part de la tesi s’estableix un mètode d'electroforesi capil·lar estàndard interna’'alt rendiment (IS-CE) per determinar el pKa de’'analit àcid-base en mescles d'aigua amb solvents orgànics. En aquest treball es va establir un mètode d'electroforesi capil·lar estàndard d'alt rendiment (IS-CE) per determinar el pKaa dels IS a diferents concentracions de metanol i acetonitril del 0 al 90% (v/v).
En segon lloc, per demostrar la seva viabilitat, L'enfocament IS-CE es va utilitzar amb èxit per determinar el pKa aquós en composicions tampó aquoses de metanol fins a un 40% del volum de metanol. El mètode d'extrapolació De Yasuda-Shedlov es va utilitzar per determinar set fàrmacs de diferent naturalesa química amb solubilitats d'aigua intrínseques inferiors a 10-6 M.
Aplicat el mètode IS-CE per mesurar el pKa de vuit bases orgàniques en mescles de metanol- aigua (0 -90%, v/v) i d’acetonitril-aigua, que s’utilitzen habitualment en l'avaluació de columnes de HPLC.
A la segona part de la tesi, es va desenvolupar un nou mètode basat en la microfluídica per determinar la partició octanol-aigua.
Com a primer pas, es va desenvolupar un disseny amb una configuració perpendicular dels canals mitjançant microfluídica impresa En 3d Directa. Es va implementar un sistema de perfusió per gravetat per crear flux espontani dins dels canals d'octanol i aigua sense necessitat de bombament extern. El moviment de les fases d'octanol i aigua es va validar amb èxit mitjançant colorants fluorescents. Després d'això, es va utilitzar la intensitat del colorant fluorescent per avaluar la dinàmica de partició en condicions estàtiques i dinàmiques.
Posteriorment, el disseny es va adaptar a una configuració paral·lela dels canals per ser compatible amb tècniques de manufacturar up-scalable i parallelitzar-lo fins a 56 determinacions simultànies en una sola plataforma. Finalment, tant els dissenys perpendiculars com els paral·lels es van validar utilitzant diversos fàrmacs amb valors log Po/w de registre ben estandarditzats que cobreixen una àmplia gamma de lipofilicitat.
El dispositiu microfluídic es va acoblar amb HPLC per determinar els seus coeficients de partició a partir de les àrees dels pics d’HPLC del compostos en octanol i en aigua després de la partició. Es va aconseguir un bon acord amb els valors de la literatura, mostrant la capacitat dels xips microfluídics per a una predicció precisa del coeficient de partició
Skeletal Muscle Myopathy Mutations in Tropomyosin Gene TPM3 affect Thin Filament Transitions between the Inactive and Active States
Understanding the influence of culture and situational factors on the attitudes and behaviours of employees and managers within an international joint venture.
International joint ventures (IJVs) are important actors in the globalised economy offering a range of business opportunities from market entry to knowledge transfer. However, the success of IJVs is by no means guaranteed. Indeed, many perform badly or fail altogether. Why they fail has already attracted much scholarly interest although most previous research has focused on financial and operational aspects of IJV performance. This research examines IJV performance through the lens of national culture with the aim of developing an insightful understanding of how cultural differences can influence performance and present additional challenges. The thesis addresses research questions about how our understanding of IJV performance can be clarified by identifying the ultimate and proximate factors contributing to IJV performance; the consequences of cultural distance for IJVs; and what senior IJV management can do to minimise the risk of failure when there is great cultural distance between the two partners. The research comprised a single case study of an IJV between an American and Saudi corporation. The setting was an industrial complex in Saudi Arabia. The methodology was predominantly qualitative with data collected from 40 semi-structured interviews, field observations and documentation. Thematic and frame analysis was applied to the data. There is already an extensive literature pertaining to IJV performance and national culture at both the theoretical level and in empirical studies. That literature is reviewed to deduce an initial framework of ultimate and proximate factors influencing IJV performance with the aim of developing that framework in the light of later empirical case study data. National culture is initially proposed as the ultimate factor contributing to attitudes and behaviours within the case study IJV while trust, commitment and communication are proposed as proximate factors. The empirical data analysis, however, revealed that additional important situational and self-interested factors were contributing to the attitudes and behaviours of employees working in the case study IJV. These additional factors included the role of cultural training, cultural intelligence, biculturalism and multiculturalism, adaptability, religious tolerance and perceptions of inequity – and in particular the tendency of interviewees on both sides of the cultural differences to frame the other side in negative and blaming ways. Regarding national culture, cultural distance - particularly along the Individualist/Collectivist dimension - was found to be presenting many challenges to the case study IJV managers and employees. The thesis concludes by proposing a set of recommendations for senior management who are planning to establish, or to improve the performance of, a high cultural contrast IJV
Study of isotherm and kinetic models of lanthanum adsorption on activated carbon loaded with recently synthesized Schiff’s base
AbstractA new effective adsorbent was developed for a selective extraction and determination of lanthanum from aqueous media by use of inductively coupled plasma-optical emission spectrometry. The new adsorbent was based on activated carbon modified with Schiff’s base derived from diethylenetriamine and 3,4-dihydroxybenzaldehyde (AC-DETADHBA). Isotherm and kinetic models were systematically investigated to evaluate the analytical potential of the AC-DETADHBA phase toward La(III) by employing a batch adsorption technique. Surface properties of AC-DETADHBA were characterized by Fourier transform infrared spectrometry. The maximum static adsorption capacity was determined to be 144.80mgg−1 at pH 6, providing that the adsorption capacity of La(III) was improved by 61.79% with the AC-DETADHBA phase as compared to the carboxylic acid derivative of activated carbon after only 1h contact time. Adsorption isotherm results demonstrated that the adsorption process was mainly monolayer on a homogeneous adsorbent surface, confirming the validity of Langmuir adsorption isotherm model. Data obtained from kinetic models study indicated that the adsorption of La(III) onto the AC-DETADHBA phase obeyed a pseudo second-order kinetic model. In addition, results of thermodynamic investigation also revealed that the adsorption mechanism of AC-DETADHBA toward La(III) is a general spontaneous process and favorable. The effect of several coexisting metal ions displayed that the recovery of La(III) was not affected by the medium composition containing either individual or mixed metals. Finally, the newly proposed method gave satisfactory results for the determination of La(III) in environmental water samples
Determination of the aqueous pKa of very insoluble drugs by capillary electrophoresis: Internal standards for methanol-water extrapolation
A fast determination of acidity constants (pKa) of very insoluble drugs has become a necessity in drug discovery process because it often produces molecules that are highly lipophilic and sparingly soluble in water. In this work the high throughput internal standard capillary electrophoresis (IS-CE) method has been adapted to the determination of pKa of water insoluble compounds by measurement in methanol/aqueous buffer mixtures. For this purpose, the reference pKa values for a set of 46 acid-base compounds of varied structure (internal standards) have been established in methanol-water mixtures at several solvent composition levels (with a maximum of 40% methanol). The IS-CE method has been successfully applied to seven test drugs of different chemical nature with intrinsic solubilities lower than 10-6 M. pKa values have been determined at different methanol/aqueous buffer compositions and afterwards Yasuda-Shedlovsky extrapolation method has been applied to obtain the aqueous pKa. The obtained results have successfully been compared to literature ones obtained by other methods. It is concluded that the IS-CE method allows the determination of aqueous pKa values using low proportions of methanol, becoming then more accurate in the extrapolation procedure than other reference methods
Deep Learning for Semi-Automated Brain Claustrum Segmentation on Magnetic Resonance (MR) Images
Title from PDF of title page viewed June 18, 2018Thesis advisor: Yugyung LeeVitaIncludes bibliographical references (pages 73-78)Thesis (M.S.)--School of Computing and Engineering. University of Missouri--Kansas City, 2018In recent years, Deep Learning (DL) has shown promising results with regard to
conducting AI tasks such as computer vision and speech recognition. Specifically, DL
demonstrated the state-of-the-art in computer vision tasks including image
classification, segmentation, localization, and annotation. Convolutional Neural
Network (CNN) models in DL have been applied to prevention, detection, and
diagnosis in predictive medicine. Image segmentation plays a significant role in
predictive medicine. However, there are huge challenges when performing DL-based
automatic segmentation due to the nature of medical images such as heterogeneous
modalities and formats, the very limited labeled training data, and the high-class
imbalance in the labeled data. Furthermore, automatic segmentation becomes a
challenging task, especially for Magnetic Resonance Images (MRI). In reality, it is a
time- consuming procedure that requires trained biomedical experts to manually
segment or annotate such MRI datasets. The need for automated segmentation or
annotation is what motivates our work.
In this thesis, we propose a semi-automated approach that aims to segment the
claustrum in brain MRI images. We recognize that the claustrum is an information
hub of human brains and can be used to find significant patterns from the
segmentations. We applied a 2-Dimensional CNN model called U-net to segment the
human brain dataset comprising 30 manually annotated subjects provided to us by
the Department of Psychiatry at the University of Missouri-Kansas City. Our approach
consisted of the following steps: (1) preprocessing, including converting, the data into
Digital Imaging and Communications in Medicine (DICOM), re-sampling and selecting
the claustrum slices, and applying an ROI selection; (2) building the claustrum model;
(3) automatic segmentation; and (4) evaluation and validation. For the model
validation, we used the cross-validation technique with n = 5. We administered the
Dice coefficient index to evaluate the results and we achieved a Dice score of
approximately 70%. A domain expert also evaluated the results.Introduction -- Background -- Related work -- Proposed solutions -- Proposed model application -- Conclusion and future wor
Surfactant Modified/Mediated Thin-Layer Chromatographic Systems for the Analysis of Amino Acids
This review incorporates a large number of chromatographic systems modified by the surfactants. A large number of solvent systems and stationary phases are summarized in this paper. Three different kinds of surfactants (anionic, cationic, and nonionic) are used as modifiers for stationary phases as well as solvent systems. Surfactants are used at all the three different concentration levels (below, above, and at critical micelle concentration) where surfactants behave differently. Modifications of both stationary phases and solvent systems by surfactants produced a new generation of chromatographic systems. Microemulsion solvent systems are also incorporated in this paper. Microemulsion thin-layer chromatography is a new approach in the field of chromatography
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