234 research outputs found
Electrochemomechanics in Mixed Ionic Electronic Conductors and solid oxide cells
No full textThis thesis presents a model for coupled electrochemomechanics in Mixed Ionic Electronic Conductors (MIEC). A continuum model is formulated to simulate the transport of ionic defects and the stress distribution in the conductor arising from the chemical expansion associated with the defects. First, a finite element formulation of the model is developed and validated with various analytical solutions and comparisons with experimental results. In the third chapter the coupled model is used along with an iterative scheme to simulate the transport characteristics in solid oxide cells with oxygen surface exchange and results are compared with experimental cell operation. The model is used to study the effect of oxygen surface exchange and the bulk diffusion of defects on the performance of solid oxide cell. In the fourth chapter, the transport of ionic defects is studied under spatially varying oxygen surface exchange in solid oxide cells due to the presence of metal current collector. Various defect transport mechanisms (boundary value problem setups) are proposed and studied to identify and explain the influence of metal current collector on oxygen exchange at the electrode film surface.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2022-08-01The student, Rupesh Kumar Mahendran, accepted the attached license on 2020-07-21 at 16:46.The student, Rupesh Kumar Mahendran, submitted this Thesis for approval on 2020-07-21 at 17:01.This Thesis was approved for publication on 2020-07-24 at 10:34.DSpace SAF Submission Ingestion Package generated from Vireo submission #15716 on 2020-10-02 at 15:34:04Made available in DSpace on 2020-10-07T22:44:46Z (GMT). No. of bitstreams: 3
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Previous issue date: 2020-07-24Embargo set by: Seth Robbins for item 116264
Lift date: 2022-10-07T22:44:53Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Onl
Editorial
No full textUshus Journal of Business Management wishes all its readers a Happy New Year!In this final issue of 2016, we bring to you two intellectually stimulating research articles and two enlightening case studies that give us new insights into marketing.India is one of the fastest growing economies and a bright spot in an otherwise gloomy world economy with double-digit growth in many sectors like FMCG, Consumer Durables, Fashion, Passenger cars, etc. In the first article of this issue focuses on consumer durables. Consumer durables market is valued at 12.5 billion US$for the year 2015 (IBEF Report, 2016). In the consumer durablemarket the key element is trust towards a brand or a reseller. Keeping this in mindthis research focuses on the trust factor in selling of the non-essential consumer durable products like‘cosmetics.' The author, Suhan, has utilized the path coefficient threshold values to measure between indicators namely, cause purview and emotional benefits, cause consequential and trust, cause rubric and trust, cause span and emotional benefits, emotional benefits and trust, functional benefits and trust, ability and trust, benevolence and trust. Therefore the corporates need to make a moderate effect model to substantial effect by strengthening cause campaigns like the fight against animal testing, support community trade, defend human rights, activate self-esteem and protect the planet by taking environmental issues
Transcriptional responses of Hypericum perforatum cells to Agrobacterium tumefaciens and differential gene expression in dark glands
No full text26 p.-6 fig.-1 tab.-1 fig supl.Hypericum perforatum L. (St. John’s wort) is a well-known medicinal plant that possesses secondary metabolites with beneficial pharmacological properties. However, improvement in the production of secondary metabolites via genetic manipulation is a challenging task as H. perforatum remains recalcitrant to Agrobacterium tumefaciens-mediated transformation. Here, the transcripts of key genes involved in several plant defence responses (secondary metabolites, RNA silencing, reactive oxygen species (ROS) and specific defence genes) were investigated in H. perforatum suspension cells inoculated with A. tumefaciens by quantitative real-time PCR. Results indicated that key genes from the xanthone, hypericin and melatonin biosynthesis pathways, the ROS-detoxification enzyme HpAOX, as well as the defence genes Hyp-1 and HpPGIP, were all upregulated to rapidly respond to A. tumefaciens elicitation in H. perforatum. By contrast, expression levels of genes involved in hyperforin and flavonoid biosynthesis pathways were markedly downregulated upon A. tumefaciens elicitation. In addition, we compared the expression patterns of key genes in H. perforatum leaf tissues with and without dark glands, a major site of secondary metabolite production. Overall, we provide evidence for the upregulation of several phenylpropanoid pathway genes in response to elicitation by Agrobacterium, suggesting that production of secondary metabolites could modulate H. perforatum recalcitrance to A. tumefaciens-mediated transformation.The author acknowledges the financial support provided by the Fundação para a Ciência e a Tecnologia (FCT) project (PTDC/AGR-GPL/119211/2010), to G.F., grant
UID/BIA/04050/2013 (POCI-01-0145FEDER-007569), PhD grant (SFRH/BD/52561/2014), under the Doctoral Programme “Agricultural Production Chains – from fork to farm” (PD/00122/2012) to A.C.P., and by Ministry of Economy and Competitiveness of Spain (grant BIO2016-75619-R [AEI/FEDER, UE]) to F.T.Peer reviewe
DNA Gyrase And Topo NM From Mycobacteria : Insights into Mechanism And Drug Action
No full textMaintenance of a topological homeostasis by introduction and removal of the supercoils to
relieve excessive strain on the DNA is a hallmark of topoisomerase function in the cell. The requirement of the topoisomerases during DNA transaction processes marks a ubiquitous presence of the enzymes in all the life forms. Different reactions carried out by the enzymes include relaxation of positive and negative supercoils required majorly during DNA replication and transcription, decatenation at the end of DNA replication to separate the daughter chromosomes and removal of lethal knots generated in the circular chromosome. In eubacteria, the enzymes introduce negative supercoils to facilitate easier strand separation for DNA
transaction processes. However, in thermophiles, a different enzyme maintains the genome in a positively supercoiled form to protect from denaturation by excessive heat. These varied functions are carried out by different topoisomerases. Therefore, each organism maintains a minimum required set of the enzymes and the absence of a certain enzyme may be compensated for by topoisomerases with dual functions. For example, Mycobacterium tuberculosis and many
other slow growing mycobacteria do not possess topoisomerase IV or its homologs. In these organisms, the DNA gyrase is suggested to carry out both negative supercoiling and decatenation reactions. Therefore, the mycobacterial DNA gyrase must be able to manage between both the functions in vivo. In contrast, Mycobacterium smegmatis and few other mycobacteria contain an additional type II topoisomerase which does not resemble any known type II enzyme but could catalyze relaxation and decatenation reactions. Importantly, the enzyme displays a unique ability to introduce limited positive supercoils and may have certain functions inside the cell which remains to be studied. Owing to the indispensability for bacterial survival topoisomerases present themselves as important drug targets. A large number of inhibitors have been found to inhibit the
enzyme and thereby killing the bacterial. Among these, quinolones are successfully being used as broad spectrum antibacterial drugs. Although the commonly used quinolones inhibit many bacterial pathogens, a reduced susceptibility is exhibited by some of the pathogens e.g. Mycobacterium tuberculosis. To circumvent the lower efficacy of existing drugs, new and modified quinolones have been developed which are highly effective against mycobacteria. The difference in the susceptibility may be conferred by a difference in the chemical property of the
drug and the interacting residues present in the enzyme.
In the present thesis efforts have been made to understand the mechanism of the type II
topoisomerases from mycobacteria and drug action on these enzymes. The thesis is divided into four chapters. In Chapter I of the thesis an introduction is provided on the topoisomerases, their classification and different reactions catalyzed by these enzymes. As the work in present thesis
has been carried out with type II topoisomerases, introduction of type II enzymes, their structure and mechanisms is elaborated. DNA gyrase, its mechanism of reaction and in vitro and in vivo
functions are explained in great detail. DNA gyrase and topoisomerase IV are targeted by a range of different inhibitors. These different classes of inhibitors and their mechanism of action are described. Finally, the mechanism of mycobacterial DNA gyrase with structural information and
the current understanding of quinolone action on the enzyme are explained. The chapter ends
with the objective of the study in the present thesis. In chapter II, the studies are aimed at understanding the molecular basis for decatenation carried out by mycobacterial DNA gyrase.
Previous work from the laboratory showed that the enzyme can carry out decatenation more
efficiently than its homolog from E. coli. It was shown that the mycobacterial enzyme binds two DNA molecules in trans in a length dependent manner. The ability to bind the second DNA is conferred upon the holoenzyme by ATPase subunit (GyrB) subunit which alone can bind DNA. Similar studies using topo IV from E. coli, the strongest known decatenase showed binding of two DNA molecules and the second DNA binding by ATPase (ParE) subunit. However, GyrB subunit from E. coli DNA gyrase, a weaker decatenase, does not bind second DNA molecule efficiently. The results provide a general mechanism for decatenation by type II enzymes in which efficient binding of second DNA is important.
In Chapter III, studies have been carried out using topo NM, an atypical type II topoisomerase from Mycobacterium smegmatis. The enzyme has been characterized previously in the laboratory. In addition to efficient decatenation and relaxation, the enzyme exhibits a unique ability to introduce positive supercoils into the DNA. As demonstrated for the mycobacterial
DNA gyrase and topo IV in the Chapter II, the ATPase subunit (Topo N) of topo NM, binds
second DNA efficiently. The binding of both gate and transport segments increases with the length of the DNA. Binding of two DNA molecules by the holoenzyme appears to be a
cumulative effect of DNA binding to individual subunits. In the absence of any inhibitor, the enzyme accumulates cleaved DNA products with shorter DNA but not with larger DNA. The cleavage of the shorter DNA is supported only in the presence of Mg2+ and Mn2+. Another important property of the enzyme is to introduce positive supercoils which appears to be due to its efficient utilization of ATP and a high rate of reaction.
Chapter IV deals with the interaction of mycobacterial gyrase with fluoroquinolones (FQs). Although DNA gyrase is the sole target of the FQs in M. tuberculosis, the lower susceptibility to commonly used FQs have led to the studies to find out more effective quinolones. Previous studies from the laboratory showed a lower susceptibility of the mycobacterial gyrase to ciprofloxacin, but moxifloxacin could inhibit the enzyme efficiently. The better inhibition by
moxifloxacin appears to be due to efficient trapping of the enzyme-DNA covalent complex. Both ciprofloxacin and moxifloxacin bind the DNA gyrase from mycobacteria, E. coli and E. coli topo IV, independent of DNA. The extent of binding also correlates with the inhibition potential of the drug against a given enzyme. A general model of quinolone enzyme interaction is provided wherein the quinolones are shown to interact with GyrA subunit or holoenzyme or the enzyme-
DNA complex which would finally result in the trapping of the covalent complex
Physiological, subjective and postural loads in passenger train wagon cleaning using a conventional and redesigned cleaning tool
No full textMethods: In this study, cleaning process was studied and analyzed with special reference to cleaning tools. A group of 13 professional cleaners participated in this study. While they performed their normal tasks, their oxygen consumption, heart rate, rating of perceived exertion and postural data were obtained. The perceived exertion during cleaning task using the "redesigned cleaning tool" was less than that of the "conventional cleaning tool". The oxygen consumption when cleaning with the redesigned tool (mean 0.841/m, SD +/- 0.17) was significantly less (p < 0.05) compared to the conventional cleaning tool (mean 0.941/m, SD +/- 0. 18). Heart rate was also found significantly lower using redesigned cleaning tool (mean 101 bpm, SD +/- 11. 10) compared to that of conventional cleaning tool (mean 105 bpm, SD +/- 12.59) (p < 0.05). Using redesigned cleaning tool the trunk postural load was also found significantly less than that of conventional cleaning tool (p < 0.05). It is concluded that redesigned cleaning tool allowed cleaners to maintain more upright posture when cleaning, which reduced biomechanical load. Relevance for Industry: There is need to develop ergonomic criteria or recommendation to enable manufacturers of cleaning equipment to specify and evaluate usability qualities when formulating user requirements for new cleaning tools.</p
'My store my brand' - a critical review of online and offline private label brands in India
No full textSoxhlet Extraction of Spirogyra sp. as an Energy Source and Physicochemical Characterization of Produced Biodiesel
No full textDue to industrialization demand of energy is increasing and hence to meet the demand without any compromise in growth and development, alternative source of energy needs to be found. The best alternative source is biofuels which are extracted from organic compounds. Algae are aquatic organisms almost available in every type of water bodies and considered as potential candidates for biodiesel productions at large scale. In present study, an experimental set –up was designed to produce algal oil through transesterification process. The Soxhlet extraction method is employed as an oil extraction method. The solvent utilized for oil extraction method is n-hexane, petroleum ether and mixture of both solvents to extract the algal oil. Also the oil extracted from the algae is characterized to identify the suitability of algal biodiesel as a potential biofuel for internal combustion (IC) engine. The characterization revealed that physicochemical properties of obtained biodiesel were in permissible range in comparison with standard diesel fuel
'My store my brand' - a critical review of online and offline private label brands in India
No full textA Study of Consumers' Attitude Towards Online Private Label Brands Using the Tri - Component Model
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