DAMICO-DISSERTATION-2014.Pdf
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Review Article: Inhibition of Methanogenic Archaea by Statins As a Targeted Management Strategy for Constipation and Related Disorders
Alimentary Pharmacology and Therapeutics Review article: inhibition of methanogenic archaea by statins as a targeted management strategy for constipation and related disorders K. Gottlieb*, V. Wacher*, J. Sliman* & M. Pimentel† *Synthetic Biologics, Inc., Rockville, SUMMARY MD, USA. † Gastroenterology, Cedars-Sinai Background Medical Center, Los Angeles, CA, USA. Observational studies show a strong association between delayed intestinal transit and the production of methane. Experimental data suggest a direct inhibitory activity of methane on the colonic and ileal smooth muscle and Correspondence to: a possible role for methane as a gasotransmitter. Archaea are the only con- Dr K. Gottlieb, Synthetic Biologics, fi Inc., 9605 Medical Center Drive, rmed biological sources of methane in nature and Methanobrevibacter Rockville, MD 20850, USA. smithii is the predominant methanogen in the human intestine. E-mail: [email protected] Aim To review the biosynthesis and composition of archaeal cell membranes, Publication data archaeal methanogenesis and the mechanism of action of statins in this context. Submitted 8 September 2015 First decision 29 September 2015 Methods Resubmitted 7 October 2015 Narrative review of the literature. Resubmitted 20 October 2015 Accepted 20 October 2015 Results EV Pub Online 11 November 2015 Statins can inhibit archaeal cell membrane biosynthesis without affecting This uncommissioned review article was bacterial numbers as demonstrated in livestock and humans. This opens subject to full peer-review. the possibility of a therapeutic intervention that targets a specific aetiologi- cal factor of constipation while protecting the intestinal microbiome. While it is generally believed that statins inhibit methane production via their effect on cell membrane biosynthesis, mediated by inhibition of the HMG- CoA reductase, there is accumulating evidence for an alternative or addi- tional mechanism of action where statins inhibit methanogenesis directly. -
Experimental and Computational Analysis of Bubble Generation Combining Oscillating Electric Fields and Microfluidics
Experimental and computational analysis of bubble generation combining oscillating electric fields and microfluidics A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy By Anjana Kothandaraman Supervised by: Professor Mohan Edirisinghe And Professor Yiannis Ventikos Department of Mechanical Engineering University College London Torrington Place, London WC1E 7JE United Kingdom December, 2017 1 | P a g e Declaration I, Anjana Kothandaraman, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. -------------------------------------- Anjana Kothandaraman 2 | P a g e Abstract Microbubbles generated by microfluidic techniques have gained substantial interest in various fields such as food engineering, biosensors and the biomedical field. Recently, T-Junction geometries have been utilised for this purpose due to the exquisite control they offer over the processing parameters. However, this only relies on pressure driven flows; therefore bubble size reduction is limited, especially for very viscous solutions. The idea of combining microfluidics with electrohydrodynamics has recently been investigated using DC fields, however corona discharge was recorded at very high voltages with detrimental effects on the bubble size and stability. In order to overcome the aforementioned limitation, a novel set-up to superimpose an AC oscillation on a DC field is presented in this work with the aim of introducing additional parameters such as frequency, AC voltage and waveform type to further control bubble size, capitalising on well documented bubble resonance phenomena and properties. Firstly, the effect of applied AC voltage magnitude and the applied frequency were investigated. -
Lecture 4. Electrokinetics and Electrohydrodynamics
Lecture 4. Electrokinetics and Electrohydrodynamics Electrophoresis Electroosmosis Capillary Electrophoresis (CE) DEP preconcentrator Dielectrophoresis (DEP) AC Electroosmosis Electrophoresis • An ion with charge q in an electric field E moves toward opposite electrode due to Coulombic force. A steady-state speed is reached when the accelerating force equals the frictional force generated by the medium. VDC - - Medium Anode + + Cathode FE = qE FFriction = f ⋅uE = 6πηr ⋅uE q u q u = ⋅ E µ = E = E 6πηr E E 6πηr Electrophoretic mobility is a function of viscosity and charge to radius ratio. Applications of Electrophoresis • Many important biological molecules such as amino acids, peptides, proteins, nucleotides, and nucleic acids, possess ionisable groups (COOH, NH2, phosphates) and, therefore, at any given pH, exist in solution as electically charged species either as cations (+) or anions (-). DNA is negatively charged because the phosphates that form the sugar-phosphate backbone of a DNA molecule have a negative charge. • Depending on the nature of the net charge, the charged particles will migrate either to the cathode or to the anode at different rates. Electrophoresis has been applied to a variety of analytical separation problems. – Amino acids – Peptides, proteins (enzymes, hormones, antibodies) – Nucleic acids (DNA, RNA), nucleotides – Drugs, vitamins, carbohydrates – Inorganic cations and anions Gel Electrophoresis • Gel electrophoresis is a separation technique widely used for the separation of nucleic acids and proteins. The separation depends upon electrophoresis and filtering effect by gel (molecular sieve). Under electric field, charged macromolecules are forced to move through the gel with pores. • Their rates of migration depend on the field strength, size and shape of the molecules, hydrophobicity of the samples, and on the ionic strength, and pH, temperature of the buffer in which the molecules are moving. -
Electrokinetics and Electrohydrodynamics in Microsystems Invited Lecturers
TIME TABLE TIME Monday Tuesday Wednesday Thursday Friday June 22 June 23 June 24 June 25 June 26 9.00 - 9.45 Registration Morgan Mugele Bazant Chen 9.45 - 10.30 Ramos Mugele Bazant Green Chen 11.00 - 11.45 Morgan Bazant Green Chen Ramos 11.45 - 12.30 Mugele Green Chen Ramos Ramos 14.30 - 15.15 Bazant Chen Ramos Morgan 15.15 - 16.00 Green Ramos Morgan Mugele 16.30 - 17.15 Chen Green Mugele Bazant 17.15 - 18.00 Morgan e-mail: [email protected] fax +390432248550 tel. +390432248511 (6lines) 33100 Udine(Italy) -PiazzaGaribaldi18 Palazzo delTorso CISM For furtherinformationpleasecontact: our website,orcanbemaileduponrequest. Information about travel and accommodation is available on web site: e-mail: postmaster[at]daad.de tel. +49(228)882-0 DAAD, Kennedyallee50,53175Bonn support toGermanstudents.Pleasecontact: The Deutscher Akademischer Austausch Dienst (DAAD) offers to applicantsfromcountriesthatsponsorCISM. the institute cannot provide funding. Preference will be given by the head of the department or a supervisor confirming that recommendation of letter a and curriculum applicant's the with by Secretariat CISM to sent be should quests offered board and/or lodging in a reasonably priced hotel. Re centres who are not supported by their own institutions can be research and universitites from participants of number limited A The registrationfeeis600,00Euro. our secretariat. pants. If you need assistance for registration please contact A message of confirmationwill be sent to accepted partici our website: through on-line sent be should forms Application course. the of beginning the before month one least at apply must Applicants ADMISSION ANDACCOMMODATION http://www.daad.de/de/kontakt.html http://www.cism.it orbypost. -
Electrohydrodynamic Settling of Drop in Uniform Electric Field at Low and Moderate Reynolds Numbers
Electrohydrodynamic settling of drop in uniform electric field at low and moderate Reynolds numbers Nalinikanta Behera1, Shubhadeep Mandal2 and Suman Chakraborty1,a 1Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur,West Bengal- 721302, India 2Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, D-37077 G¨ottingen, Germany Dynamics of a liquid drop falling through a quiescent medium of another liquid is investigated in external uniform electric field. The electrohydrodynamics of a drop is governed by inherent deformability of the drop (defined by capillary number), the electric field strength (defined by Masson number) and the surface charge convection (quantified by electric Reynolds number). Surface charge convection generates nonlinearilty in a electrohydrodynamics problem by coupling the electric field and flow field. In Stokes limit, most existing theoretical models either considered weak charge convection or weak electric field to solve the problem. In the present work, gravitational settling of the drop is investigated analytically and numerically in Stokes limit considering significant electric field strength and surface charge convection. Drop deformation accurate upto higher order is calculated analytically in small deformation regime. Our theoretical results show excellent agreement with the numerical and shows improvement over previous theoretical models. For drops falling with moderate Reynolds number, the effect of Masson number on transient drop dynamics is studied for (i) perfect dielectric drop in perfect dielectric medium (ii) leaky dielectric drop in the leaky dielectric medium. For the latter case transient deformation and velocity obtained for significant charge convection is compared with that of absence in charge convection which is the novelty of our study. -
(Ehd) Pumping of Liquid Nitrogen –
ABSTRACT Title of Dissertation: ELECTROHYDRODYNAMICS (EHD) PUMPING OF LIQUID NITROGEN – APPLICATION TO SPOT CRYOGENIC COOLING OF SENSORS AND DETECTORS Mihai Rada, Doctor of Philosophy, 2004 Dissertation directed by: Professor Michael M. Ohadi Department of Mechanical Engineering Superconducting electronics require cryogenic conditions as well as certain conventional electronic applications exhibit better performance at low temperatures. A cryogenic operating environment ensures increased operating speeds and improves the signal-to-noise ratio and the bandwidth of analog devices and sensors, while also ensuring reduced aging effect. Most of these applications require modest power dissipation capabilities while having stricter requirements on the spatial and temporal temperature variations. Controlled surface cooling techniques ensure more stable and uniform temporal and spatial temperature distributions that allow better signal-to-noise ratios for sensors and elimination of hot spots for processors. EHD pumping is a promising technique that could provide pumping and mass flow rate control along the cooled surface. In this work, an ion-drag EHD pump is used to provide the pumping power necessary to ensure the cooling requirements. The present study contributes to two major areas which could provide significant improvement in electronics cooling applications. One direction concerns development of an EHD micropump, which could provide the pumping power for micro-cooling systems capable of providing more efficient and localized cooling. Using a 3M fluid, a micropump with a 50 mm gap between the emitter and collector and a saw-tooth emitter configuration at an applied voltage of about 250 V provided a pumping head of 650 Pa. For a more optimized design a combination of saw tooth emitters and a 3-D solder-bump structure should be used. -
Electrohydrodynamics of Particles and Drops in Strong Electric Fields
UC San Diego UC San Diego Electronic Theses and Dissertations Title Electrohydrodynamics of Particles and Drops in Strong Electric Fields Permalink https://escholarship.org/uc/item/335049s5 Author Das, Debasish Publication Date 2016 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California UNIVERSITY OF CALIFORNIA, SAN DIEGO Electrohydrodynamics of Particles and Drops in Strong Electric Fields A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Engineering Sciences (Mechanical Engineering) by Debasish Das Committee in charge: Professor David Saintillan, Chair Professor Juan C. Lasheras Professor Bo Li Professor J´er´emiePalacci Professor Daniel M. Tartakovsky 2016 Copyright Debasish Das, 2016 All rights reserved. The Dissertation of Debasish Das is approved, and it is ac- ceptable in quality and form for publication on microfilm and electronically: Chair University of California, San Diego 2016 iii EPIGRAPH If you keep proving stuff that others have done, getting confidence, increasing the complexities of your solutions - for the fun of it - then one day you’ll turn around and discover that nobody actually did that one! —Richard P. Feynman iv TABLE OF CONTENTS Signature Page................................... iii Epigraph...................................... iv Table of Contents..................................v List of Figures................................... viii List of Tables....................................x Acknowledgements................................ -
Cell Structure and Function in the Bacteria and Archaea
4 Chapter Preview and Key Concepts 4.1 1.1 DiversityThe Beginnings among theof Microbiology Bacteria and Archaea 1.1. •The BacteriaThe are discovery classified of microorganismsinto several Cell Structure wasmajor dependent phyla. on observations made with 2. theThe microscope Archaea are currently classified into two 2. •major phyla.The emergence of experimental 4.2 Cellscience Shapes provided and Arrangements a means to test long held and Function beliefs and resolve controversies 3. Many bacterial cells have a rod, spherical, or 3. MicroInquiryspiral shape and1: Experimentation are organized into and a specific Scientificellular c arrangement. Inquiry in the Bacteria 4.31.2 AnMicroorganisms Overview to Bacterialand Disease and Transmission Archaeal 4.Cell • StructureEarly epidemiology studies suggested how diseases could be spread and 4. Bacterial and archaeal cells are organized at be controlled the cellular and molecular levels. 5. • Resistance to a disease can come and Archaea 4.4 External Cell Structures from exposure to and recovery from a mild 5.form Pili allowof (or cells a very to attach similar) to surfacesdisease or other cells. 1.3 The Classical Golden Age of Microbiology 6. Flagella provide motility. Our planet has always been in the “Age of Bacteria,” ever since the first 6. (1854-1914) 7. A glycocalyx protects against desiccation, fossils—bacteria of course—were entombed in rocks more than 3 billion 7. • The germ theory was based on the attaches cells to surfaces, and helps observations that different microorganisms years ago. On any possible, reasonable criterion, bacteria are—and always pathogens evade the immune system. have been—the dominant forms of life on Earth. -
Performance Characterization of Electrohydrodynamic Propulsion
Performance Characterization of Electrohydrodynamic Propulsion Devices by Kento Masuyama Submitted to the Department of Aeronautics and Astronautics in partial fulfillment of the requirements for the degree of Master of Science at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY September 2012 © Massachusetts Institute of Technology 2012. All rights reserved. Author.............................................................. Department of Aeronautics and Astronautics August 23, 2012 Certified by. Steven R.H. Barrett Assistant Professor Thesis Supervisor Accepted by . Eytan H. Modiano Professor of Aeronautics and Astronautics Chair, Graduate Program Committee 2 Performance Characterization of Electrohydrodynamic Propulsion Devices by Kento Masuyama Submitted to the Department of Aeronautics and Astronautics on August 23, 2012, in partial fulfillment of the requirements for the degree of Master of Science Abstract Partially ionized fluids can gain net momentum under an electric field, as charged par- ticles undergo momentum-transfer collisions with neutral molecules in a phenomenon termed an ionic wind. Electrohydrodynamic thrusters generate thrust by using two or more electrodes to ionize the ambient fluid and create an electric field. In this thesis, electrohydrodynamic thrusters of single- and dual-stage configurations were tested. Single-stage thrusters refer to a geometry employing one emitter electrode, an air gap of length d, and a collector electrode with large radius of curvature relative to the emitter. Dual-stage thrusters add a collinear intermediate electrode in between the emitter and collector. Single-stage thruster performance was shown to exhibit trends in agreement with the one-dimensional theory under both positive and negative DC excitations. Increasing the gap length requires a higher voltage for thrust onset, gen- erates less thrust per input voltage, generates more thrust per input current, and most importantly generates more thrust per input power. -
Structure of Bacterial and Archaeal Cells
© Jones & Bartlett Learning, LLC. NOT FOR SALE OR DISTRIBUTION 4 CHAPTER PREVIEW 4.1 There Is Tremendous Diversity Structure of Among the Bacteria and Archaea 4.2 Prokaryotes Can Be Distinguished by Their Cell Shape and Arrangements Bacterial and 4.3 An Overview to Bacterial and Archaeal Cell Structure 4.4 External Cell Structures Interact Archaeal Cells with the Environment Investigating the Microbial World 4: Our planet has always been in the “Age of Bacteria,” ever since the The Role of Pili first fossils—bacteria of course—were entombed in rocks more than TexTbook Case 4: An Outbreak of 3 billion years ago. On any possible, reasonable criterion, bacteria Enterobacter cloacae Associated with a Biofilm are—and always have been—the dominant forms of life on Earth. —Paleontologist Stephen J. Gould (1941–2002) 4.5 Most Bacterial and Archaeal Cells Have a Cell Envelope “Double, double toil and trouble; Fire burn, and cauldron bubble” is 4.6 The Cell Cytoplasm Is Packed the refrain repeated several times by the chanting witches in Shakespeare’s with Internal Structures Macbeth (Act IV, Scene 1). This image of a hot, boiling cauldron actu- MiCroinquiry 4: The Prokaryote/ ally describes the environment in which many bacterial, and especially Eukaryote Model archaeal, species happily grow! For example, some species can be iso- lated from hot springs or the hot, acidic mud pits of volcanic vents ( Figure 4.1 ). When the eminent evolutionary biologist and geologist Stephen J. Gould wrote the opening quote of this chapter, he, as well as most micro- biologists at the time, had no idea that embedded in these “bacteria” was another whole domain of organisms. -
Electrohydrodynamics of Compound Droplet in a Microfluidic Confinement Somnath Santra , Sayan Das and Suman Chakraborty † Depa
Electrohydrodynamics of compound droplet in a microfluidic confinement Somnath Santra1, Sayan Das1 and Suman Chakraborty1,† 1Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal - 721302, India The present study deals with the dynamics of a double emulsion confined in a microchannel under the presence of a uniform electric field. Towards investigating the non-trivial electrohydrodynamics of a compound droplet, confined in between two parallel plate electrodes, a phase field approach has been adopted. Under the assumption of negligible fluid inertia and small shape deformation, an asymptotic model is also developed to predict the transient as well as the steady state droplet dynamics in the limiting case of an unbounded suspending medium. The phases involved are either assumed to be perfect dielectric or leaky dielectric. Subsequent investigation shows that shape deformation of either of the interfaces of the droplet increase with rise in the channel confinement for a perfect dielectric system. However, for a leaky dielectric system, the deformation of inner droplet and outer droplet can increase or decrease with the rise in channel confinement depending on the electric properties (conductivity and permittivity) of the system. It is also observed that the presence of inner droplet for a compound droplet suppresses the breakup of the outer droplet. The present study further takes into account the effect of eccentricity of the inner droplet. Depending on the relative magnitude of the permittivity and conductivity of the system, the inner droplet, if eccentrically located, may exhibit a to and fro or a simple translational motion. It is seen that increase in the channel confinement results in a translational motion of the inner droplet thus rendering its motion independent of any electrical properties. -
Comparing Prokaryotic and Eukaryotic Cells
Comparing Prokaryotic and Eukaryotic Cells Classification of prokaryotic cellular features: Variant (or NOT common to all) Cell Wall (multiple barrier support themes) Endospores (heavy-duty life support strategy) Bacterial Flagella (appendages for movement) Gas Vesicles (buoyancy compensation devices) Capsules/Slime Layer (exterior to cell wall) Inclusion Bodies (granules for storage) Pili (conduit for genetic exchange) Cell walls of Bacteria Cell envelope structure E. coli structure of peptidoglycan aka murein Peptidoglycan of a gram-positive bacterium Bond broken by penicillin DAP or Diaminopimelic acid Lysine Overall structure of peptidoglycan Cell walls of gram-positive and gram-negative bacteria Teichoic acids and the overall structure of the gram-positive cell wall Summary diagram of the gram-positive cell wall Cell envelopes of Bacteria Cell envelopes of Bacteria Structure of the lipopolysaccharide of gram-negative Bacteria The gram-negative cell wall N-Acetyltalosaminuronic acid Pseudopeptidoglycan of Archaea Paracrystalline S-layer: A protein jacket for Bacteria & Archaea Formation of the endospore Morphology of the bacterial endospore (a) Terminal (b) Subterminal (c) Central (a) Structure of Dipicolinic Acid & (b) crosslinked with Ca++ Bacterial flagella (a) Polar (aka monotrichous) & (b) Peritrichous Structure of the bacterial flagellum Flagellar Motility: Relationship of flagellar rotation to bacterial movement. Gas Vesicles (a) Anabaena flos-aquae (b) Microcystis sp. Hammer & Stopper Experiment (Before) (After) Model of how the two proteins that make up the gas vesicle, GvpA and GvpC, interact to form a watertight but gas-permeable structure. β-sheet α-helix Bacterial Capsules (a) Acinetobacter sp. (b) Rhizobium trifolii negative stain Storage of PHB Sulfur globules inside the purple sulfur bacterium Isochromatium buderi Magnetotactic bacteria with Fe3O4 (magnetite) particles called magnetosomes EM of Salmonella typhi “Sex” Pili used in bacterial conjugation of E.