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February 01, 2019

  • Date:26TuesdayFebruary 2019

    Chemical and Biological Physics and Organic Chemistry Seminar

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    Time
    11:00 - 12:00
    Title
    The Dynamics of Charged Excitons in Electronically and Morphologically Homogeneous Single-Walled Carbon Nanotubes
    Location
    Helen and Milton A. Kimmelman Building
    LecturerProf Michael J. Therien
    Duke University ‎
    Organizer
    Department of Chemical and Biological Physics
    Contact
    AbstractShow full text abstract about The trion, a three-body charge-exciton bound state, offers u...»
    The trion, a three-body charge-exciton bound state, offers unique opportunities to simultaneously manipulate charge, spin and excitation in one-dimensional single-walled carbon nanotubes (SWNTs) at room temperature. Effective exploitation of trion quasiparticles requires fundamental insight into their creation and decay dynamics. Such knowledge, however, remains elusive for SWNT trion states, due to the electronic and morphological heterogeneity of commonly interrogated SWNT samples, and the fact that transient spectroscopic signals uniquely associated with the trion state have not been identified. Here length-sorted SWNTs and precisely controlled charge carrier-doping densities are used to determine trion dynamics using femtosecond pump-probe spectroscopy. Identification of the trion transient absorptive hallmark enables us to demonstrate that trions (i) derive from a precursor excitonic state, (ii) are produced via migration of excitons to stationary hole-polaron sites, and (iii) decay in a first-order manner. Importantly, under appropriate carrier-doping densities, exciton-to-trion conversion in SWNTs can approach 100% at ambient temperature. We further show that ultrafast pump-probe spectroscopy, coupled with these fundamental insights into trion formation and decay dynamics, enables a straightforward approach for quantitatively evaluating the extent of optically-driven free carrier generation (FCG) in SWNTs: this work provides fundamental new insights into how quantum yields for optically-driven FCG [Φ(Enn → h+ + e−)] in SWNTs may be modulated as functions of the optical excitation energy and medium dielectric strength. Collectively, these findings open up new possibilities for exploiting trions in SWNT optoelectronics, ranging from photovoltaics, photodetectors, to spintronics.
    Lecture
  • Date:26TuesdayFebruary 2019

    A Clockwork Wikipedia: a case study into knowledge and facts in the digital age

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    Time
    11:30 - 11:30
    Location
    Nella and Leon Benoziyo Building for Biological Sciences
    LecturerOmer Benjakob and Rona Aviram
    Omer Benjakob, Cohn Institute for the History and Philosophy of Science and Ideas, Tel Aviv University and Rona Aviram, Department of Biomolecular Sciences, Weizmann Institute of Science
    Organizer
    Department of Plant and Environmental Sciences
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    Lecture
  • Date:26TuesdayFebruary 2019

    Diffusion-Enhanced Photon Inference (DEPI) for accurate retrieval of distance distributions in single-molecule FRET experiments

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    Time
    14:00 - 15:00
    Location
    Helen and Milton A. Kimmelman Building
    LecturerProf. Eitan Lerner
    HUJI
    Organizer
    Department of Chemical and Structural Biology
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    Lecture
  • Date:27WednesdayFebruary 2019

    Diamond quantum technologies: magnetic sensing, hyperpolarization and noise spectroscopy

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    Time
    11:00 - 12:00
    Location
    Perlman Chemical Sciences Building
    LecturerProf. Nir Bar-Gill
    Dept. of Applied Physics, Racah Institute of Physics, HUJI
    Organizer
    Department of Molecular Chemistry and Materials Science
    Contact
    AbstractShow full text abstract about Nitrogen Vacancy (NV) centers in diamond have emerged over t...»
    Nitrogen Vacancy (NV) centers in diamond have emerged over the past few years as well-controlled quantum systems, with promising applications ranging from quantum information science to magnetic sensing.
    In this talk, I will first introduce the NV center system and the experimental methods used for measuring them and controlling their quantum spin dynamics. I will mention the application of magnetic sensing using NVs through the realization of a magnetic microscope [1].
    I will then describe our work on nuclear hyperpolarization, potentially relevant for enhanced MRI contrast, and research into open quantum systems and quantum thermodynamics [2].
    Finally, I will present related control sequences, which can be used to perform optimized quantum noise spectroscopy, allowing for precise characterization of the environment surrounding a quantum sensor [3].
    1. E. FARCHI ET. AL., SPIN 7, 1740015 (2017).
    2. HOVAV, Y., NAYDENOV, B., JELEZKO, F. AND BAR-GILL, N., PHYS. REV. LETT. 120, 6, 060405 (2018)
    3. Y. ROMACH ET. AL., PHYS. REV. APPLIED 11, 014064 (2019).
    Lecture
  • Date:28ThursdayFebruary 2019

    Publishing in Nature Communications

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    Time
    10:00 - 11:00
    Location
    Perlman Chemical Sciences Building
    LecturerDr. Bo Liu
    Associate Editor, Nature Communications
    Organizer
    Department of Molecular Chemistry and Materials Science
    Contact
    AbstractShow full text abstract about In this talk, I will introduce the Nature Communications jou...»
    In this talk, I will introduce the Nature Communications journal, the editorial office in Shanghai, the editorial process and insiders’ view on the Nature Communications.


    Bo joined Nature Communications in March 2017. Following his undergraduate studies in Zhejiang University, China, he obtained his PhD in Physics at National University of Singapore. He then carried out his postdoctoral research at Graphene Research Center in Singapore and University of Washington. He currently handles manuscripts on solar cells and halide perovskite photophysics. Bo is based in the Shanghai office.
    Lecture
  • Date:28ThursdayFebruary 2019

    DLTS defects characterization of process and irradiation induced defects in 4H-SiC

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    Time
    11:00 - 12:00
    Location
    Perlman Chemical Sciences Building
    LecturerProf. Mmantsae Diale
    Dept. of Physics, University of Pretoria
    Organizer
    Department of Molecular Chemistry and Materials Science
    Contact
    AbstractShow full text abstract about 4H-SiC epitaxial layers were irradiated using various radioa...»
    4H-SiC epitaxial layers were irradiated using various radioactive sources and particle accelerators. The electronic properties of induced defects were characterized by means of deep-level transient spectroscopy (DLTS) and Laplace DLTS. This presentation is a review of various observations due to processing various particles used in irradiation of 4H-SiC. From the results it was evident that the same defects were induced by various radiation sources. Irradiation induced the acceptor level of the Z1 center and the donor level of the Z2 center. The concentration of the native defects, which originate from impurities encountered in the growth process increased. DLTS spectra observed after irradiation were exhibited sitting on skewed baselines which in some instances inhibited accurate Laplace-DLTS resolution.
    Lecture
  • Date:28ThursdayFebruary 2019

    "DLTS defects characterization of process and irradiation induced defects in 4H-SiC”

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    Time
    11:00 - 12:00
    Location
    Perlman Chemical Sciences Building
    LecturerProf. Mmantsae Diale
    Dept. Of Physics, University of Pretoria
    Organizer
    Department of Molecular Chemistry and Materials Science
    Contact
    AbstractShow full text abstract about 4H-SiC epitaxial layers were irradiated using various radioa...»
    4H-SiC epitaxial layers were irradiated using various radioactive sources and particle accelerators. The electronic properties of induced defects were characterized by means of deep-level transient spectroscopy (DLTS) and Laplace DLTS. This presentation is a review of various observations due to processing various particles used in irradiation of 4H-SiC. From the results it was evident that the same defects were induced by various radiation sources. Irradiation induced the acceptor level of the Z1 center and the donor level of the Z2 center. The concentration of the native defects, which originate from impurities encountered in the growth process increased. DLTS spectra observed after irradiation were exhibited sitting on skewed baselines which in some instances inhibited accurate Laplace-DLTS resolution.
    Lecture
  • Date:28ThursdayFebruary 2019

    Challenges for physical cosmology after Planck

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    Time
    11:15 - 12:30
    Location
    Edna and K.B. Weissman Building of Physical Sciences
    LecturerProf. Matias Zaldarriaga
    IAS Princeton
    Organizer
    Faculty of Physics
    Contact
    AbstractShow full text abstract about I will discuss the current status of physical cosmology afte...»
    I will discuss the current status of physical cosmology after the latest Cosmic Microwave Background and other measurements. I will discuss the questions that still remain open in the field and how we might go about answering them. I will describe some recent theoretical developments that might contribute useful tools for overcoming some of the challenges that lie ahead.
    Colloquia
  • Date:28ThursdayFebruary 2019

    Paleoclimatic changes and possible implications for the human occupation in South America

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    Time
    13:00 - 14:00
    Location
    Helen and Martin Kimmel Center for Archaeological Science
    LecturerProf Francisco Da Cruz Jr.
    Sao Paulo University
    Organizer
    Academic Educational Research
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    Lecture
  • Date:28ThursdayFebruary 2019

    Larger than life: Formation and function of bone-resorbing osteoclasts

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    Time
    14:00 - 15:00
    Location
    Max and Lillian Candiotty Building
    LecturerProf. Ari Elson
    Organizer
    Department of Immunology and Regenerative Biology
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    Lecture
  • Date:28ThursdayFebruary 2019

    Mn(II) EPR tracks the hydrolysis state and ATP/ADP dependent conformation in yeast Hsp90 chaperone

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    Time
    14:00 - 15:00
    Location
    Perlman Chemical Sciences Building
    LecturerDr. Angeliki Giannoulis
    Department of Chemical and Biological Physics, WIS
    Organizer
    Department of Molecular Chemistry and Materials Science
    Contact
    AbstractShow full text abstract about Hsp90 plays a central role in cell homeostasis by assisting ...»
    Hsp90 plays a central role in cell homeostasis by assisting folding and maturation of many client proteins. In order to perform this chaperoning activity Hsp90 hydrolyzes ATP, which requires Mg(II) as cofactor and the hydrolysis is coupled to large global conformational changes. Hsp90 is homo-dimeric with each monomer consisting of three consecutive domains (CTD, MD, NTD). The ATPase site is found in each of the two NTDs, while the CTDs constitute the dimerization site. X-ray crystallography and FRET have provided insights on the conformational cycle of Hsp90 which involves transition from a nucleotide-free ‘open’ to a nucleotide-bound ‘closed’ conformation by dimerization of the NTDs. However, there are still open questions on whether the chaperone shifts global conformation as a consequence of hydrolysis.
    Here, we investigate the ATPase site and the concomitant conformational changes at various nucleotide-bound states (pre-hydrolysis, intermediate high energy and post- hydrolysis states) in yeast Hsp90 using EPR techniques. To do so, we substituted the Mg(II) cofactor with paramagnetic Mn(II) and performed hyperfine and pulsed dipolar EPR experiments, to probe short and long range interactions, respectively. Specifically, we tracked ATP hydrolysis by exploring the Mn(II) coordination by the nucleotide phosphates using 31P electron nuclear double resonance (ENDOR) spectroscopy. The interaction of the Mn(II) with protein residues in the different hydrolysis states was investigated by 14/15N ELDOR-detected nuclear magnetic resonance (EDNMR). Last, we measured the distance between the two Mn(II) cofactors in each of the monomers using double electron–electron resonance (DEER/PELDOR) spectroscopy. Here, we measured a well-defined Mn(II)-Mn(II) distance of 4.3 nm in the pre-hydrolysis state, which changes both in width and mean distance in the post-hydrolysis state providing experimental evidence to the existence of two different ‘closed’ conformations for the ATP and ADP bound states. Within our approach one can probe both local and global interactions from a single sample via exploitation of intrinsic sites (here Mg(II)->Mn(II)) that can potentially yield new structural insights previously challenging to observe with FRET and EPR using site-specific spin labeling.
    Lecture
  • Date:28ThursdayFebruary 2019

    Pelletron meeting - by invitation only

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    Time
    16:00 - 17:45
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  • Date:03SundayMarch 2019

    I-CORE final meeting -The end of the quantum universe

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    Time
    08:00 - 16:00
    Location
    The David Lopatie Conference Centre
    Chairperson
    Yosef Nir
    Conference
  • Date:03SundayMarch 2019

    Sensitivity Analysis and Uncertainty Quantification in Hydrogeological Modeling

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    Time
    11:00 - 11:00
    Location
    Sussman Family Building for Environmental Sciences
    LecturerAlberto Guadagnini
    Politenico di Milano
    Organizer
    Department of Earth and Planetary Sciences
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    Lecture
  • Date:03SundayMarch 2019

    EMERGING CONCEPTS IN BREAST CANCER

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    Time
    11:00 - 14:00
    Title
    Minerva and Dwek Institute for Cancer Therapy Research workshop
    Location
    Max and Lillian Candiotty Building
    LecturerProf. Stefan Wiemann, Prof. Carlos Caldas, Prof. Sima Lev
    Organizer
    Department of Immunology and Regenerative Biology
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    Lecture
  • Date:04MondayMarch 2019

    IMM Guest seminar- Prof. Benny Chain will lecture about "The T cell receptor repertoire in health and disease."

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    Time
    13:00 - 14:00
    Location
    Wolfson Building for Biological Research
    LecturerProf. Benny Chain
    Division of Infection and Immunity, and Dept. of Computer Science , UCL, London
    Organizer
    Department of Systems Immunology
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    Lecture
  • Date:05TuesdayMarch 2019

    Signaling and Transcriptional Foundations of Human Naïve Pluripotency

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    Time
    09:00 - 10:00
    Location
    Max and Lillian Candiotty Building
    LecturerProf. Jacob Hanna
    Department of Molecular Genetics
    Organizer
    Department of Immunology and Regenerative Biology
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    Lecture
  • Date:05TuesdayMarch 2019

    Adventures of bambusuril chemistry

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    Time
    11:00 - 12:00
    Location
    Helen and Milton A. Kimmelman Building
    LecturerProf. Vladimir Sindelar
    Department of Chemistry & RECETOX Masaryk University
    Organizer
    Department of Molecular Chemistry and Materials Science
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    Lecture
  • Date:05TuesdayMarch 2019

    Biosynthesis and Secretion of Plant Cytokinins by Aphids

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    Time
    11:30 - 11:30
    Location
    Nella and Leon Benoziyo Building for Biological Sciences
    LecturerProf. Georg Jander
    Boyce Thompson Institute (BTI) for Plant Research, Ithaca, NY, USA
    Organizer
    Department of Plant and Environmental Sciences
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    Lecture
  • Date:05TuesdayMarch 2019

    Biosynthesis and Secretion of Plant Cytokinins by Aphids

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    Time
    11:30 - 11:30
    Location
    Nella and Leon Benoziyo Building for Biological Sciences
    LecturerProf. Georg Jander
    Boyce Thompson Institute (BTI) for Plant Research, Ithaca, NY, USA
    Organizer
    Department of Plant and Environmental Sciences
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