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פברואר 01, 2019
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Date:26שלישיפברואר 2019הרצאה
Chemical and Biological Physics and Organic Chemistry Seminar
More information שעה 11:00 - 12:00כותרת The Dynamics of Charged Excitons in Electronically and Morphologically Homogeneous Single-Walled Carbon Nanotubesמיקום בניין הלן ומילטון קימלמןמרצה Prof Michael J. Therien
Duke University מארגן המחלקה לפיזיקה כימית וביולוגיתצרו קשר תקציר Show 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. -
Date:26שלישיפברואר 2019הרצאה
A Clockwork Wikipedia: a case study into knowledge and facts in the digital age
More information שעה 11:30 - 11:30מיקום בניין לביוכימיה על שם נלה וליאון בנוזיומרצה Omer 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 Scienceמארגן המחלקה למדעי הצמח והסביבהצרו קשר -
Date:26שלישיפברואר 2019הרצאה
Diffusion-Enhanced Photon Inference (DEPI) for accurate retrieval of distance distributions in single-molecule FRET experiments
More information שעה 14:00 - 15:00מיקום בניין הלן ומילטון קימלמןמרצה Prof. Eitan Lerner
HUJIמארגן המחלקה לביולוגיה מבנית וכימיתצרו קשר -
Date:27רביעיפברואר 2019הרצאה
Diamond quantum technologies: magnetic sensing, hyperpolarization and noise spectroscopy
More information שעה 11:00 - 12:00מיקום בניין פרלמן למדעי הכימיהמרצה Prof. Nir Bar-Gill
Dept. of Applied Physics, Racah Institute of Physics, HUJIמארגן המחלקה לכימיה מולקולרית ולמדע חומריםצרו קשר תקציר Show 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). -
Date:28חמישיפברואר 2019הרצאה
Publishing in Nature Communications
More information שעה 10:00 - 11:00מיקום בניין פרלמן למדעי הכימיהמרצה Dr. Bo Liu
Associate Editor, Nature Communicationsמארגן המחלקה לכימיה מולקולרית ולמדע חומריםצרו קשר תקציר Show 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.
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Date:28חמישיפברואר 2019הרצאה
DLTS defects characterization of process and irradiation induced defects in 4H-SiC
More information שעה 11:00 - 12:00מיקום בניין פרלמן למדעי הכימיהמרצה Prof. Mmantsae Diale
Dept. of Physics, University of Pretoriaמארגן המחלקה לכימיה מולקולרית ולמדע חומריםצרו קשר תקציר Show 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. -
Date:28חמישיפברואר 2019הרצאה
"DLTS defects characterization of process and irradiation induced defects in 4H-SiC”
More information שעה 11:00 - 12:00מיקום בניין פרלמן למדעי הכימיהמרצה Prof. Mmantsae Diale
Dept. Of Physics, University of Pretoriaמארגן המחלקה לכימיה מולקולרית ולמדע חומריםצרו קשר תקציר Show 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. -
Date:28חמישיפברואר 2019סימפוזיונים
Challenges for physical cosmology after Planck
More information שעה 11:15 - 12:30מיקום בניין הפיזיקה ע"ש עדנה וק.ב. וייסמןמרצה Prof. Matias Zaldarriaga
IAS Princetonמארגן הפקולטה לפיזיקהצרו קשר תקציר Show 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.
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Date:28חמישיפברואר 2019הרצאה
Paleoclimatic changes and possible implications for the human occupation in South America
More information שעה 13:00 - 14:00מיקום מרכז הלן ומרטין קימל למדעי הארכיאולוגיהמרצה Prof Francisco Da Cruz Jr.
Sao Paulo Universityמארגן Academic Educational Researchצרו קשר -
Date:28חמישיפברואר 2019הרצאה
Larger than life: Formation and function of bone-resorbing osteoclasts
More information שעה 14:00 - 15:00מיקום בניין ע"ש מקס ולילאן קנדיוטימרצה Prof. Ari Elson מארגן המחלקה לאימונולוגיה ורגנרציה ביולוגיתצרו קשר -
Date:28חמישיפברואר 2019הרצאה
Mn(II) EPR tracks the hydrolysis state and ATP/ADP dependent conformation in yeast Hsp90 chaperone
More information שעה 14:00 - 15:00מיקום בניין פרלמן למדעי הכימיהמרצה Dr. Angeliki Giannoulis
Department of Chemical and Biological Physics, WISמארגן המחלקה לכימיה מולקולרית ולמדע חומריםצרו קשר תקציר Show 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.
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Date:28חמישיפברואר 2019הרצאה
Pelletron meeting - by invitation only
More information שעה 16:00 - 17:45צרו קשר -
Date:03ראשוןמרץ 2019כנסים
I-CORE final meeting -The end of the quantum universe
More information שעה 08:00 - 16:00מיקום מרכז כנסים על-שם דויד לופאטייושב ראש Yosef Nir -
Date:03ראשוןמרץ 2019הרצאה
Sensitivity Analysis and Uncertainty Quantification in Hydrogeological Modeling
More information שעה 11:00 - 11:00מיקום בניין משפחת זוסמןמרצה Alberto Guadagnini
Politenico di Milanoמארגן המחלקה למדעי כדור הארץ וכוכבי הלכתצרו קשר -
Date:03ראשוןמרץ 2019הרצאה
EMERGING CONCEPTS IN BREAST CANCER
More information שעה 11:00 - 14:00כותרת Minerva and Dwek Institute for Cancer Therapy Research workshopמיקום בניין ע"ש מקס ולילאן קנדיוטימרצה Prof. Stefan Wiemann, Prof. Carlos Caldas, Prof. Sima Lev מארגן המחלקה לאימונולוגיה ורגנרציה ביולוגיתצרו קשר -
Date:04שנימרץ 2019הרצאה
IMM Guest seminar- Prof. Benny Chain will lecture about "The T cell receptor repertoire in health and disease."
More information שעה 13:00 - 14:00מיקום בניין וולפסון למחקר ביולוגימרצה Prof. Benny Chain
Division of Infection and Immunity, and Dept. of Computer Science , UCL, Londonמארגן המחלקה לאימונולוגיה מערכתיתצרו קשר -
Date:05שלישימרץ 2019הרצאה
Stem Cells, Regeneration and Aging Breakfast Seminar with Jacob Hanna
More information שעה 09:00 - 10:00מיקום בניין ע"ש מקס ולילאן קנדיוטימרצה Prof. Jacob Hanna
Department of Molecular Geneticsמארגן המחלקה לאימונולוגיה ורגנרציה ביולוגיתצרו קשר -
Date:05שלישימרץ 2019הרצאה
Adventures of bambusuril chemistry
More information שעה 11:00 - 12:00מיקום בניין הלן ומילטון קימלמןמרצה Prof. Vladimir Sindelar
Department of Chemistry & RECETOX Masaryk Universityמארגן המחלקה לכימיה מולקולרית ולמדע חומריםצרו קשר -
Date:05שלישימרץ 2019הרצאה
Biosynthesis and Secretion of Plant Cytokinins by Aphids
More information שעה 11:30 - 11:30מיקום בניין לביוכימיה על שם נלה וליאון בנוזיומרצה Prof. Georg Jander
Boyce Thompson Institute (BTI) for Plant Research, Ithaca, NY, USAמארגן המחלקה למדעי הצמח והסביבהצרו קשר -
Date:05שלישימרץ 2019הרצאה
Biosynthesis and Secretion of Plant Cytokinins by Aphids
More information שעה 11:30 - 11:30מיקום בניין לביוכימיה על שם נלה וליאון בנוזיומרצה Prof. Georg Jander
Boyce Thompson Institute (BTI) for Plant Research, Ithaca, NY, USAמארגן המחלקה למדעי הצמח והסביבהדף בית צרו קשר
