• In this study electron paramagnetic resonance spectroscopy with spin trapping has been used to identify radicals formed on collagen and related materials by metal ion-H2O2 mixtures. (ku.dk)
  • Here, we used pulse EPR (electron paramagnetic resonance) spectroscopy to determine the stabilities of nanoscopic assemblies formed between one or two nitroxide spin-labelled tridentate 2,2′:6′,2′′-terpyridine (tpy) ligands and divalent metal ions (FeII, ZnII, CoII and CuII). (st-andrews.ac.uk)
  • 3. I. Yamazaki, H. S. Mason and L. H. Piette: Identification of Intermediate Substrate Free-Radicals Formed During Peroxidatic Oxidations by Electron Paramagnetic Resonance Spectroscopy. (rockychem.com)
  • Results obtained from x-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) analyses suggest that the doped N species reside at interstitial lattice positions in the catalyst. (cambridge.org)
  • The powders are characterized by differential thermal and thermogravimetric analyses (DTA-TG), mass spectroscopy, dilatometry, X-ray diffraction (XRD), magic angle spinning nuclear magnetic resonance (MAS NMR), Raman spectroscopy, X-ray photoelectron spectra (XPS) and electron spin resonance (ESR). (fbk.eu)
  • Infrastructures for transmission- and scanning electron microscopy, photoelectron spectroscopy, nuclear magnetic resonance and magnetic resonance imaging, mass spectroscopy, crystallography, additive manufacturing, as well as dedicated fabrication and synthesis laboratories for electronic and circular materials are being financed. (lu.se)
  • Nuclear Magnetic Resonance Spectroscopy: Introduction. (iitk.ac.in)
  • Carbon-13 Nuclear Magnetic Resonance Spectroscopy, G. C. Levy, R. L. Lichter and G. L. Nelson, Wiley, 1980. (iitk.ac.in)
  • 4. Z. Luz and B.L. Silver, The acid catalyzed exchange of phosphorus bonded hydrogen in aqueous solutions of dialkyl phosphonates studied by nuclear magnetic resonances. (weizmann.ac.il)
  • 7. M. Sheinblatt and Z. Luz, Hydrogen exchange in benzylmercaptan studied by nuclear magnetic resonance. (weizmann.ac.il)
  • 9. Z. Luz and S. Meiboom, Nuclear magnetic resonance study of the protolysis of trimethylammonium ion in aqueous solution-order of the reaction with respect to water. (weizmann.ac.il)
  • 11. Z. Luz and S. Meiboom, Nuclear magnetic resonance study of the solvation of Co++ in methanol-water mixtures. (weizmann.ac.il)
  • 14. Z. Luz, Nuclear magnetic resonance and optical spectroscopy of [Co(MeOH)5Cl]+ in methanol and the kinetics of methanol exchange of the solvation shell. (weizmann.ac.il)
  • 15. Z. Luz, Nuclear magnetic resonance study of cobalt-chlorine complexes in methanol. (weizmann.ac.il)
  • 19. I. Pecht and Z. Luz, Oxygen exchange between periodate and water studied by 17O nuclear magnetic resonance. (weizmann.ac.il)
  • 21. Z. Luz and G. Yagil, Water 17O nuclear magnetic resonance shift in aqueous solutions of 1:1 electrolyte. (weizmann.ac.il)
  • 22. Z. Luz and B.L. Silver, The acid catalyzed oxygen exchange of acetyl-acetone in dioxane-water solution measured by oxygen-17 nuclear magnetic resonance. (weizmann.ac.il)
  • 23. B.L. Silver, Z. Luz, S. Peller and J. Reuben, Intramolecular hydrogen bonding in the hydrogen anions of some carboxylic acids in water-methanol mixtures, Evidence from nuclear magnetic resonance. (weizmann.ac.il)
  • 24. Z. Luz and I. Pecht, Oxygen-17 nuclear magnetic resonance and oxygen exchange in aqueous solutions of telluric acid. (weizmann.ac.il)
  • 28. Z. Luz, B.L. Silver and D. Fiat, O-17 nuclear magnetic resonance of manganese (III) tris(acetyacetonate). (weizmann.ac.il)
  • 29. P. Greenzaid, Z. Luz and D. Samuel, A nuclear magnetic resonance study of the reversible hydration of aliphatic aldehydes and ketones. (weizmann.ac.il)
  • Our resources in infrared spectroscopy, mass spectrometry, nuclear magnetic resonance spectroscopy, electron spin resonance, laser spectroscopy, computer facilities for theoretical organic, and X-ray crystallography are state-of-the-art. (umn.edu)
  • 2. L. H. Piette and W. A. Anderson: Potential Energy Barrier Determinations for Some Alkyl Nitrites by Nuclear Magnetic Resonance. (rockychem.com)
  • This result is counterintuitive, as 2-4 are relatively richer in 1H nuclear spin, hence, expected to have shorter T m. (du.edu)
  • Thus, these data suggest an important role for counterion methyl groups on T m, and moreover provide the first instance of a lengthening T m with increasing nuclear spin quantity on a molecule. (du.edu)
  • In particular, they are and nuclear magnetic resonance (NMR) refinement. (lu.se)
  • Particle uptake and the cellular dose of Cu were investigated by transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. (biomedcentral.com)
  • The presence of a 0.3 to 1.9 nm thick surface layer of disordered nanomaterial separating the cubic ZnS cores and its shrinking to a few atomic layers by mass loss after annealing up to 350 °C was observed by high resolution transmission electron microscopy. (acs.org)
  • Lawrence Livermore National Laboratory, Livermore, CA, USA - Bryan W. Reed and co-researchers used a PulseBlasterESR-PRO-500 in their work on Irreversible reactions studied with nanosecond transmission electron microscopy movies: Laser crystallization of phase change materials, which won an R&D100 award. (spincore.com)
  • Fluorescence spectroscopy: Fluorescence energy transfer and its applications to measurement of distances in molecules. (iitk.ac.in)
  • In vivo experiments demonstrate that these nanocapsules can target to tumor sites through fluorescence/magnetic resonance imaging and offer remarkable therapeutic results. (nature.com)
  • Conformational studies were performed making use of the spectroscopic techniques circular dichroism (CD), electron paramagnetic resonance (EPR), and fluorescence. (bvsalud.org)
  • We then train an artificial neural network to process the fluorescence photon data in the rest frame of the rotating crystal in order to identify ion locations with a precision of $~90%$, accounting for substantial illumination inhomogeneity across the crystal. (edu.au)
  • Therefore, the author decided to investigate the radicals in the gas phase by laser-induced fluorescence (LIF) and to observe the surface 'in situ' by infrared spectroscopy. (nagoya-u.ac.jp)
  • Using transition metal ions for spin-based applications, such as electron paramagnetic resonance imaging (EPRI) or quantum computation, requires a clear understanding of how local chemistry influences spin properties. (du.edu)
  • This altered behaviour is believed to be due to the binding of copper ions to some substrates and hence site-specific damage. (ku.dk)
  • Experimental studies have reported elevated levels of iron and copper (Cu) in diseased human arteries but have often used methods that release metal ions from proteins. (ku.dk)
  • METHODS AND RESULTS: In this study, we have used the minimally invasive technique of electron paramagnetic resonance (EPR) spectroscopy and inductively coupled plasma mass spectroscopy (ICPMS) to quantify iron and copper in ex vivo healthy human arteries and carotid lesions. (ku.dk)
  • The chelation of copper ions using tetrathiomolybdate (TTM) prevented cell death whereas inhibition of the cellular SOD1 chaperone aggravated toxicity. (biomedcentral.com)
  • The study focuses on open questions related to the oxidation state of the copper ions, identification of their local sites and on the influence of the surrounding on the radiative and spin relaxation times. (technion.ac.il)
  • The active components were detected by electron spin-resonance spectroscopy (ESR) and the quenching experiments. (bvsalud.org)
  • Part of SPIRAL2 is the S3 (Super Separator Spectrometer), a device designed for experiments with very high intensity stable ion beams. (cryomagnetics.com)
  • In three distinct approaches we exploited (a) the modulation depth of pulsed electron-electron double resonance (PELDOR) experiments in samples with increasing metal-to-ligand ratios, (b) the frequencies of PELDOR under broadband excitation using shaped pulses and (c) the distances recovered from well-resolved PELDOR data in fully deuterated solvents measured at 34 GHz. (st-andrews.ac.uk)
  • Here, we combine in-vitro structural measurements, which used EPR spectroscopy and UV-Vis measurements, with cell experiments to explore the role of the various methionine residues in CusB. (biorxiv.org)
  • Shortly after the invention of spin labeling, Dr. Piette originated several much imitated experiments. (rockychem.com)
  • Neon: properties of free atoms Neon atoms have 10 electrons and the shell structure is 2.8. (web.app)
  • The ground state electron configuration of ground state gaseous Electronic configuration, the arrangement of electrons in energy levels around an has one 3s electron in excess of the noble gas neon (chemical symbol Ne, Both atoms have a filled s subshell outside their filled inner shells. (web.app)
  • Write the electron configuration and draw the orbital notation for atoms of oxygen and sulfur. (web.app)
  • Quantum information has preferentially considered simpler systems than electrons in atoms or molecules like photons, ions in a trap, cold atoms, superconducting circuits, etc. (lu.se)
  • We photoionize atoms using short extreme ultraviolet pulses and probe the emitted electron with a delayed, spectrally tunable, bichromatic infrared pulse. (lu.se)
  • In general, the computational load rises rapidly with the number of atoms and electrons considered and therefore, only rather small systems can be studied accurately. (lu.se)
  • Iron exists in numerous forms in water and is commonly bonded or co-ordinated to other species such as water molecules or electron donor partners (Johnson et al 2007). (europa.eu)
  • Electron Paramagnetic Resonance (EPR) is a branch of spectroscopy that observes the spin of unpaired electrons in free radicals, excited states of molecules, metal ions and magnetic materials. (ua.edu)
  • 3. B.L. Silver and Z. Luz, Rates and mechanisms of protolysis of trimethyl-phosphonium ion in aqueous solution studied by proton magnetic resonance. (weizmann.ac.il)
  • This course emphasizes quantitative and graphical interpretation of acid-base, solubility, distribution, complex ion, and redox equilibria in aqueous solution and soils. (beloit.edu)
  • CD spectroscopy: CD of polypeptides and nucleic acids, Induced CD, magnetic circular dichroism. (iitk.ac.in)
  • Protein aggregation was determined by confocal microscopy using an aggresome-specific dye and protein misfolding was determined by circular dichroism (CD) spectroscopy. (biomedcentral.com)
  • Post-explosion aerosols were collected on anodisc filters and analyzed by scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS). (cdc.gov)
  • Lund University is funded 45,5 MSEK for electron microscopy, and the technology platform is run together with KTH and Stockholm University for a total of nearly 103 MSK. (lu.se)
  • 20. Z. Luz and R.G. Shulman, Proton magnetic resonance shifts in aqueous solutions of paramagnetic metal ions. (weizmann.ac.il)
  • AG was supported by the EPSRC funded Centre for Doctoral Training in 'integrated magnetic resonance' (EP/J500045/1). (st-andrews.ac.uk)
  • In 1972, Dr. Piette was awarded a Guggenheim Fellowship and spent a year in Paris and Grenoble developing novel biochemical applications of magnetic resonance spectroscopy. (rockychem.com)
  • The carrier-impurity interaction was mainly investigated using an optically detected magnetic resonance (ODMR) spectroscopy. (technion.ac.il)
  • An ODMR spectrum refers to a plot of a change in luminescence intensity due to a magnetic resonance perturbation at the excited state. (technion.ac.il)
  • In other words, we aim at developing "attosecond quantum electronics", quantum electronics not referring here to the physics of few-level systems in a laser medium, but to the quantum behavior of ultrashort electron wavepackets created by the absorption of attosecond light pulses. (lu.se)
  • to create and follow in time entangled two-electron attosecond wavepackets. (lu.se)
  • Description of the spin Hamiltonian of the Mn 2+ centers in cZnS QDs and of the EPR spectra analysis procedure. (acs.org)
  • In order to analyze the surface reactions, the author has observed the surface during the etching process using various spectroscopic techniques such as infrared spectroscopy and electron spin resonance, and have tried to understand the surface reaction through physicochemical analysis. (nagoya-u.ac.jp)
  • Interaction of a high-intensity optical laser beam with a solid target can generate `hot' electrons, which generate radiation hazards (mainly bremsstrahlung photons and neutrons) from interaction of hot electrons with target and the surrounding materials. (lu.se)
  • Current research focuses on the cytochrome bc1 complex which sits in the mitochondrial membrane and uses electron transport to pump protons across the membrane and provide the driving force for ATP synthase. (ua.edu)
  • In order to write the Ne electron configuration we first need to know t Neon is a chemical element with atomic number 10 which means there are 10 protons and 10 electrons in the atomic structure. (web.app)
  • Since the atomic number is always equal to the number of protons or Z = number of protons and in ground state (no charge), the number of protons is equal to the number of electrons, then Z = number of protons = number of electrons (ground state) Therefore, the ground state electron configuration of Question: - Part A Enter The Electron Configuration For Ne. (web.app)
  • Not only do our chemical models allow studying metal-ligand interactions via PELDOR spectroscopy, the design of our study is directly transferable to (bio)macromolecular systems for determining the kinetic and thermodynamic stabilities underpinning (templated) multimerisation. (st-andrews.ac.uk)
  • 2) Surface interactions of CFx ions (Section 3. (nagoya-u.ac.jp)
  • Theoretical model, using spin Hamiltonian containing Zeeman interaction, carrier-impurity spin-exchange, and electron-hole exchange interactions, assisted in simulating the ODMR spectrum. (technion.ac.il)
  • The journal encourages contributions in the general area of atomic, molecular, ionic, liquid and solid state spectroscopy carried out using electron impact, synchrotron radiation (including free electron lasers) and short wavelength lasers. (materialstoday.com)
  • Papers using photoemission and other techniques, in which synchrotron radiation, Free Electron Lasers, laboratory lasers or other sources of ionizing radiation, combined with electron velocity analysis are especially welcome. (materialstoday.com)
  • To reduce electron losses and decrease radiation levels around the syn-chrotron, optimizations of the electron beam during injection into the storage ring, ramping and standard operation were carried out. (lu.se)
  • X-ray photoemission spectroscopy detected increased surface oxygen contents on particles in co-exposure aerosols. (cdc.gov)
  • Extensive characterization including infrared and X-ray spectroscopy, thermogravimetric analysis, size, charge, surface area, and density captured the alteration in physicochemical properties as the material went through sequential purification. (cdc.gov)
  • ATC chillers are well established in the scientific instrument support markets (electron microscopes, X-ray diffraction, ICPMS etc.), semiconductor process, ophthalmic lens manufacturing equipment, machine tool, and more recently the chillers of choice for commercial digital printing and laser lithography markets worldwide. (biochannelpartners.com)
  • Astatine - [Xe] 4f145d106s26p5 This app includes general properties, physical properties, atomic properties, electron shell diagrams and pictures of chemical elements. (web.app)
  • Aluminum ( atomic number 13), with 13 electrons and the electron configuration [Ne]3s23p1, is Electron configuration is a shorthand notation for us to designate the atomic orbitals to F. You can see that F- has the same configuration that Ne would have. (web.app)
  • Condensed electron configuration: has the element symbol of the previous noble gas in square brackets 1 Al (Z = 13) 1s22s22p63s23p1 ↑↓ 3s 3p ↑ Al has the condensed configuration [Ne]3s23p1 2015-11-11 · 1s^2 2s^2 2p^6 3s^2 3p^6 Based on the periodic table, the atomic number (Z of chlorine is 17. (web.app)
  • Indeed, building on the expertise, methods and infrastructure used in that research, our faculty's continued to explore novel phenomenology in condensed matter, and our efforts were rewarded in 2007 with a groundbreaking discovery when the Molenkamp group demonstrated the Quantum Spin Hall Effect in a HgTe heterostructure, the first experimental realization of a topological insulator. (uni-wuerzburg.de)
  • Electron spin resonance (ESR) spectroscopy is the method of choice for characterizing paramagnetic impurities in a sample, with applications ranging from chemistry to quantum computing but it gives access only to ensemble-averaged quantities due to its limited signal-to-noise ratio. (in2p3.fr)
  • Resolving the locations and discriminating the spin states of individual trapped ions with high fidelity is critical for a large class of applications in quantum computing, simulation, and sensing. (edu.au)
  • These include both the inherent quantum bit systems and materials playing supportive or enabling roles, and cover trapped ions, neutral atom arrays, rare earth ion systems, donors in silicon, color centers and defects in wide-band gap materials, two-dimensional materials and superconducting materials for single-photon detectors. (edu.au)
  • Thermally induced changes in the structure and composition of the shell of tightly aggregated cubic ZnS/Zn(OH) 2 core-shell quantum dots of 1.9 nm average core size were investigated by multifrequency electron paramagnetic resonance of Mn 2+ probing ions. (acs.org)
  • Unexplained correlations in photon emission times within a linear chain of trapped ions have been reported, which, if genuine, cast doubt on the potential of an ion trap to realize quantum information processing. (edpsciences.org)
  • Harvard University, USA - Dominik B. Bucher, Diana P. L. Aude Craik, Mikael P. Backlund, Matthew J. Turner, Oren Ben Dor, David R. Glenn & Ronald L. Walsworth used a PulseBlasterESR-PRO-500 in their work on Quantum diamond spectrometer for nanoscale NMR and ESR spectroscopy . (spincore.com)
  • After several years of successful operation in the Collider Accelerator Department Electron Beam Ion Source (EBIS), the customer decided to upgrade their capabilities by adding a second Cryomagnetics' magnet system. (cryomagnetics.com)
  • The SPIRAL2 project at France's GANIL (Grand Accélérateur National d'Ions Lourds) laboratory will significantly extend the research possibilities of Radioactive Ion Beam (RIB) physics. (cryomagnetics.com)
  • Since the vertical process ability of plasma etching is caused by the reaction of ions, the interaction between ions and surfaces has been investigated by irradiating the surface with a beam of controlled ions. (nagoya-u.ac.jp)
  • SESAME (Synchrotron-light for Experimental Science and Application in the Middle East) is Mid-dle East's first major international research centre, it is third generation light source located in Allan-Jordan using 2.5GeV, 400mA electron beam. (lu.se)
  • In 1975, Dr. Piette performed the first in vivo ESR experiment using spin labels and a helix implanted in the liver of a rat. (rockychem.com)
  • Compared with individual exposures, co-exposure aerosols produced greater acellular and cellular oxidants detected by electron paramagnetic resonance (EPR) spectroscopy, and in vivo immune-spin trapping (IST), as well as synergistically increased lavage neutrophils, lavage proteins and inflammation related gene/protein expression. (cdc.gov)
  • Such microbubble stabilization and conversion might be caused by the formation of solid microbubble shells generated by iron ions in the condensed ionic cloud around the microbubble. (elsevierpure.com)
  • Herein we report a series of four ionic complexes to provide the first systematic study of one aspect of local chemistry on the V(IV) spin - the counterion. (du.edu)
  • In this study Mssbauer, EPR, and UV-vis spectroscopies were used to characterize the Fe distribution in Aft1-1(up) and Yah1p-depleted cells. (tamu.edu)
  • Our first objective is to characterize electron wavepackets created by photoionization. (lu.se)
  • This technique can be used to analyze spatial and temporal correlations in arrays of hundreds of trapped-ion qubits. (edu.au)
  • The process of photoreduction may overcompensate the aerobic oxidation resulting in the presence of ferrous (Fe2+) ions during daylight and disappearing during the night (Kopácek et al 2005). (europa.eu)
  • Electron Configuration and Oxidation States of Neon Electron configuration of Neon is [He] 2s2 2p6. (web.app)
  • This level of control is required in a range of important applications including analytical instrumentation such as electron microscopes, mass spectrometers and X-ray diffraction, through to industrial process control. (biochannelpartners.com)
  • The results demonstrate that PELDOR is highly sensitive to resolving the stability of templated dimers and allows to readily distinguish anti-cooperative binding (for CuII ions) from cooperative binding (for CoII or FeII ions). (st-andrews.ac.uk)
  • Modulation dependence ODMR can revile the spin dynamics in the NCs. (technion.ac.il)
  • Matter exposed to these ultrashort XUV light pulses ionizes and temporally-confined coherent electron wave packets are created. (lu.se)
  • its ability to exchange electrons as it cycles between cuprous and cupric states has been harnessed by enzymes that catalyze a wide variety of biochemical processes [ 1 , 2 ]. (biorxiv.org)
  • In the following, we refer to pump of halophilic archaebacteria, has become the these as the extracellular (EC) channel and the paradigm of membrane proteins in general and ion cytoplasmic (CP) channel. (lu.se)
  • Room temperature, solution X-band ( ca. 9.8 GHz) continuous-wave electron paramagnetic resonance (CW-EPR) spectroscopy revealed an increasing linewidth with larger cations, likely a counterion-controlled tumbling in solution via ion pairing. (du.edu)
  • Here, we report a new method for the detection of single electron spins at millikelvin temperatures. (in2p3.fr)
  • The confined structures enhance interaction between photo-generated carriers (electron and hole) and spins of the magnetic impurities, hence, encouraging unique properties, like giant magnetization and giant g-factor of the carriers. (technion.ac.il)
  • So, selective positioning of magnetic impurities in the shell regime permits selective monitoring of the electron-Mn +2 spin-exchange interaction. (technion.ac.il)
  • OH-] = hydroxyl ion activity. (europa.eu)
  • Electron spin resonance spectroscopy (ESR) confirmed the generation of hydroxyl radicals under strongly acidic conditions. (elsevierpure.com)
  • Bulk nanobubbles were expected to be the source of the spin-adducts of hydroxyl radicals. (elsevierpure.com)
  • Some casinos have lucky days when they significantly increase the bonuses or offer free spins and games, casino765 free spins. (apostolicfaithwharton.org)
  • 9.4 Tesla (400MHz) 10ppm Cryogen-FREE Magnet System for Electron Spin Resonance. (cryomagnetics.com)
  • Prof. Bowman's research interests center on free radical reactions in proteins and other ordered but non-crystalline environments and on the application of pulsed EPR spectroscopy to determine the structure and function of enzymes, free radicals and materials. (ua.edu)
  • Nowadays, they can also be produced in plasmas produced by high-power lasers, and very recently using free electron lasers. (lu.se)
  • The metal ion employed has a dramatic effect on the species observed. (ku.dk)
  • In the GA/Fe3O4/PMS system, the trace amount of dissolved iron ion were not the main species that activated PMS. (bvsalud.org)
  • Powders of TiO 2 doped with a metal ion and N species were prepared by a polymerized complex method and the visible-light photocatalytic activities of the products are investigated. (cambridge.org)
  • If the molecular species is excessive in electrons, it will be negatively charged, and if it is insufficient, it will be positively charged. (als-japan.com)
  • This could be due to the involvement of other chemical species in the gas phase, such as ions, or the modification of the surface to facilitate the deposition of the a-C:F film. (nagoya-u.ac.jp)
  • The materials properties addressed include characterization of ground and excited state properties as well as time resolved electron dynamics. (materialstoday.com)
  • The behaviour of ions of iron (Fe2+ and Fe3+) in solution is dependent on the different conditions. (europa.eu)
  • Moreover, adhesions of the polymers were tested by making hydrogels using iodate (IO3-) and iron (III) (Fe3+) ions. (iyte.edu.tr)
  • The N-terminus-acetylated form of NGF(1-14) was also investigated to evaluate the involvement of the Ser1 alpha-amino group in metal-ion coordination. (cnr.it)
  • When this wavepacket is fully coherent, its phase can be determined by an interference technique (named RABBIT) involving two-photon transitions: two-photon absorption of a high-order harmonic and a laser photon, and absorption of the next harmonic close to the resonance and emission of a laser photon, leading to the creation of a sideband. (lu.se)
  • 6. Z. Luz and B.L. Silver, NMR study of the exchange of phosphorus bonded hydrogen in dimethyl- and diethylphosphonate, catalyzed by acetate ion. (weizmann.ac.il)
  • Because the unpaired electrons are often the most reactive sites, EPR provides a highly selective method to study the sites that are most interesting to chemists, biologists and physicists. (ua.edu)
  • The study revealed spin-flip processes of both electron and hole with g-phenomenological factors deviating from the electronic band-edge, indicating their localization or shallow trapping at halide or metal vacancies. (technion.ac.il)
  • We will study the properties of the electronic states created by interferences of the electron wavepackets and their temporal evolution. (lu.se)
  • The discussed materials are of particular interest for various future applications such as electro-luminescent display, photovoltaic cells, and spin-based technologies. (technion.ac.il)