Electron-Equivalent Valency through Molecularly Well-Defined Multivalent DNA

2021 ◽  
Vol 143 (4) ◽  
pp. 1752-1757
Author(s):  
Ho Fung Cheng ◽  
Shunzhi Wang ◽  
Chad A. Mirkin
Keyword(s):  
Electron Equivalent

scholarly journals Gaseous Detector with Sub-keV Threshold to Study Neutrino Scattering at Low Recoil Energies

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
A. V. Kopylov ◽  
I. V. Orekhov ◽  
V. V. Petukhov ◽  
A. E. Solomatin
Keyword(s):  
Magnetic Moment ◽  
Precision Measurement ◽  
Rare Events ◽  
Coherent Scattering ◽  
Low Noise ◽  
Neutrino Scattering ◽  
Neutrino Magnetic Moment ◽  
Bench Scale ◽  
Electron Equivalent

Gaseous detector with a sub-keV electron equivalent threshold is a very perspective tool for the precision measurement of the neutrino magnetic moment and for observing coherent scattering of neutrinos on nuclei. The progress in the development of low noise electronics makes it possible to register the rare events at the threshold less than 100 eV. The construction of the gaseous detector is given and the typical pulses with amplitudes of a few eV observed on a bench scale installation are presented. The possible implications for future experiments are discussed.

scholarly journals Biohydrogen production from alkaline wastewater: The stoichiometric reactions, modeling, and electron equivalent

MethodsX ◽  
2019 ◽  
Vol 6 ◽  
pp. 1496-1505 ◽  
Author(s):  
Bijan Bina ◽  
Mohammad Mehdi Amin ◽  
Hamidreza Pourzamani ◽  
Ali Fatehizadeh ◽  
Mohammad Ghasemian ◽  
...  
Keyword(s):  
Biohydrogen Production ◽  
Electron Equivalent

Oxidation of tetrahydropterins by azide radical and the spectra of trihydropterin radicals

1990 ◽  
Vol 68 (11) ◽  
pp. 1974-1978 ◽  
Author(s):  
David A. Armstrong ◽  
Mohsen Farahani ◽  
Parminder S. Surdhar
Keyword(s):  
Rate Constants ◽  
Spectrophotometric Titration ◽  
Second Order ◽  
Strong Peak ◽  
Order Rate ◽  
Equivalent Point ◽  
Electron Equivalent

Spectrophotometric titration of tetrahydropterins with incremental amounts of •N3 showed that 6,7-dimethyl-7,8-dihydropterin was an intermediate in the oxidation of 6,7-dimethyltetrahydropterin at the two electron-equivalent oxidation point. The eventual end product at four electron equivalents was 6,7-dimethylpterin. In the case of unsubstituted tetrahydropterin, the dihydro form was clearly not an exclusive product at the two electron equivalent point, and this was attributed to the disproportionation of different forms of dihydropterin to tetrahydropterin and pterin.The azide radical oxidized tetrahydropterins to trihydropterin radicals, •PnH3, with overall second-order rate constants at pH 7 of 4.1, 3.8, and 2.9 × 109 M−1 s−1 for tetrahydropterin, 6,7-dimethyltetrahydropterin, and 6-carboxylated tetrahydropterin, respectively. At pH 10 the rate constants are slightly larger due to the presence of the deprotonated enolate forms of tetrahydropterins. Spectra vary somewhat with substitution in the pterin molecule, but all species have a strong peak (ε ~9000 M−1 cm−1) near 320 nm and lower absorption above this, with a tail extending to 580 nm. Keywords: tetrahydropterin oxidation, tetrahydropterin, trihydropterin radical, azide radical, trihydropterin spectrum.

scholarly journals Detection of cytochrome b+50 in membranes of Rhodospirillum rubrum isolated from aerobically and phototrophically grown cells

1980 ◽  
Vol 186 (2) ◽  
pp. 453-459 ◽  
Author(s):  
R A Niederman ◽  
C N Hunter ◽  
D E Mallon ◽  
O T Jones
Keyword(s):  
Cytochrome B ◽  
Rhodospirillum Rubrum ◽  
Electron Flow ◽  
Computer Assisted ◽  
Difference Spectra ◽  
Reduction Potentials ◽  
Oxidation Reduction ◽  
Assisted Analysis ◽  
Electron Equivalent ◽  
Three Components

1. Dark equilibrium potentiometric titrations were conducted on membranes purified from Rhodospirillum rubrum in an effort to identify b-type cytochrome components reported in other Rhodospirillaceae. In preparations from aerobically grown cells virtually devoid of bacteriochlorophyll a, three components were observed at 560-540 nm. Their oxidation-reduction midpoint potentials assigned by computer-assisted analysis were +195, +50 and −110 mV at pH 7.0; each of these fitted closely to theoretical single-electron equivalent curves. 2. In chromatophores from phototrophically grown carotenoidless mutant G-9, three components were also observed with E0' +190, +50 and −90mV. 3. The alpha-band of the +50mV component exhibited an absorption maximum near 560nm in difference spectra obtained at fixed oxidation-reduction potentials. 4. This component could be demonstrated most readily in purified membrane preparations and may have been obscured in previous studies by residual cytochrome c'. 5. This is the first definitive report of cytochrome b+50 in membranes from Rs. rubrum and aligns this bacterium with other Rhodospirillaceae in which this component functions in light-driven cyclic electron flow.

scholarly journals Analysis of the 40K contamination in NaI(Tl) crystals from different providers in the frame of the ANAIS project

2014 ◽  
Vol 29 (19) ◽  
pp. 1443010 ◽  
Author(s):  
C. Cuesta ◽  
J. Amaré ◽  
S. Cebrián ◽  
E. García ◽  
C. Ginestra ◽  
...  
Keyword(s):  
Dark Matter ◽  
Sodium Iodide ◽  
Low Energy ◽  
Annual Modulation ◽  
Dark Matter Search ◽  
Scintillation Signal ◽  
Nuclear Recoils ◽  
Search Experiment ◽  
Low Efficiency ◽  
Electron Equivalent

NaI(Tl) large crystals are applied in the search for galactic dark matter particles through their elastic scattering off the target nuclei in the detector by measuring the scintillation signal produced. However, energies deposited in the form of nuclear recoils are small, which added to the low efficiency to convert that energy into scintillation, makes that events at or very near the energy threshold, attributed either to radioactive backgrounds or to spurious noise (nonbulk NaI(Tl) scintillation events), can compromise the sensitivity goals of such an experiment. DAMA/LIBRA experiment, using 250 kg NaI(Tl) target, reported first evidence of the presence of an annual modulation in the detection rate compatible with that expected for a dark matter signal just in the region below 6 keVee (electron equivalent energy). In the frame of the ANAIS (Annual modulation with NaI Scintillators) dark matter search project a large and long effort has been carried out in order to understand the origin of events at very low energy in large sodium iodide detectors and develop convenient filters to reject those nonattributable to scintillation in the bulk NaI(Tl) crystal. 40K is probably the most relevant radioactive contaminant in the bulk for NaI(Tl) detectors because of its important contribution to the background at very low energy. ANAIS goal is to achieve levels at or below 20 ppb natural potassium. In this paper we will report on our effort to determine the 40K contamination in several NaI(Tl) crystals, by measuring in coincidence between two (or more) of them. Results obtained for the 40K content of crystals from different providers will be compared and prospects of the ANAIS dark matter search experiment will be briefly reviewed.

ChemInform Abstract: Trisubstituted Stannyllithium as a Double Electron Equivalent. Reaction with α,β-Enones.

ChemInform ◽  
1988 ◽  
Vol 19 (37) ◽  
Author(s):  
T. SATO ◽  
M. WATANABE ◽  
T. WATANABE ◽  
Y. ONODA ◽  
E. MURAYAMA
Keyword(s):  
Double Electron ◽  
Electron Equivalent
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