Human artificial chromosomes (HACs), including the de novo synthesized alphoidtetO-HAC, are a powerful tool for introducing genes of interest into eukaryotic cells. HACs are mitotically stable, ...non-integrative episomal units that have a large transgene insertion capacity and allow efficient and stable transgene expression. Previously, we have shown that the alphoidtetO-HAC vector does not interfere with the pluripotent state and provides stable transgene expression in human induced pluripotent cells (iPSCs) and mouse embryonic stem cells (ESCs). In this study, we have elaborated on a mouse model of ex vivo iPSC- and HAC-based treatment of hemophilia A monogenic disease. iPSCs were developed from FVIIIY/− mutant mice fibroblasts and FVIII cDNA, driven by a ubiquitous promoter, was introduced into the alphoidtetO-HAC in hamster CHO cells. Subsequently, the therapeutic alphoidtetO-HAC-FVIII was transferred into the FVIIIY/– iPSCs via the retro-microcell-mediated chromosome transfer method. The therapeutic HAC was maintained as an episomal non-integrative vector in the mouse iPSCs, showing a constitutive FVIII expression. This study is the first step towards treatment development for hemophilia A monogenic disease with the use of a new generation of the synthetic chromosome vector—the alphoidtetO-HAC.
In this work, a grid method for determining the aerodynamic characteristics of canard missiles, taking into account the effects of the oblique blowing is developed. Based on a comparison with NASA ...experimental data, the accuracy of the calculation results obtained by this method was tested. A comparative analysis of the canard missile flow spectra in the modes with the absence and presence of the oblique blowing is carried out. It is shown that the main mechanism for the oblique blowing formation is the interaction of vortices arose during the flow around the rudders and vortices coming off the missile body.
Results of studying the Pd/C and Pd/O powder catalysts synthesized by the deposition of 0.5 and 1.0 wt % Pd on carbon materials (Sibunit 159k, thermal carbon black T-900, Vulcan XC
-
72R) and oxide ...supports (Ox: γ-Al
2
O
3
, Cr
2
O
3
, Ga
2
O
3
, TiO
2
, Ta
2
O
5
, and V
2
O
5
, diatomaceous earth FW-70) and their catalytic properties in the partial hydrogenation of sunflower oil were described. Using a Parr fixed-bed reactor, comparative tests of the catalysts in the kinetic mode conducted to determine their activity (SCA,
V
0
) and
trans
-isomerization selectivity parameters (
S
tr
). The effect of the average particle size of supported palladium (
d
CO
) on these parameters in a wide range of
d
CO
values was discussed.
Muon catalyzed
dd
fusion in D
2
and HD gases in the temperature range from 28 to 350 K was investigated in a series of experiments based on a time-projection ionization chamber operating with pure ...hydrogen. All main observables in this reaction chain were measured with high absolute precision including the resonant and non-resonant
dd
μ formation rates, the rate for hyperfine transitions in
d
μ atoms, the branching ratio of the two charge symmetric fusion channels
3
He +
n
and
t
+
p
and the muon sticking probability. The report presents the final analysis of the data together with a comprehensive comparison with calculations based on recent μCF theories. The energy of the loosely bound
dd
μ state with quantum numbers
J
= 1,
ν
= 1, which is central to the mechanism of resonant molecule formation, is extracted with precision ɛ
11
(fit) = −1.9651(7) eV. in impressive agreement with the latest theoretical results ɛ
11
(theory) = −1.9646 eV.
Search for Muon Catalyzed 3Hed Fusion Fotev, V. D.; Ganzha, V. A.; Ivshin, K. A. ...
Physics of particles and nuclei,
06/2024, Volume:
55, Issue:
3
Journal Article
Peer reviewed
—This report presents the results of an experiment aimed at observation of the muon catalyzed
3
He
d
fusion reaction
3
He +
(3.66 MeV) +
p
(14.64 MeV) + μ which might occur after a negative muon stop ...in the D
2
+
3
He gas mixture. The basic element of the experimental setup is a Time Projection Chamber (TPC) which can detect the incoming muons and the products of the fusion reaction. The TPC operated with the D
2
+
3
He (5%) gas mixture at 31 K temperature. About
3
Heμ
d
molecules were produced with only 2 registered candidates for the muon catalyzed
3
He
d
fusion with the expected background
events. This gives an upper limit for the probability of the fusion decay of the
3
Heμ
d
molecule
at 90% C.L. Also presented are the measured formation rate of the
3
Heμ
d
molecule
and the probability of the fast muon transfer from the excited to the ground state of the
atom
. The obtained results are compared with the previously published data.
Platinum catalysts with the active component content of 5–40 wt % on various carbon supports have been synthesized by the reductive hydrolysis of platinum chloro complexes. The degree of dispersion ...of the supported platinum decreases with an increasing weight percentage of the metal in the catalyst. The following mechanism of Pt/C catalyst formation is deduced from experimental data: H
2
PtCl
6
adsorption on the support surface generates platinum nuclei, which then grow owing to the deposition of platinum ions under the action of an alkali and a reductant.
In this paper, a systematic investigation was carried out of activities at 80 °C of Pt supported on Sibunit-1562 graphitized carbon in the electroreduction of oxygen in the polymer electrolyte fuel ...cell. Pt content in the Pt/Sibunit-1562 catalysts was 20, 40, and 60 wt.% and Pt load at the cathode was varied in the 200–6.25 μgPt cm−2 interval. The results were compared with the activity of commercial 20 wt.% Pt/Vulcan XC-72 catalyst. To optimize the transport properties of the cathode layer and maintain its thickness upon using Pt/Sibunit −1562 catalysts with varied Pt content and Pt loads a definite amount of Vulcan-XC-72 carbon support was added to the cathode catalytic inks. Higher activity of Pt/Sibunit-1562 catalysts was found as compared to that of commercial 20 wt.% Pt/Vulcan XC-72 with similar particle size of the active component.
► New carbon material Sibunit-1562 was suggested as the cathode support for PEMFC. ► The effect of the addition of Vulcan XC-72 black carbon to the cathode layer was studied. ► The ORR activities of the series of 20, 40, and 60 wt.% Pt/Sibunit-1562 catalysts with different Pt loads were obtained in PEMFC.
A series of 50 wt% Pt/C catalysts based on carbon blacks with different specific surface areas and morphologies was synthesized and investigated using “start-stop” protocol (triangular scan in the ...1.0–1.5 V vs. reversible hydrogen electrode (RHE) potential range with a scan rate of 500 mV s
−1
). The commercial 40 wt% Pt/Vulcan XC-72 and 50 wt% Pt/TEC were used for comparison. The oxygen reduction reaction (ORR) activities and electrochemically active surface area (ECSA) of Pt were obtained at 25 °C in 0.1 M HClO
4
electrolyte after every 4000 cycles. All synthesized Pt/C catalysts were characterized by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), low-temperature nitrogen sorption, CO pulse chemisorption methods, and cycling voltammetry including a rotating disc electrode (RDE) method for analysis of the ORR kinetics. Dependences of the ORR activities, ECSA, and values of Tafel slopes on the number of oxidative cycles were obtained and analyzed in detail. It was shown that the initial values of Tafel slopes of the Pt/C catalysts decrease with increase of the surface area of carbon blacks. The increase in the values of Tafel slopes in the high-current density region with cycling was associated with the degradation of carbon support. The reciprocal ratios of the ECSA to initial values were found to grow linearly on the number of cycles. The ORR surface activity was significantly decreased in the first 8000–10,000 oxidation cycles as the result of changes of the active component and carbon support degradation. The following slight increase in the ORR surface activities with cycling was related to the increase in the Pt particle sizes in the Pt/C catalysts. Modification of Ketjen black EC 600 DJ through pyrocarbon deposition (KB600-C sample) led to appreciable increase of the stability of the Pt/KB600-C sample.
This work was carried out as part of a project aiming at a greatly improved measurement of the muon capture rate from the singlet state of the μp atom. The experiment will be performed at the intense ...muon beam of PSI using a new experimental method allowing high precision measurements of the lifetime of muons stopped in ultra-pure deuterium-depleted hydrogen (protium). The basic element of the detector is a time projection chamber operating in hydrogen gas at
10
bar
pressure. The arrival times and trajectories of the incoming muons and the outgoing decay electrons are measured with this device providing effective suppression of background. The system of chambers and electronics is designed for the large muon stop rates required for attaining high statistical accuracy. During four beam periods at PSI, data were taken. Also, various studies of the MWPC performance in hydrogen were made including ageing studies of the chambers under irradiation with stopped muons and with alpha and beta sources. It was demonstrated that the MWPCs can operate in pure hydrogen under 10 bar pressure with gas gains up to 5000, which is sufficient for the detection of relativistic electrons.
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