Disulfiram (DSF), a drug used in the treatment of alcoholism since 1948, has been shown to have antitumor properties in various tumor types possibly due to the induction of a type cell death, ...ferroptosis, and the sensitization of cells to chemo- and radiotherapy. In this study, we explored the antitumor properties of DSF in glioblastoma (GBM) and investigated the underlying molecular mechanisms.
GBM cell lines U251 and LN229 were treated with DSF to assess cytotoxicity and activity of the molecule in vitro. Response of cells to treatment was examined using cell viability, flow cytometry, LDH release assay, immunofluorescence and Western blot analysis.
DSF inhibited cell growth of GBM U251 and LN229 cell lines in vitro in a concentration-dependent manner. Flow cytometry demonstrated that DSF caused G0-G1 growth arrest. DSF treatment led to increased ROS and lipid peroxidation levels relative to controls indicating the involvement of ferroptosis. Furthermore, DSF triggered lysosomal membrane permeabilization (LMP), a critical mechanism promoting cell death, in a ROS-dependent manner. Finally, DSF enhanced radiosensitivity of U251 and LN229 cells.
Our findings indicated that DSF induced ferroptosis and LMP and enhanced the radiosensitivity of GBM cells. Therefore, DSF might have efficient antitumor activity in the treatment of human GBM.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
LaFe11.6Si1.4/16 wt%La70Co30 composites were fabricated by hot-pressing (HP) followed by thermal diffusion treatment in the temperature range of 923–1273 K. Significant microstructural and phase ...evolution occurred during diffusion heat treatment. Thermal decomposition (TD) occurred between 1023 and 1223 K, which increased the Curie temperature (TC) but smeared out the magnetic transition, decreasing magnetic entropy change (–ΔSM). Co atoms first diffused into the α-Fe(Si) and LaFeSi (1:1:1) phases. And then, the α-Fe(Co,Si) and La(Fe,Co)Si phases, attached to large LaFe11.6Si1.4 particles, transformed to a NaZn13-type La(Fe,Co,Si)13 (1:13) phase at 1273 K. Hence, a core-shell La(Fe,Co,Si)13 phase formed, resulting in a table-like magnetic entropy change over a wide temperature range (∼202–292 K). Greater Co diffusion and more homogeneity of the composition of the 1:13 phase could be achieved by increasing the annealing time. The maximum magnetic entropy change (–ΔSM)max of the composites at 0–2 T could be increased from 5.62 J/(kg·K) at ∼196 K to 8.81 J/(kg·K) at ∼244 K.
•La–Fe–Si/La–Co magnetocalric composites were fabricated by HP and high temperature annealing.•The process and mechanism of Co diffusion during GBD process was investigated.•The diffusion of Co was realized by firstly forming La(Fe,Co)Si (1:1:1) and α-Fe(Co,Si) phases.•1:1:1 and α-Fe(Co,Si) phases transformed to the 1:13 phase during diffusion annealing.•The (–ΔSM)max of the composites increases from 5.62J/kg·K at 196K to 8.81J/kg·K at 244K (2T).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We studied simultaneously the (4)He(e,e'p), (4)He(e,e'pp), and (4)He(e,e'pn) reactions at Q(2)=2(GeV/c)(2) and x(B)>1, for an (e,e'p) missing-momentum range of 400 to 830 MeV/c. The knocked-out ...proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A=2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum, in a region where the nucleon-nucleon (NN) force is expected to change from predominantly tensor to repulsive. The abundance of neutron-proton pairs is reduced as the nucleon momentum increases beyond ∼500 MeV/c. The extracted fraction of proton-proton pairs is small and almost independent of the missing momentum. Our data are compared with calculations of two-nucleon momentum distributions in (4)He and discussed in the context of probing the elusive repulsive component of the NN force.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Nicotine is known to influence locomotor activity. The alkaloid also intensifies gastric ulcer formation in stressed rats. The effects of nicotine on locomotor activity in relation to gastric lesions ...induced by restraint at 4 degrees C for 2 h (stress) were, therefore, studied. Ten-day treatment with nicotine 25 or 50 micrograms/ml drinking water potentiated stress-evoked ulceration and mast cell degranulation. These same doses of nicotine increased vertical motor activity; only the higher dose of the alkaloid enhanced horizontal movements. Phenobarbitone (12.5, 25, or 50 mg/kg, SC) dose dependently reduced vertical activity, as well as stress-induced gastric ulceration and mucosal mast cell degranulation. The drug also lessened the potentiating effects of nicotine on motor activity and stress-evoked gastric lesion formation. It is concluded that the ability of chronic nicotine treatment to intensify stress-induced gastric ulceration most likely owes part of its action to a mechanism evoking increased activity, which possibly reflects an influence on the CNS, as well as to enhancement of mast cell degranulation in the stomach glandular mucosa.
With the motivation to study how non-magnetic ion site disorder affects the quantum magnetism of Ba
CoSb
O
, a spin-1/2 equilateral triangular lattice antiferromagnet, we performed DC and AC ...susceptibility, specific heat, elastic and inelastic neutron scattering measurements on single crystalline samples of Ba
Sr
CoSb
O
with Sr doping on non-magnetic Ba
ion sites. The results show that Ba
Sr
CoSb
O
exhibits (i) a two-step magnetic transition at 2.7 K and 3.3 K, respectively; (ii) a possible canted 120 degree spin structure at zero field with reduced ordered moment as 1.24
/Co; (iii) a series of spin state transitions for both
∥
-plane and
∥
-axis. For
∥
-plane, the magnetization plateau feature related to the up-up-down phase is significantly suppressed; (iv) an inelastic neutron scattering spectrum with only one gapped mode at zero field, which splits to one gapless and one gapped mode at 9 T. All these features are distinctly different from those observed for the parent compound Ba
CoSb
O
, which demonstrates that the non-magnetic ion site disorder (the Sr doping) plays a complex role on the magnetic properties beyond the conventionally expected randomization of the exchange interactions. We propose the additional effects including the enhancement of quantum spin fluctuations and introduction of a possible spatial anisotropy through the local structural distortions.
Abstract
The selection of low-radioactive construction materials is of utmost importance for the success of low-energy rare event search experiments. Besides radioactive contaminants in the bulk, the ...emanation of radioactive radon atoms from material surfaces attains increasing relevance in the effort to further reduce the background of such experiments. In this work, we present the
$$^{222}$$
222
Rn emanation measurements performed for the XENON1T dark matter experiment. Together with the bulk impurity screening campaign, the results enabled us to select the radio-purest construction materials, targeting a
$$^{222}$$
222
Rn activity concentration of
$$10\,\mathrm{\,}\upmu \mathrm{Bq}/\mathrm{kg}$$
10
μ
Bq
/
kg
in
$$3.2\,\mathrm{t}$$
3.2
t
of xenon. The knowledge of the distribution of the
$$^{222}$$
222
Rn sources allowed us to selectively eliminate problematic components in the course of the experiment. The predictions from the emanation measurements were compared to data of the
$$^{222}$$
222
Rn activity concentration in XENON1T. The final
$$^{222}$$
222
Rn activity concentration of
$$(4.5\pm 0.1)\,\mathrm{\,}\upmu \mathrm{Bq}/\mathrm{kg}$$
(
4.5
±
0.1
)
μ
Bq
/
kg
in the target of XENON1T is the lowest ever achieved in a xenon dark matter experiment.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A series of chiral diphosphine ligands denoted as PQ-Phos was prepared by atropdiastereoselective Ullmann coupling and ring-closure reactions. The Ullmann coupling reaction of the biaryl diphosphine ...dioxides is featured by highly efficient central-to-axial chirality transfer with diastereomeric excess >99%. This substrate-directed diastereomeric biaryl coupling reaction is unprecedented for the preparation of chiral diphosphine dioxides, and our method precludes the tedious resolution procedures usually required for preparing enantiomerically pure diphosphine ligands. The effect of chiral recognition was also revealed in a relevant asymmetric ring-closure reaction. The chiral tether bridging the two aryl units creates a conformationally rigid scaffold essential for enantiofacial differentiation; fine-tuning of the ligand scaffold (e.g., dihedral angles) can be achieved by varying the chain length of the chiral tether. The enantiomerically pure Ru- and Ir-PQ-Phos complexes have been prepared and applied to the catalytic enantioselective hydrogenations of α- and β-ketoesters (CO bond reduction), 2-(6‘-methoxy-2‘-naphthyl)propenoic acid, alkyl-substituted β-dehydroamino acids (CC bond reduction), and N-heteroaromatic compounds (CN bond reduction). An excellent level of enantioselection (up to 99.9% ee) has been attained for the catalytic reactions. In addition, the significant ligand dihedral angle effects on the Ir-catalyzed asymmetric hydrogenation of N-heteroaromatic compounds were also revealed.
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IJS, KILJ, NUK, PNG, UL, UM
Conventional crystalline magnets are characterized by symmetry breaking and normal modes of excitation called magnons, with quantized angular momentum ħ. Neutron scattering correspondingly features ...extra magnetic Bragg diffraction at low temperatures and dispersive inelastic scattering associated with single magnon creation and annihilation. Exceptions are anticipated in so-called quantum spin liquids, as exemplified by the one-dimensional spin-1/2 chain, which has no magnetic order and where magnons accordingly fractionalize into spinons with angular momentum ħ/2. This is spectacularly revealed by a continuum of inelastic neutron scattering associated with two-spinon processes. Here, we report evidence for these key features of a quantum spin liquid in the three-dimensional antiferromagnet NaCaNi2F7. We show that despite the complication of random Na1+–Ca2+ charge disorder, NaCaNi2F7 is an almost ideal realization of the spin-1 antiferromagnetic Heisenberg model on a pyrochlore lattice. Magnetic Bragg diffraction is absent and 90% of the neutron spectral weight forms a continuum of magnetic scattering with low-energy pinch points, indicating NaCaNi2F7 is in a Coulomb-like phase. Our results demonstrate that disorder can act to freeze only the lowest-energy magnetic degrees of freedom; at higher energies, a magnetic excitation continuum characteristic of fractionalized excitations persists.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
Multiwavelength simultaneous observations are essential to the constraints on the origin of fast radio bursts (FRBs). However, it is a significant observational challenge due to the nature ...of FRBs as transients with a radio millisecond duration, which occur randomly in the sky regardless of time and position. Here, we report the search for short-time fast optical bursts in the Ground-based Wide Angle Camera (GWAC) archived data associated with FRB 20181130B, which were detected by the Five-hundred-meter Aperture Spherical radio Telescope and recently reported. No new credible sources were detected in all single GWAC images with an exposure time of 10 s, including images with coverage of the expected arrival time in optical wavelength by taking the high dispersion measurements into account. Our results provide a limiting magnitude of 15.43 ± 0.04 mag in the
R
band, corresponding to a flux density of 1.66 Jy or 8.35 mag in AB system by assuming that the duration of the optical band is similar to that of the radio band of about 10 ms. This limiting magnitude makes the spectral index of
α
< 0.367 from optical to radio wavelength. The possible existence of longer-duration optical emission was also investigated with upper limits of 0.33 Jy (10.10 mag), 1.74 mJy (15.80 mag), and 0.16 mJy (18.39 mag) for the durations of 50 ms, 10 s, and 6060 s, respectively. This undetected scenario could be partially attributed to the shallow detection capability, as well as the high inferred distance of FRB 20181130B and the low fluence in radio wavelength. The future detectability of optical flashes associated with nearby and bright FRBs are also discussed in this paper.
•Anodic aluminum oxide template was selected to fabricate matching layer.•PZT transducer with anodic aluminum oxide–epoxy matching layer has good properties.•Ultrasonic images of wire phantom were ...obtained.
The goal of this work is to demonstrate the application of anodic aluminum oxide (AAO) template as matching layer of ultrasonic transducer. Quarter-wavelength acoustic matching layer is known as a vital component in medical ultrasonic transducers to compensate the acoustic impedance mismatch between piezoelectric element and human body. The AAO matching layer is made of anodic aluminum oxide template filled with epoxy resin, i.e. AAO–epoxy 1–3 composite. Using this composite as the first matching layer, a ∼12MHz ultrasonic transducer based on soft lead zirconate titanate piezoelectric ceramic is fabricated, and pulse-echo measurements show that the transducer exhibits very good performance with broad bandwidth of 68% (−6dB) and two-way insertion loss of −22.7dB. Wire phantom ultrasonic image is also used to evaluate the transducer’s performance, and the results confirm the process feasibility and merit of AAO–epoxy composite as a new matching material for ultrasonic transducer application. This matching scheme provides a solution to address the problems existing in the conventional 0–3 composite matching layer and suggests another useful application of AAO template.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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