721 research outputs found
1-(4-Chlorophenyl)-3-{5-[(E)-2-phenylethenyl]-1,3,4-thiadiazol-2-yl}urea
In the title compound, C17H13ClN4OS, the 1,3,4-thiadiazole ring makes dihedral angles of 9.70 (15) and 7.22 (10)° with the benzene and phenyl rings, respectively; the dihedral angle between these two rings is 6.37 (19)°. In the crystal, pairs of N—H⋯N and C—H⋯O hydrogen bonds between inversion-related molecules result in supramolecular ribbons displaying alternate R
2
2(8) and R
2
2(14) graph-set ring motifs
Possible singlet and triplet superconductivity on honeycomb lattice
We study the possible superconducting pairing symmetry mediated by spin and
charge fluctuations on the honeycomb lattice using the extended Hubbard model
and the random-phase-approximation method. From to doping levels,
a spin-singlet -wave is shown to be the leading
superconducting pairing symmetry when only the on-site Coulomb interaction
is considered, with the gap function being a mixture of the nearest-neighbor
and next-nearest-neighbor pairings. When the offset of the energy level between
the two sublattices exceeds a critical value, the most favorable pairing is a
spin-triplet -wave which is mainly composed of the next-nearest-neighbor
pairing. We show that the next-nearest-neighbor Coulomb interaction is also
in favor of the spin-triplet -wave pairing.Comment: 6 pages, 4 figure
A study on the preparation and characterization of plasmid DNA and drug-containing magnetic nanoliposomes for the treatment of tumors
Zi-Yu Wang1,2, Li Wang1, Jia Zhang1, Yun-Tao Li1, Dong-Sheng Zhang11School of Medicine, Southeast University, Nanjing, China; 2School of Basic Medical Sciences, Nanjing University of Traditional Chinese Medicine, Nanjing, ChinaPurpose: To explore the preparation and characterization of a novel nanosized magnetic liposome containing the PEI-As2O3/Mn0.5Zn0.5Fe2O4 complex.Methods: Mn0.5Zn0.5Fe2O4 and As2O3/Mn0.5Zn0.5Fe2O4 nanoparticles were prepared by chemical coprecipitation and loaded with PEI. The PEI-As2O3/Mn0.5Zn0.5Fe2O4 complex was characterized using transmission electron and scanning electron microscopy, X-ray diffraction, energy dispersive spectrometry, and Fourier transform infrared spectroscopy. Cell transfection experiments were performed to evaluate the transfect efficiency. Magnetic nanoliposomes were prepared by rotatory evaporation and their shape, diameter, and thermodynamic characteristics were observed.Results: Mn0.5Zn0.5Fe2O4 and PEI-As2O3/Mn0.5Zn0.5Fe2O4 nanoparticles were spherical, with an average diameter of 20–40 nm. PEI-As2O3/Mn0.5Zn0.5Fe2O4 was an appropriate carrier for the delivery of a foreign gene to HepG2 cells. Energy dispersive spectrometry results confirmed the presence of the elements nitrogen and arsenic. Nanoliposomes of approximately 100 nm were observed under a transmission electron microscope. Upon exposure to an alternating magnetic field, they also had good magnetic responsiveness, even though Mn0.5Zn0.5Fe2O4 was modified by PEI and encased in liposomes. Temperatures increased to 37°C–54°C depending on different concentrations of PEI-As2O3/Mn0.5Zn0.5Fe2O4 and remained stable thereafter.Conclusion: Our results suggest that PEI-As2O3/Mn0.5Zn0.5Fe2O4 magnetic nanoliposomes are an excellent biomaterial, which has multiple benefits in tumor thermotherapy, gene therapy, and chemotherapy.Keywords: nanoliposomes, magnetic fluid hyperthermia, As2O3, DN
Particular solutions of singularly perturbed partial differential equations with constant coefficients in rectangular domains, Part I. Convergence analysis
AbstractThe technique of separation of variables is used to derive explicit particular solutions for constant coefficient, singularly perturbed partial differential equations (PDEs) on a rectangular domain with Dirichlet boundary conditions. Particular solutions and exact solutions in closed form are obtained. An analysis of convergence for the series solutions is performed, which is useful in numerical solution of singularly perturbed differential equations for moderately small values of ε (e.g., ε=0.1–10−4). Two computational models are designed deliberately: Model I with waterfalls solutions and Model II with wedding-gauze solutions. Model II is valid for very small ε (e.g., ε=10−7), but Model I for a moderately small ε(=0.1–10−4). The investigation contains two parts. The first part, reported in the present paper, focuses on the convergence analysis and some preliminary numerical experiments for both of the models, while the second part, to be reported in a forthcoming paper, will illustrate the solutions near the boundary layers
(Z)-Isobutyl 2-benzamido-3-(4-chlorophenyl)acrylate
The title compound, C20H20ClNO3, is a α-amino acid derivative which displays a Z configuration about the C=C double bond. The dihedral angle betwen the aromatic rings is 87.75 (12)°. The molecular conformation is stabilized by an intramolecular C—H⋯N hydrogen bond. In the crystal structure, centrosymmetrically related molecules interact through intermolecular C—H⋯O hydrogen-bond interactions, forming dimers. The dimers are further linked into chains parallel to the a axis by N—H⋯O hydrogen bonds. The methyl groups of the isopropyl group are disordered over two positions with occupancy factors of 0.5
A broken "-intensity" relation caused by the evolving photosphere emission and the nature of the extraordinarily bright GRB~230307A
GRB~230307A is one of the brightest gamma-ray bursts detected so far. With
the excellent observation of GRB~230307A by Fermi-GBM, we can reveal the
details of the prompt emission evolution. As found in high-time-resolution
spectral analysis, the early low-energy spectral indices () of this
burst exceed the limit of synchrotron radiation (), and gradually
decreases with the energy flux (). A tight
correlation anyhow holds within the whole duration of the burst, where is the spectral peak energy. Such evolution pattern of and with intensity is called ``double tracking". For the relation,
we find a log Bayes factor 210 in favor of a smoothly broken power-law
function over a linear function in log-linear space. We call this particular
relation as broken ``-intensity", and interpret it as the
evolution of the ratio of thermal and non-thermal components, which is also the
evolution of the photosphere. We also show that GRB 230307A with a duration of
, if indeed at a redshift of , is likely a neutron star
merger event (i.e., it is intrinsically ``short"). Intriguingly, different from
GRB 060614 and GRB 211211A, this long event is not composed of a hard spike
followed by a soft tail, suggesting that the properties of the prompt emission
light curves are not a good tracer of the astrophysical origins of the bursts.
The other possibility of would point toward very peculiar nature of
both GRB 230307A and its late time thermal-like emission.Comment: 14 pages, 6 figures, 1 table. We have excluded the GBM instrument
pile-up time interval in the data analysis and also discussed the nature of
this even
Recommended from our members
Water-Soluble Flexible Organic Frameworks That Include and Deliver Proteins.
Four water-soluble hydrazone-based three-dimensional (3D) flexible organic frameworks FOF-1-4 have been synthesized from a semirigid tetracationic tetraaldehyde and four flexible dihydrazides. 1H NMR spectroscopy indicated the quantitative formation of FOF-1-4 in D2O, while dynamic light scattering experiments revealed that, depending on the concentration, these porous frameworks display hydrodynamic diameters ranging from 50 to 120 nm. The porosity of the frameworks is confirmed by ethanol vapor adsorption experiments of the solid samples as well as the high loading capacity for a 2.3 nm porphyrin guest in water. The new water-soluble frameworks exhibit low cytotoxicity and form inherent pores with diameters of 5.3 or 6.7 nm, allowing rapid inclusion of proteins such as bovine serum albumin and green and orange fluorescent proteins, and efficient delivery of the proteins into normal and cancer cells. Flow cytometric analysis reveals percentages of the delivered cells up to 99.8%
Chronic stress induces steatohepatitis while decreases visceral fat mass in mice
BACKGROUND: Prolonged stress leads over time to allostatic load on the body and is likely to exacerbate a disease process. Long-term of stress exposure is one of a risk factor for metabolism-related diseases such as obesity and type 2 diabetes. However, the relationship between chronic stress and non-alcoholic fatty liver disease (NAFLD) remain unknown. METHODS: To address the hypothesis that chronic stress associate to NAFLD development, we subjected C57bl/6 mice to electric foot shock and restraint stress for 12 weeks to set up chronic stress model. Then the serum and hepatic triglyceride (TG), total cholesterol (TC) were measured. Hepatic HE and Oil red O staining were used to specify the state of the NAFLD. To investigate whether inflammation takes part in the stress-induced NAFLD process, related visceral fat, serum and hepatic inflammatory factors were measured. RESULTS: We observed that chronic stress led to an overall increase of hepatic triglyceride and cholesterol while decreasing body weight and visceral fat mass. Microvesicular steatosis, lobular inflammation and ballooning degeneration were seen in stress liver section. This effect was correlated with elevated hepatic and serum inflammatory factors. Although the amount of visceral fat was decreased in stress group, various adipocytokines were elevated. CONCLUSIONS: We showed that chronic stress is associated to NAFLD and chronic inflammation in visceral fat, though food intake and visceral fat mass were decreased. These results may contribute to better understanding of the mechanism from steatosis to steatohepatitis, and propose a novel insight into the prevention and treatment of NAFLD
- …