[en] The interactions of Cantharidin/Norcantharidin (CTD/NCTD) with two blood proteins, i.e., bovine serum albumin (BSA) and bovine hemoglobin (BHb), have been investigated by the fluorescence, UV–vis absorption, and FT-IR spectra under imitated physiological condition. The binding characteristics between CTD/NCTD and BSA/BHb were determined by fluorescence emission and resonance light scattering (RLS) spectra. The quenching mechanism of two blood proteins with CTD/NCTD is a static quenching. Moreover, the experimental data were further analyzed based on multivariate curve resolution-alternating least squares (MCR-ALS) technique to obtain the concentration profiles and pure spectra for three species (BSA/BHb, CTD/NCTD and CTD/NCTD–BSA/BHb complexes) which existed in the interaction procedure. The number of binding sites n and binding constants K_b were calculated at various temperatures. The thermodynamic parameters (such as, ΔG, ΔH, and ΔS) for BSA–CTD/NCTD and BHb–CTD/NCTD systems were calculated by the Van’t Hoff equation and also discussed. The distance r between CTD/NCTD and BSA/BHb were evaluated according to Förster no-radiation energy transfer theory. The results of Fourier transform infrared (FT-IR), synchronous fluorescence and three-dimensional fluorescence spectra showed that the conformations of BSA/BHb altered with the addition of CTD/NCTD. In addition, the effects of common ions on the binding constants of BSA–CTD/NCTD and BHb–CTD/NCTD systems were also discussed

[en] Magnetization of the compound LaFe_11.4Si_1.6 with the cubic NaZn₁₃-type structure was measured as functions of temperature and magnetic field around its Curie temperature T_C of ∼208 K. It is found that the magnetic phase transition at T_C is completely reversible. Magnetic entropy change ΔS, allowing one to estimate the magnetocaloric effect, was determined based on the thermodynamic Maxwell relation. The achieved magnitude of {vert-bar}ΔS{vert-bar} reaches 19.4 J/kgK under a field of 5 T, which exceeds that of most other materials involving a reversible magnetic transition in the corresponding temperature range. The large entropy change is ascribed to the sharp change of magnetization, which is caused by a large negative lattice expansion at the T_C. An asymmetrical broadening of {vert-bar}ΔS{vert-bar} peak with increasing field was observed, which is resulted from the field-induced itinerant-electron metamagnetic transition from the paramagnetic to ferromagnetic state above the T_C. [copyright] 2001 American Institute of Physics

[en] Objective: To analyze the diagnostic value of MRI, diffusion-weighted imaging (DWI) and ¹H-MR spectroscopy (¹H-MRS) in pediatric medulloblastoma histologic subtypes. Methods: The preoperative MRI (136), DWI (136) and ¹H-MRS (50) of 136 children with pathologically confirmed medulloblastomas were retrospectively analyzed. The mean ADC values (ADC_mean), minimum ADC values (ADC_min), tumor/normal brain ADC ratios (rADC) and metabolites were compared among the subtypes of medulloblastoma. Results: The histologic subtypes included 83 classic medulloblastomas (CMB), 28 desmoplastic medulloblastomas (DMB), 11 medulloblastomas with extensive nodularity (MB-EN), and 14 large cell or anaplastic medulloblastomas (LC/A). Conventional MRI manifestations including T₁ and T₂ signal intensities, contrast enhancement, peritumoral edema, cyst, hemorrhage, and dissemination were not significantly different among all histologic subtypes (P > 0.05). The ADC_mean, ADC_min and rADC of DMB was lower than that of CMB or LC/A whereas the ADC_mean, ADC_min and rADC of LC/A was highest among all histologic subtypes (P < 0.05). The ADC_mean, ADC_min and rADC were not significantly different between MB-EN and CMB or DMB (P > 0.05). The ADC_mean, ADC_min and rADC of LC/A medulloblastoma histologic subtype were greater than that of CMB whereas the ADC_mean, ADC_min and rADC of DMB were smaller than that of both LC/A and CMB. The ADC_mean, ADC_min and rADC were not significantly different between MB-EN and CMB or DMB. On ¹H-MRS, the ratios of choline (Cho)/creatine (Cr), the ratios of N-acetylaspartate (NAA)/Cr, NAA/Cho, myo-inositol (mI)/Cr and the presence of lipid were not significantly different among all histologic subtypes (P > 0.05) whereas lactate was significantly (P < 0.05) more common in LC/A than MB-EN followed by CMB and least common in DMB subtypes. Conclusion Conventional MRI manifestations, metabolite ratios and presence of lipid are not significantly different among medulloblastoma subtypes. The ADC_mean, ADC_min, rADC and presence of lactate varied significantly and are helpful in differential diagnosis of medulloblastoma subtypes. (authors)

[en] Objective: To investigate the influence of liver fat deposition on the quantification of the liver iron overload using fast-kilovolt-peak switching dual-energy CT imaging and material decomposition technique. Methods: A total of 20 healthy SD rats were taken to make 18 PVC tube of homogenate of fresh liver tissue. The dextran with concentration of 50, 40, 30, 20, 10 and 0 mg/ml were mixed with rat liver homogenate and triglyceride with three different concentrations (add fat with volume percentage of 60%, 30%, 10% and to simulate severe, moderate and mild fatty liver respectively). All samples were placed in standard phantom according to the order of iron concentration from high to low and scanned by GE Revolution CT 256 slices scanner in GSI mode with rapid tube voltage switching between 80 and 140 kVp and with tube current 200 mA, 320 mA, 485 mA respectively. The images of iron (fat)-based substance pair were reconstructed and the virtual iron concentration (VIC) value were recorded. The correlation between VIC and the actual liver concentration (LIC) of the three sets of tube currents (200, 320, 485 mA) was analyzed by Spearman correlation analysis and linear regression. Results: LIC and VIC were highly positively correlated with the liver iron deposition model under different tube currents (r value was 0.900 to 1.000, P < 0.05). The presence of fat will result in the decrease of VIC value. In a certain X-ray energy range and certain liver iron concentration, the higher the fat content, the more liver iron concentration underestimation were happened in VIC. At 200, 320 and 485 mA, the crossing points of linear equations for 30% and 10% fatty liver iron deposition models were located at VIC = 12.682, 12.470 and 13.447 mg/cm³, respectively. Conclusions: The fast-kilovolt-peak switching dual-energy CT imaging and material decomposition techniques can be used for quantitative evaluation of liver iron with hepatic steatosis. The presence of fat will lead to a decrease in VIC measurement. (authors)

[en] Very recently, via the covariant form of the adiabatic invariant I = ∮pidqi instead of I = ∫pidqi, an equally spaced spectroscopy of a Schwarzschild black hole was derived. The emphasis was given to the covariant of results. In this paper, we extend that work in a spherically symmetric spacetime to the case of a rotating Bañados—Teitelboim—Zanelli (BTZ) black hole. It is noteworthy that the adiabatic covariant action I = ∮pidqi gives the same value for the black hole spectroscopy in different coordinates. The result shows that the area spectrum is ΔA = 8πl²_P, which confirms Bekenstein's initial proposal. And the result is consistent with that already obtained by other methods. (general)

[en] Two-dimensional MoS₂ nanosheets were synthesized by using halloysite nanotubes (HNTs) as template under the hydrothermal synthesis. The structure and morphology of the as-synthesized MoS₂ nanosheets were determined by a series of characterizations. The results showed that the as-synthesized MoS₂ nanosheets were of the plate-like structure with about five layers, and the basal spacing was about 0.63 nm. It was demonstrated that HNTs played a crucial template role in the formation of the plate-like MoS₂ nanosheets. The formation mechanism was proposed. Furthermore, the tribological performance of the as-prepared MoS₂ nanosheets in oil was intensively examined on the ball-on-ball wear tester. The testing results verified that the as-prepared MoS₂ nanosheets as additive could significantly improve the friction performance of oil, which exhibited the good antifriction, antiwear, and load-carrying properties.

[en] The effect of a high pulsed magnetic field on the tensile properties and microstructure of 7055 alloy were investigated. In the tensile properties test, the pulsed magnetic field was applied to improve the tensile strength and elongation via the magnetoplasticity effect. The results show that when the magnetic induction intensity ( B ) is 3 T, the tensile strength and elongation arrives at the maximum synchronously, which has been enhanced by 7.9% and 20% compared to the relevant 576.5 MPa ( σ _b), 7.5% ( δ ) of the initial sample without magnetic field treatment. The high magnetic field takes effect by altering the spin state of free electrons stimulated between the dislocations and obstacles; afterwards, the structural state of the radical pair is converted from the singlet state with high bonding energy to the triplet state with low bonding energy. Under this condition, the dislocation mobility is enhanced and it becomes easier for a dislocation to surmount the obstacles. The residual stress in the sample is connected closely with the long distance stress generated from the dislocation behavior. At 3 T, the residual stress arrived at the minimum of 16 MPa. Moreover, in the presence of a magnetic field, the common η (MgZn₂) in the grain boundary dissolved and moved to internal grains because of the concentration difference, which helped to enhance the tensile strength and toughness of the materials. Finally, the fracture morphology was analyzed by scanning electronic microscopy. The fracture characteristic matches with the plasticity property. (paper)

[en] The properties of Ξ${}^{-<!--\; ???\; -->}$ hypernuclei are studied systematically using a two-dimensional Skyrme-Hartree-Fock approach combined with three different ΞN Skyrme forces fitted to reproduce the existing data. We explore the impurity effect of a single Ξ${}^{-<!--\; ???\; -->}$ hyperon on the radii, deformations, and density distributions of the nuclear core and point out qualitative differences between the different forces. We find that the Ξ${}^{-<!--\; ???\; -->}$ removal energy of ${}_{\mathrm{\Xi <!--\; ??\; -->}p}^{13}$B [${}^{12}$C(g.s.)+Ξ${}^{-<!--\; ???\; -->}$(1p)] calculated by the SLX3 force is 0.7 MeV, which is in good agreement with a possible value of 0.82±0.17MeV from the KEK E176 experiment. The theoretical prediction for this weakly bound state depends strongly on the deformation of the nuclear core, which is analyzed in detail.

[en] We study the laser-driven electron acceleration in a transversely inhomogeneous plasma channel. We find that, in inhomogeneous plasma channel, the developing of instability for electron acceleration and the electron energy gain can be controlled by adjusting the laser polarization angle and inhomogeneity of plasma channel. That is, we can short the accelerating length and enhance the energy gain in inhomogeneous plasma channel by adjusting the laser polarization angle and inhomogeneity of the plasma channel

[en] Based on the deformed Skyrme-Hartree-Fock (DSHF) approach, impurity effects of the Λ hyperons occupying p${}_{\mathrm{\Lambda <!--\; ??\; -->}}$ orbitals are studied systematically in this work. Properties of Λ and double-Λ hypernuclei with both even and odd numbers of nucleons, from light to heavy nuclear mass regions, are investigated. In our calculation, the Skyrme force, SkI4, is used for the NN interaction, while, for the NΛ interaction, two kinds of density-dependent forces are used, which are NSC89 and SLL4, respectively. In general, compared to observed binding energies, a Skyrme-type SLL4 interaction gives better predictions for p-shell region hypernuclei and heavy ones, while the microscopic NSC89 interaction is suitable for sd-shell hypernuclei for the s${}_{\mathrm{\Lambda <!--\; ??\; -->}}$ state and the p${}_{\mathrm{\Lambda <!--\; ??\; -->}}$ states. Through analysis of the density distributions and the energy curves of different configurations, we find that the Λ hyperons occupying the s${}_{\mathrm{\Lambda <!--\; ??\; -->}}$ orbital, [000]1/2${}^{+}$, make the density of nucleons more concentrated at the center and reduce the deformation of the nuclear core for light hypernuclei. It is also found that the Λ hyperons occupying the two p${}_{\mathrm{\Lambda <!--\; ??\; -->}}$ orbitals [110]1/2${}^{-<!--\; ???\; -->}$ and [101]3/2${}^{-<!--\; ???\; -->}$ drive the shapes of nuclear cores toward the prolate side and the oblate side, respectively, which is caused by the different distributions of the Λ hyperons on these two orbitals. The B(E2) values extracted from the DSHF calculation also support such conclusions. However, for the heavy hypernuclei, hyperons located on both s${}_{\mathrm{\Lambda <!--\; ??\; -->}}$ and p${}_{\mathrm{\Lambda <!--\; ??\; -->}}$ make little change on the nuclear core due to the saturation of its density distribution.