[en] Objective: To investigate the value of apparent diffusion coefficient (ADC) of breast carcinoma before and one course after neoadjuvant chemotherapy, and to predict the response of breast carcinoma to neoadjuvant chemotherapy. Methods: Twenty female patients with 21 breast carcinoma lesions were examined with diffusion weighted imaging (DWI) and contrast-enhanced MRI within 7 days prior to neoadjuvant chemotherapy (adriamycin + taxinol), during 18-21 days after the first couse of therapy and within 7 days prior to the surgery resection. The tumors were divided into response group and relative nonresponse group by change of the tumor. The difference of ADC between the two groups before and after 1st course of chemotherapy was compared. Results: In chemotherapy response group with 15 lesions, the mean ADC was (0.98±0.15) x 10^-3 mm²/s before chemotherapy and increased to (1.22 ± 0.23) x 10^-3 mm²/s after 1 st course of chemotherapy (P<0.05), while in nonresponse group with 6 lesions, the mean ADC before and after chemocherapy was (1.09±0.08) x 10^-3 mm²/s and (1.11±0.07) x l0^-3 mm²/s, respectively, with no statistical difference( P>0.05). The mean ADC of response group prior to chemotherapy was significantly lower than that of nonresponse group (P<0.05). A significant negative correlation (r=-0.51, P<0.05) was observed between the ADC prior to treatment and change of ADC after the first couse therapy. Conclusion: Preliminary results revealed the initial ADC of the tumor in patient with breast carcinoma and the changes of ADC after 1st couse treatment may predict response to neoadjuvant chemotherapy. (authors)

[en] In this paper, we consider the optimal control problem for the mean-field stochastic differential equations with delay and state constraint. By virtue of the classical Ekeland’s variational principle, the duality method and a new type of mean-field anticipated backward stochastic differential equation, we obtain the maximum principle of the optimal control for this problem. Our result can be applied to a harvest model from a mean-field system with delay.

[en] Objective: To evaluate the response of the lung tumor xenografts in nude mice to antiangiogenic treatment from perspectives of anatomic, vessel function, cellular and molecular level using the multimodality imaging techniques including optical imaging, dynamic contrast enhanced MRI (DCE-MRI) and diffusion weighted imaging (DWI). Methods: The green fluorescent protein (GFP) was transplanted labeled using GFP-expressing NCI-H460 cells. After the transfection of GFP, NCI-H460 cells were implanted subcutaneously into nude mice. Ten days after implantation, 12 nude mice whose tumor xenografts grew to 0.5-1.0 cm in the maximum diameter were randomly divided into 2 groups, and injected with phosphate-buffered saline and recombinant human endostatin respectively. Then the nude mice in the two groups underwent optical imaging, DCE-MRI and DWI. The volumes, photon counts, the quantitative MR vessel functional parameters including volume transfer constant (K"t"r"a"n"s), rate constant (K_e_p), volume of extravascular extracellular space (V_e) and maximum area under the enhancement curve (iAUC), and apparent diffusion coefficient (ADC) values of the tumors were recorded. Then tumors were collected and observed using the transmission electron microscopy and pathology examination, including HE staining, microvessel density (MVD) and the expressions of vascular endothelial cell growth factor (VEGF). The K_e_p and VEGF expressions in experimental group and control group were compared with χ"2 text, and other values were compared with t test. The Pearson and Spearman test were used for analyzing the correlation of values in the two groups. Results: Seven days after inoculation, the fluorescence signals were detected and grew with the growth of the tumors. On the 7 day after starting therapy, the photon counts of experimental group and control group were (2.51 ± 2.43)× 10"1"0 (photon/sec) and(5.77 ± 3.25)× 10"1"0 (photon/sec), respectively with no significant differences (t=1.964, P >0.05). Two sample t test showed that the tumor volumes in experimental group were smaller than those in control group [(365 ± 56)vs(987 ± 265)mm"3, t=0.001, P<0.01]. There was a positive correlation (r=0.673, P<0.05) between the photon counts and the volumes of the tumors. The mean K"t"r"a"n"s, K_e_p, V_e and iAUC of experimental group were: (0.055 ±0.012)min"-"1, 0.335 (0.184-0.894)min"-"1, 0.297 ± 0.041 and 7.334 ± 3.930, and those for control group were: (0.117 ± 0.027)min"-"1, 0.417(0.324-1.736)min"-"1, 0.326±0.062 and 13.280 ± 4.245. There were significant differences of K"t"r"a"n"s and iAUC (t=5.155, 2.518, P<0.05) between experimental group and control group. And there was a positive correlation (r=0.715, P<0.0 1) between the values of iAUC and MVD, but not the expressions of VEGF (r=0.484, P>0.05). The values of ADC in experimental group were higher than that in control group [(791 ± 38)× 10"-"6 vs (737 ± 43)×10"-"6 mm"2/s], and there were significant differences (t=-2.299, P<0.05). Two sample t test showed that the MVD in experimental group were lower than that in control group [(11.9 ± 4.8) vs (19.2 ±4.3)item/hpf, t=2.774, P<0.05]. The VEGF expressions in experimental group were lower than that in control group (χ"2=4.000, P>0.05). It was observed that some cells in experimental group had degenerated and apoptotic signs by the electron microscopy. Conclusions: Evaluating the response of lung tumor xenografts to antiangiogenic treatment at anatomical, vessel functional, cellular and molecular level using the multimodality imagings is applicable. And it will be in favour of evaluating the therapeutic effect promptly. (authors)

[en] In this article, localized linear defect modes due to band gap guidance in two-dimensional photonic lattices with localized or nonlocalized defects are investigated theoretically. First, when the defect is localized and weak, eigenvalues of defect modes bifurcated from edges of Bloch bands are derived analytically. It is shown that in an attractive (repulsive) defect, defect modes bifurcate out from Bloch-band edges with normal (anomalous) diffraction coefficients. Furthermore, distances between defect-mode eigenvalues and Bloch-band edges decrease exponentially with the defect strength, which is very different from the one-dimensional case where such distances decrease quadratically with the defect strength. It is also found that some defect-mode branches bifurcate not from Bloch-band edges, but from quasiedge points within Bloch bands, which is very unusual. Second, when the defect is localized but strong, defect modes are determined numerically. It is shown that both the repulsive and attractive defects can support various types of defect modes such as fundamental, dipole, quadrupole, and vortex modes. These modes reside in various band gaps of the photonic lattice. As the defect strength increases, defect modes move from lower band gaps to higher ones when the defect is repulsive, but remain within each band gap when the defect is attractive, similar to the one-dimensional case. The same phenomena are observed when the defect is held fixed while the applied dc field (which controls the lattice potential) increases. Lastly, if the defect is nonlocalized (i.e., it persists at large distances in the lattice), it is shown that defect modes can be embedded inside the continuous spectrum, and they can bifurcate out from edges of the continuous spectrum algebraically rather than exponentially

[en] Ultrasonic additive manufacturing (UAM) is an advanced additive manufacturing technique that utilizes ultrasonic energy to rapidly joining thin metal tapes into solid parts in a layer accumulating manner. In this study, the effects of processing parameters on the bond properties of UAM samples were investigated via peel tests, linear weld density (LWD) measurements, microhardness tests and EBSD. The results reveal that, in terms of the overall tendency, the peeling strength and LWD increase with the increasing amplitude and normal force settings. However, a parameter threshold phenomenon and two different mechanisms that affect the bond properties were also observed. Furthermore, the microstructure evolution results show that the development of the interface is closely related to the applied parameters, which can also well explain the bond property variations and the parameter threshold phenomenon. (paper)

[en] In this paper, a novel NiTi shape memory alloy fiber reinforced Mg3AlZn (SMAFR-AZ31) composite sheet was successfully fabricated by laminate structure design combined with hot pressing method using Mg3AlZn (AZ31) foils and continuous NiTi shape memory alloy fibers. The interfacial microstructure of the SMAFR-AZ31 composite sheet was systematically characterized by a high resolution transmission electron microscopy (FEI-TEM Talos F100) combined with an FEI Helios 600i focused ion beam/scanning electron microscopy (FIB/SEM) system. The normal tensile strength of the SMAFR-AZ31 composite sheet was tested using a novel direct tensile sample configuration with the tensile direction perpendicular to prior AZ31 foils. Results showed that a well-densified AZ31 matrix and uniformly distributed NiTi fiber reinforcements were obtained in the SMAFR-AZ31 composite sheet after hot pressing. A continuous interfacial reaction layer consisting of nanocrystalline-amorphous mixture and a few intermetallic phases were formed around the NiTi_f/AZ31 interface. The nanocrystalline was identified as dual phase coexistence grains of MgO and TiO₂, and the amorphous phase was a mixture of Mg–Ti–O and Mg–O. A newly Ti₂Ni intermetallic phase that obeys a specific orientation relationship with NiTi fiber ($\left[\bar{4}2\bar{1}\right]$ NiTi// $\left[\bar{1}12\right]$ Ti₂Ni, (132) NiTi// $\left(1\bar{1}1\right)$ Ti₂Ni with an angle difference of 6.27°) precipitated adjacent to the interface reaction layer. A Ni-rich intermetallic phase identified as AlNi formed at the NiTi_f/AZ31 interface. Furthermore, it is found that large plastic deformation occurred near the interface reaction region in the AZ31 matrix, which is responsible for the successful embedding of NiTi fibers. Compared with the AZ31 laminate sheet without NiTi fibers, the SMAFR-AZ31 composite sheet possessed a superior normal tensile strength, which is attributed to the formation of the amorphous phase at the NiTi_f/AZ31 interface.

[en] Objective: To compare the efficacies of MRI, X-ray mammography (XMG) and Ultrasound (US) in detecting and diagnosing breast ductal carcinoma in situ (DCIS). Methods: Two hundred and forty one consecutive patients with pathology-confirmed DCIS were retrospectively recruited from January 2011 to December 2017 in PLA General Hospital. The imaging examination modalities included MRI and/or XMG and/or US. The breast imaging reporting and data system (BI-RADS) categorizations by MRI, XMG and US were compared and their sensitivities of detecting DCIS were calculated. The causes of underestimation on MRI were interpreted with the information of XMG and US. Chi-square test was used to compare the differences. Results: The diagnostic sensitivity of XMG, US and MRI was 65.9% (29/44), 71.6% (101/141) and 91.2% (145/159), respectively, with statistical significant differences (X² = 24.034, P < 0.001). Breast density and lesion type would influence the sensitivity of XMG. And the sensitivity of US was decreased because of non-mass lesion. Of the 14 cases under-evaluated as BI-RADS category 1 to 3 on MRI, 5 were corrected by XMG and/or US to BI-RADS category 4. The cause of underestimation on MRI was the coexistence of DCIS with adenoma or other benign lesion. Conclusion: The retrospective comparison of MRI, XMG and US in this study showed that MRI had significant higher sensitivity in detecting breast DCIS, while the false negative rates of XMG and US were un-negligible. (authors)

[en] Driven by a rapid increase of energy consumption and emerging pollution control policies, air pollutant emissions have changed dramatically in China during 2005–2010. This study developed a multi-pollutant emission inventory, and used the community multi-scale air quality (CMAQ) modeling system to evaluate the impact of the emission changes on particulate matter pollution and soil acidification. During 2005–2010, the emissions of SO₂, PM₁₀ and PM_2.5 decreased by 14.9%, 15.1% and 11.7%, respectively. In contrast, the emissions of NO_X, NMVOC and NH₃ increased by 33.8%, 21.0% and 10.4%, respectively. The emission trends differed notably in different regions. Driven by emission changes, PM_2.5 concentrations decreased by 2–17 μg m⁻³ in most of the North China Plain, the Yangtze River Delta and the Pearl River Delta, while increasing by 4.5–16 μg m⁻³ in most of the Sichuan Basin and Eastern Hubei. The changes of PM_2.5 emissions led to the decline of primary PM_2.5 concentrations in most of Eastern China. As an effect solely of emission changes, nitrate concentrations increased across most of China; sulfate concentrations decreased in most of Eastern China, with the largest reduction in the North China Plain, while they increased in the Sichuan Basin and parts of the Pearl River Delta and Eastern Hubei. The concentrations of secondary inorganic aerosols (SIA) and the extinction coefficient increased in most of China, especially in the Sichuan Basin and Eastern Hubei, implying that the NO_X and NH₃ emissions should be reduced simultaneously in China. Combining the acidification effects of S and N, the exceedance of critical loads decreased across the country, but increased in the Sichuan Basin, the Pearl River Delta and Eastern Hubei, where the soil acidification was the most serious. Different control policies need to be implemented in different regions. (letter)

[en] We study various families of lattice solitons supported by competing cubic-quintic nonlinearity, in the framework of NLSE with periodic potential. For the first time to our knowledge, we found 'multi-stable' states in the semi-infinite gap. Linear stability analysis and numerical simulation show that some lattice solitons in the semi-infinite gap are stable, while some are unstable, but they do not radiate. Lattice solitons in higher gaps are unstable except for those single-humped solitons (even symmetry) and two-humped solitons (odd symmetry) with their eigenvalue close to the left band of the gap they reside in

[en] The ER321 stainless steel was fabricated by laser and wire additive manufacturing (LWAM) assisted with ultrasonic vibration (UV) under synchronous motion conditions. It was found that the grain structure of ER321 stainless steel varied from coarse columnar dendrites (without UV) to equiaxed dendrites (with UV). And, the UV effectively weakened the texture strength and homogenized the grain structure of the deposition layers. The improvement of grain structure enhanced the microhardness (~10.7%) and yield strength (~11.9%) of ER321 stainless steel. These results show that this innovative manufacturing approach can effectively improve the problem of coarse columnar dendrites in the additive manufactured complex large-scale components.