Effect of Hydrofluoric Acid Etching on Performance of Si/C Composite as Anode Material for Lithium-Ion Batteries

The effect of hydrofluoric acid (HF) etching on the performance of Si/C anode was extensively studied in terms of the structural stability, morphology, element distribution, and electrochemical properties. XRD results show that the diffraction peaks of silicon got weakened after being etched by HF. SEM images reveal that the morphology of the composite became coarse after being etched by HF. EDS mapping illustrates the distribution of elements before and after HF etching. Electrochemical studies show that HF etching can improve the cycling performance of Si/C composite but exhibit a deleterious effect on capacity. The results indicate that HF etching could be a promising method for enhancing the performance of silicon-based materials

Theory of AdaDelSPGD Algorithm in Fiber Laser-Phased Array Multiplex Communication Systems

Stochastic parallel gradient descent (SPGD) algorithm is one of the most promising methods for effective coherent beam combination. However, the algorithm also has some disadvantages, such as slow convergence speed and local extremum. This paper proposes an AdaDelSPGD algorithm, which combines an AdaDelta algorithm with a SPGD algorithm, and improves the traditional AdaDelta algorithm with adaptive gain coefficient. It is worth noting that the adaptive gain coefficient can be adjusted in real time to improve the convergence rate. The effectiveness of the proposed algorithm is verified by relevant simulation experiments, and the results show that the proposed algorithm can significantly improve the convergence speed. Following the experiments with the fiber laser-phased array multiplex communication system, we can draw the conclusion that the addition of communication modulation reduces the beam quality, and the higher the modulation frequency, the worse the beam quality. However, adding the SPGD algorithm can improve the beam quality. The AdaDelSPGD algorithm proposed in this paper can further improve the beam quality, and the bit error rate of communication is also decreased after testing. This provides a foundation for further research on the fiber laser-phased array multiplex communication system

Real-Time and Robust Compressive Background Subtraction for Embedded Camera Networks

Real-time target tracking is an important service provided by embedded camera networks. The first step in target tracking is to extract the moving targets from the video frames, which can be realised by using background subtraction. For a background subtraction method to be useful in embedded camera networks, it must be both accurate and computationally efficient because of the resource constraints on embedded platforms. This makes many traditional background subtraction algorithms unsuitable for embedded platforms because they use complex statistical models to handle subtle illumination changes. These models make them accurate but the computational requirement of these complex models is often too high for embedded platforms. In this paper, we propose a new background subtraction method which is both accurate and computationally efficient. We propose a baseline version which uses luminance only and then extend it to use colour information. The key idea is to use random projection matrics to reduce the dimensionality of the data while retaining most of the information. By using multiple datasets, we show that the accuracy of our proposed background subtraction method is comparable to that of the traditional background subtraction methods. Moreover, to show the computational efficiency of our methods is not platform specific, we implement it on various platforms. The real implementation shows that our proposed method is consistently better and is up to six times faster, and consume significantly less resources than the conventional approaches. Finally, we demonstrated the feasibility of the proposed method by the implementation and evaluation of an end-to-end real-time embedded camera network target tracking application

Construction and in vitro characterization of dual-modality single-photon emission computed tomography-MRI nanoprobes targeting HAb18G/CD147 in breast tumors

Objective: To prepare dual-modality single-photon emission computed tomography (SPECT)-MRI molecular nanoprobes targeting HAb18G/CD147 expressed on breast cancer cell membranes and investigate the physicochemical and biological properties in vitro. Methods: Superparamagnetic iron oxide nanoparticles (SPIOs) were prepared by one-pot reaction method as described. The single-chain antibody fragments HAbF18(ab')2 were conjugated to SPIOs via chemical method and then labeled with 125I using Iodogen method. The final 125I-SPIO-HAbF18(ab')2 nanoprobes were purified. SPIOs or 125I-HAbF18(ab')2 were used as control. We carried preliminary evaluation on their physicochemical properties and biological characteristics in vitro: transmission electron microscope (TEM) and dynamic light scattering (DLS) were used to measure these nanoparticle sizes and the hydrodynamic diameters. The MRI T2 transverse relaxation efficiency of these nanoprobes at different Fe2+ concentrations were measured with 1.5 T clinical MR scanner. The 125I-SPIO-HAbF18(ab')2 and 125I-HAbF18(ab')2 radiochemical purity were measured by thin layer chromatography and the radio chemical yield was calculated. We also conducted stability tests in vitro and octanol/water partition coefficient experiments. Two breast tumor cell lines, MDA-MB-231 (HAb18G-overexpressing cells,experimental group) and MDA-MB-468 (control), were used for assessment of cells viability at different Fe2+ concentrations (1, 5, 10, 20, 40 μg/ml) by methyl thiazolyl tetrazolium assay. Specific binding experiments in vitro included two parts:magnetic resonance imaging and radionuclide tests, the above-mentioned breast cancer cell lines were incubated with 125I-SPIO-HAbF18(ab')2 nanoprobes respectively and took MDA-MB-231 cells which were not treated as blank group. First comparing the MR signal intensity differences among experimental group, the control group and blank group, then calculated the rate of MRI signal changes; Two breast tumor cell lines, MDA-MB-231 and MDA-MB-468 were incubated with 125I-SPIO-HAbF18(ab')2 nanoprobes too, then measured radioactivity counting by γ counter at different time and calculated the cell binding rates, and did statistical analysis by using one-way ANOVA. Results: The SPIOs were fairly homogeneous with an average core size of (10.32±1.30) nm;the SPIO and 125I-SPIO-HAbF18(ab')2 hydrodynamic diameter of 44.80 and 52.64 nm, and MRI scanning showed that the transverse relaxation efficiency of SPIO and 125I-SPIO-HAbF18(ab')2 were 38.79 and 106.73 mM-1 · s-1, respectively. The radio chemical yield of 125I-SPIO-HAbF18(ab')2 and 125I-HAbF18(ab')2 were 41.90% and 85.50%, respectively. The radio chemical yield of the two groups were >95%, suggesting well stability in vitro. The lipo-hydro partition coefficient values were -0.99 ± 0.03 and-1.49 ± 0.08, respectively, which demonstrated that they were both water-soluble substances. Different Fe2+ concentrations (1,5,10,20,40μg/ml) of 125I-SPIO-HAbF18(ab')2 on breast cancer cell lines MDA-MB-231 and MDA-MB-468 showed no significant inhibition of cell proliferation (F values were 0.78, 0.66; P values were 0.58, 0.66). The cell-specific binding experiment showed: MRI signal intensity values on experimental group, the control group and the blank group were (1 670 ± 5), (1 930 ± 8), (2 349 ± 14), respectively, significant differences existed among these groups (F=4 408.48, P=0.000), the rate of signal intensity change of experimental group and the control group were 28.87%, 17.78%. SPECT:MDA-MB-231 could uptake 125I-SPIO-HAbF18(ab')2, the cell binding rates were (6.52 ± 0.60)% and (10.52 ± 2.04)% in 20 min and 4 h, respectively. Conclusions: Our results suggested that the dual-modality SPECT-MRI nanoprobes 125I-SPIO-HAbF18(ab')2 were prepared successfully with good physicochemical properties and biological characteristics in vitro. These dual-modality molecular imaging nano-probes may have potential to improvearly detection and diagnosis of HAb18G/CD147-expressing cancers and to facilitate the development of HAb18G/CD147-directed interventions

FGF19 increases mitochondrial biogenesis and fusion in chondrocytes via the AMPKα-p38/MAPK pathway

Abstract Fibroblast growth factor 19 (FGF19) is recognized to play an essential role in cartilage development and physiology, and has emerged as a potential therapeutic target for skeletal metabolic diseases. However, FGF19-mediated cellular behavior in chondrocytes remains a big challenge. In the current study, we aimed to investigate the role of FGF19 on chondrocytes by characterizing mitochondrial biogenesis and fission–fusion dynamic equilibrium and exploring the underlying mechanism. We first found that FGF19 enhanced mitochondrial biogenesis in chondrocytes with the help of β Klotho (KLB), a vital accessory protein for assisting the binding of FGF19 to its receptor, and the enhanced biogenesis accompanied with a fusion of mitochondria, reflecting in the elongation of individual mitochondria and the up-regulation of mitochondrial fusion proteins. We then revealed that FGF19-mediated mitochondrial biogenesis and fusion required the binding of FGF19 to the membrane receptor, FGFR4, and the activation of AMP-activated protein kinase alpha (AMPKα)/peroxisome proliferator-activated receptor-gamma coactivator 1 alpha (PGC-1α)/sirtuin 1 (SIRT1) axis. Finally, we demonstrated that FGF19-mediated mitochondrial biogenesis and fusion was mainly dependent on the activation of p-p38 signaling. Inhibition of p38 signaling largely reduced the high expression of AMPKα/PGC-1α/SIRT1 axis, decreased the up-regulation of mitochondrial fusion proteins and impaired the enhancement of mitochondrial network morphology in chondrocytes induced by FGF19. Taking together, our results indicate that FGF19 could increase mitochondrial biogenesis and fusion via AMPKα-p38/MAPK signaling, which enlarge the understanding of FGF19 on chondrocyte metabolism. Video Abstrac