Application of Time-Fractional Order Bloch Equation in Magnetic Resonance Fingerprinting

Magnetic resonance fingerprinting (MRF) is one novel fast quantitative imaging framework for simultaneous quantification of multiple parameters with pseudo-randomized acquisition patterns. The accuracy of the resulting multi-parameters is very important for clinical applications. In this paper, we derived signal evolutions from the anomalous relaxation using a fractional calculus. More specifically, we utilized time-fractional order extension of the Bloch equations to generate dictionary to provide more complex system descriptions for MRF applications. The representative results of phantom experiments demonstrated the good accuracy performance when applying the time-fractional order Bloch equations to generate dictionary entries in the MRF framework. The utility of the proposed method is also validated by in-vivo study.Comment: Accepted at 2019 IEEE 16th International Symposium on Biomedical Imaging (ISBI 2019

Multiple shaking tables tests of seismic pounding effect of reinforced concrete bridge model

In order to investigate the longitudinal pounding effect of highway bridges with high-piers under strong ground motions, multiple shaking tables tests of a 1/10 scaled continuous rigid frame and simply-supported girder bridge with high-piers were carried out. The pounding responses of the bridge model under different earthquake excitations including the uniform excitation and the traveling wave excitation were studied, and the effectiveness of the dampers and isolation bearings for reducing the seismic pounding effect were analyzed and discussed. Test results indicate that the traveling wave effect is the important factor in seismic pounding response of high pier bridges. Additional dampers can mitigate the pounding effect apparently and play a role in reducing seismic response for bridge superstructures. Compared with conventional rubber bearing (RB), the decreases in the relative displacement and the pounding force between adjacent girders were 30 % and 55 % with lead rubber bearing (LRB) in this experiment, respectively. Seismic pounding effect of bridge superstructures depends on different structural dynamic properties of adjacent girders and characteristics of ground motions

A research on the policies to realise carbon intensity targets in China

In the context of carbon peaking and neutrality, it would be interesting to study the policy conditions for achieving carbon targets. From a technical perspective, this study constructed a theoretical model of the relationship between energy tax policy, R&D subsidy policy, and energy intensity within the framework of biassed technical change. Subsequently, through the logical relationship between energy and carbon intensities, three combination policy schemes for achieving the carbon intensity target were obtained. The findings are as follows: First, a higher rate of energy tax and R&D subsidy is destined to lead to a lower energy intensity, and energy tax policy can better boost energy intensity than R&D subsidy policy. Second, in terms of pulling the carbon intensity, the effect of the energy tax policy is better than that of the R&D subsidy policy, but in terms of its impact on the future policy effect, the R&D subsidy policy is better than the energy tax policy. Third, China should adopt a combination of policies to reduce carbon intensity, with a certain increase in the energy tax policy and a certain increase in the R&D subsidy rate policy

PO-097 The effect of 4 weeks intermittent negative pressure treatment on the functional state of excellent rowers

Objective To study the effect of intermittent negative pressure treatment on the functional state of elite rowers ,and providing theoretical basis for the application of this method in sports science. Methods The 15 elite male athletes selected from the national rowing training team were divided into experimental group and control group. The daily training plans of the two groups were the same. The members of experimental group were treated for 20 minutes by the Vacusport Regeneration System from German, five times one week, for a total of 4-weeks. The control group did not use any intervention. Before and after 4 weeks, venous blood from 15 male athletes was used to test athletes 'red blood cells(RBC), hemoglobin(HGB), hematocrit (HCT), creatine kinase(CK), blood urea nitrogen(BU), testosterone(T), cortisol(C) et, Observing the changes about data from two tests. Results There was no statistically significant difference between the experimental group and the control group before and after the intervention. The results of the intra-group comparison were as follows:(1) The RBC, HGB, and HCT of the experimental group decreased by 2.90 %, 3.80 %, and 1.08 % respectively. The RBC, HGB, and HCT of the control group decreased by 6.55 %, 7.02%, 4.03% respectively, and the decline of RBC and HGB showed statistically significant changes(p<0.05).（2）The CK and BU values of the experimental group increased by 1.26 % and 27.08 % respectively, and the increase of BU had statistically significant changes(p<0.05). The CK and BU values of the control group increased by 33.10 % and 9.54 % respectively. (3) The values of T, C and T / C in experimental group decreased by 11.85 %, 7.6 % and 4.31 % respectively. The values of T, C and T / C in the control group decreased by 16.38 %, 4.03 % and 19.39 % respectively, and the decrease of T values was statistically significant(p<0.05). Conclusions The intermittent negative pressure therapy can promote the athletes' metabolism, relieve the degree of the decline of functional state, and prevent the occurrence of fatigue

Hysteresis behavior of reinforced concrete bridge piers considering strength and stiffness degradation and pinching effect

In order to effectively simulate the nonlinear hysteresis behavior of reinforced concrete (RC) bridge piers under strong earthquake excitation, an improved nonlinear hysteresis model for RC bridge piers was developed and its controlling parameters were determined considering stiffness and strength degradation and pinching effect based on classical Bouc-Wen model. The improved model can be carried out to predict the nonlinear hysteresis behavior of RC bridge piers under various failure modes using MATLAB/ Simulink program. Cyclic tests of different failure mode bridge column specimens were performed under constant axial load with lateral bending. The results did show that force-displacement relationship curves of bridge column specimens derived from theoretical analysis agree well with experimental results. The nonlinear hysteresis behavior of bridge column specimen was simulated under 2008 Wenchuan earthquake excitation and its failure modes were identical with real earthquake damage of bridge column. The improved analytical models in the paper were applied to accurately predicting the nonlinear hysteresis behavior of RC bridge columns with strength and stiffness degradations and the pinching effect subjected to strong earthquake motion

The influence of phosphorus precursor on the structure and properties of SiO2-P2O5-CaO bioactive glass

Bioactive glasses (BGs) are one of the most promising bone regeneration materials because they can bond to bone and simulate new bone growth. Sol-gel methods for producing BG are well established, however challenges still remain in selecting and optimizing the precursors. Even for BGs with the same final composition, different precursors may lead to different structures and properties of the gel derived BG. In this work, three different phosphorus precursors, phytic acid (PA), triethyl phosphate (TEP) and n-butyl phosphate (BP) were used to prepareBG (54.2%SiO2-35%CaO-10.8%P2O5, mol%). The obtained materials were characterized by TGA, FTIR, XRD, HEXRD, solid state 31P, 29Si NMRand by in vitro tests in SBF. It was found that the materials prepared by TEP or BP showed small amounts of crystallization, whereas the resulting material prepared by PA remained amorphous and had more P atoms as orthophosphate. In vitro assays indicated that all these materials were bioactive, while the BG prepared by PA showed the highest in vitro bioactivity, followed by TEP and, finally, BP. Based on these observations, it appears that phosphorus precursors have a significant impact on both the structure and bioactivity of the sol-gel derived BG. Results suggest that PA should be used in preference to TEP or n-butyl phosphate for the synthesis of sol gels. PA may improve the homogeneity of the sol gel glasses, reduce crystallization and lower stabilization temperatures

Parameter-Saving Adversarial Training: Reinforcing Multi-Perturbation Robustness via Hypernetworks

Adversarial training serves as one of the most popular and effective methods to defend against adversarial perturbations. However, most defense mechanisms only consider a single type of perturbation while various attack methods might be adopted to perform stronger adversarial attacks against the deployed model in real-world scenarios, e.g., $\ell_2$ or $\ell_\infty$. Defending against various attacks can be a challenging problem since multi-perturbation adversarial training and its variants only achieve suboptimal robustness trade-offs, due to the theoretical limit to multi-perturbation robustness for a single model. Besides, it is impractical to deploy large models in some storage-efficient scenarios. To settle down these drawbacks, in this paper we propose a novel multi-perturbation adversarial training framework, parameter-saving adversarial training (PSAT), to reinforce multi-perturbation robustness with an advantageous side effect of saving parameters, which leverages hypernetworks to train specialized models against a single perturbation and aggregate these specialized models to defend against multiple perturbations. Eventually, we extensively evaluate and compare our proposed method with state-of-the-art single/multi-perturbation robust methods against various latest attack methods on different datasets, showing the robustness superiority and parameter efficiency of our proposed method, e.g., for the CIFAR-10 dataset with ResNet-50 as the backbone, PSAT saves approximately 80\% of parameters with achieving the state-of-the-art robustness trade-off accuracy.Comment: 9 pages, 2 figure

In vitro evaluation of a novel pH neutral calcium phosphosilicate bioactive glass that does not require preconditioning prior to use

It is well known that bioactive glasses can cause a significant increase in pH due to the rapid release of calcium and/or sodium ions. Consequently, preconditioning of the glass is usually required prior to surgery to negate the effect of this sudden release of ions. However, preconditioning for several days is far from ideal and also preconditioning is not practical for novel organic/inorganic sol-gel hybrids currently being developed since the organic phase will start to hydrolyze and dissolve. This study describes a bioactive glass that dissolves without causing a significant change in pH from physiologically optimal values and requires no preconditioning prior to use. The bioactivity of the pH neutral glass, hydroxyapatite formation, and cellular responses, are measured and compared directly with results from archetypal 45S5 and S70C30 bioactive glasses. A hydroxyapatite layer was found to rapidly form (within 1 day) on the surface of the pH neutral glass upon reacting with simulated body fluid. In addition, improved cell compatibility was observed compared with 45S5 and S70C30 glasses. Therefore, this pH neutral glass has significant potential for bone repair applications

Bioactive organic/inorganic hybrids with improved mechanical performance

New sol-gel functionalized poly-ethylene glycol (PEGM)/SiO2-CaO hybrids were prepared with interpenetrating networks of silica and PEGM through the formation of Si-O-Si bonds. Bioactive and mechanical properties were investigated for a series of hybrids containing varying organic/inorganic ratios and PEG molecular weights. In contrast to the unmodified PEG/SiO2-CaO hybrids, which rapidly dissolved and crumbled, the epoxy modified hybrids exhibited good mechanical properties and bioactivity. The compressive strength and Young's modulus were greater for higher molecular weight PEGM hybrids (PEGM600 compared to PEGM300). Compressive strengths of 138 MPa and 81 MPa were found for the 50: 50 and 60: 40 organic/inorganic hybrid samples respectively, which are comparable with cortical bone. Young's modulus values of ∼800 MPa were obtained for the 50 : 50 and 60 : 40 organic/inorganic hybrids. Bioactivity tests were conducted by immersing the hybrids into simulated body fluid and observing the formation of apatite. Apatite formation was observed within 24 hours of immersion. PEGM600 hybrids showed enhanced apatite formation compared to PEGM300 hybrids. Increased apatite formation was observed with increasing organic/inorganic ratio. 70 : 30 and 60 : 40 hybrids exhibited the greatest apatite formation. All PEGM hybrids samples had good cell viability and proliferation. The 60 : 40 PEGM600 hybrids displayed the optimal combination of bioactivity and mechanical strength. The bioactivity of these hybrids, combined with the enhanced mechanical properties, demonstrate that these materials have significant potential for bone regeneration applications