Oxidative stress and inflammation are hypothesized to contribute to the pathogenesis of chronic obstructive pulmonary disease (COPD). Resveratrol (trans-3,5,4'-trihydroxystilbene) is known for its ...antioxidant and anti-inflammatory properties. The study aimed to investigate the effects of resveratrol in a rat model with COPD on the regulation of oxidative stress and inflammation via the activation of Sirtuin1 (SIRTl) and proliferator-activated receptor-γ coactivator-1α (PGC-1α). Thirty Wistar rats were randomly divided into three groups: control group, COPD group and resveratrol intervention group. The COPD model was established by instilling with lipopolysaccharide (LPS) and challenging with cigarette smoke (CS). The levels of interleukin-6 (IL-6) and interleukin-8 (IL-8) in serum were measured. The levels of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) were measured. The expression levels of SIRT1 and PGC-1α in the lung tissues were examined by immunohistochemistry as well as real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR) and western blotting analysis. After the treatment with resveratrol (50 mg/kg), compared with the COPD group, alleviation of inflammation and reconstruction in the small airways of the lungs were seen. Resveratrol might be correlated not only with the lower level of MDA and the higher activity of SOD, but also with the upregulation of SIRT1 and PGC-1α expression. Resveratrol treatment decreased serum levels of IL-6 and IL-8. Our findings indicate that resveratrol had a therapeutic effect in our rat COPD model, which is related to the inhibition of oxidative stress and inflammatory response. The mechanism may be related to the activation and upgrading of the SIRT1/PGC-1α signaling pathways. Thus resveratrol might be a therapeutic modality in COPD.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Long-duration (>2 s) γ-ray bursts that are believed to originate from the death of massive stars are expected to be accompanied by supernovae. GRB 060614, that lasted 102 s, lacks a supernova-like ...emission down to very stringent limits and its physical origin is still debated. Here we report the discovery of near-infrared bump that is significantly above the regular decaying afterglow. This red bump is inconsistent with even the weakest known supernova. However, it can arise from a Li-Paczyński macronova--the radioactive decay of debris following a compact binary merger. If this interpretation is correct, GRB 060614 arose from a compact binary merger rather than from the death of a massive star and it was a site of a significant production of heavy r-process elements. The significant ejected mass favours a black hole-neutron star merger but a double neutron star merger cannot be ruled out.
Known for its high strength, ductility and durability, ultra-high performance concrete (UHPC) is a topic of interest in recent years for scientists and civil engineers. Great potential application of ...UHPC has driven increasingly more investments and research into this industry. In recent studies, taken advantage of the nanotechnology, novel UHPC material with nano material addition was developed. Great static performance improvement was observed when compared with normal strength concrete. To obtain full understanding of material properties, especially dynamic performance, Split-Hopkinson Pressure Bar (SHPB) tests were conducted on this new concrete material. For comparison purpose, static properties from uniaxial compression and split tensile tests are obtained and discussed. In this paper, effects of nanomaterials on behaviour of UHPC are assessed through group comparison. Dynamic increase factor (DIF) values for both the dynamic compressive strength and tensile strength are generated. It is found that the strength of UHPC increases with the rising of strain rates and dosage of nano material influences UHPC dynamic properties. However, UHPC is noted to be less rate sensitive comparing with normal strength concrete. Microscopy analysis including Scanning Electron Microscope (SEM) Analysis, X-Ray Diffraction (XRD) Analysis and X-Ray Fluorescence (XRF) Analysis are conducted to understand the macroscopic failure phenomenon, element composition and concrete hydration process.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•An innovative self-centering (SC) modular steel structure (MSS) connection is proposed.•Seismic behaviors of MSS and SC-MSS connections are investigated due to cyclic loadings.•SC-MSS connection ...exhibits better bearing capacity and self-centering capability.•SC haunch braces can reduce the plastic damage and improve the ductility of connection.
As an efficient and environment-friendly technique that combines off-site manufacturing of modules and on-site assembly, modular buildings have been adopted in many areas of the construction industry. This paper proposes an innovative modular steel structure (MSS) connection with bolted cover plates, which inserts a cross-shaped plug-in connector inside the adjacent columns to achieve accurate positioning in the module installation and provide partial shear capacity. A seismic retrofit method using hinged diagonal self-centering (SC) haunch braces is proposed for the MSS connection to improve the seismic performance and achieve functional recoverability after earthquakes. Hysteretic behaviors of the MSS connection and the self-centering MSS (SC-MSS) connection are investigated due to cyclic loadings. Results demonstrate that compared with the MSS connection, the SC-MSS connection is expected to improves strength and stiffness and exhibits stable flag-shaped hysteretic responses with a satisfactory self-centering capability. The hinged diagonal SC haunch braces are capable of reducing the average stress level around the connection core region, controlling the development of plastic damage, avoiding the local failure, and improving the ductility of connection. The present study provides practical connections and important guidance for the applications of modular steel structures in the medium- and high-intensity seismic regions.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A plug-in self-lock joint for modular steel construction is proposed.•Working mechanism is introduced and uplift behavior is verified through pull-out test.•Eight full-scale specimens are tested and ...seismic behavior is evaluated and discussed.•A simplified mechanical model is developed and validated through test results.
The joints between modular units are always key issues for modular steel construction. Previous types of joints require extra operation spaces for connection and will have conflicts with internal finish and installed services. Therefore, these types of joints cannot be adopted for middle columns in modular steel construction. Regarding this condition, a novel type of joint, plug-in self-lock joint was proposed in this study. The working mechanism of the plug-in self-lock connection was introduced, and a pull-out test was conducted to investigate the tensile behavior of the connection. Then eight full-scale joint specimens using the novel connection were tested under quasi-static load to investigate the seismic behavior of the plug-in self-lock joints. The test results offered failure mode, strength, stiffness, ductility and energy dissipation of the plug-in self-lock joints. Based on the experimental observation, a simplified mechanical model was developed to predict the behavior of this novel joint in elastic stage, and was validated through test results. Recommendations for the design of the joints were given accordingly.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We report a vinyl cyanation reaction of vinyl triflates and readily available 1,4‐dicyanobenzene through a nickel‐catalyzed reductive coupling process. The reaction is operated under mild conditions ...with remarkable functional‐group compatibility. Cyclic vinyl triflates with various ring sizes and substituents at different positions all reacted smoothly. The synthetic utility is demonstrated by the derivatization of pharmaceutical and natural compounds, a scale‐up synthesis, and various functional group transformations. Preliminary mechanistic studies demonstrate that vinyl triflates are more reactive than 1,4‐dicyanobenzene towards the oxidative addition to nickel catalyst.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Summary
The tracking performance of an actuation transfer system in a real‐time hybrid simulation (RTHS) frequently faces accuracy and robustness challenges under constraints and complicated ...environments with uncertainties. This study proposes a novel control approach based on the deep deterministic policy gradient algorithm in reinforcement learning (RL) combined with feedforward (FF) compensation, which emphasizes the implementation of shaking table control and substructure RTHS. The proposed method first describes the control plant within the RL environment. Then, the agent is trained offline to develop optimized control policies for interaction with the environment. A series of validation tests were conducted to assess the performance of the proposed method, starting with the dynamic testing of underwater shaking table control and then a virtual RTHS benchmark problem. For complex systems, such as controlling the underwater shaking table, the proposed algorithm, FF, and adaptive time series (ATS) compensation methods are compared under various water depths and motions. The results show better performance and wider broadband frequency applicability under different shaking table dynamic‐coupling effects. Next, a controller based on the proposed method was designed by extending the virtual RTHS via the configuration of the control plant and substructure division, as provided in the RTHS benchmark problem. The proposed RL controller also improved the tracking accuracy and robustness of conventional FF compensators against unmodeled dynamics and perturbation uncertainties. This controller can be extended to further advanced control strategies as a component of model‐based control methods.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We study the mass spectra and radiative decays of doubly heavy baryons within the diquark picture in a relativized quark model. The mass of the JP=1/2+ Ξcc ground state is predicted to be 3606 MeV, ...which is consistent with the mass of Ξcc++(3621) newly observed by the LHCb Collaboration. The predicted mass gap between two S-wave states, Ξcc* (JP=3/2+) and Ξcc (JP=1/2+), is 69 MeV. Furthermore, the radiative transitions of doubly heavy baryons are also estimated by using the realistic wave functions obtained from relativized quark model. The radiative decay widths of Ξcc*++→Ξcc++γ and Ξcc*+→Ξcc+γ are predicted to be about 7 and 4 keV, respectively. These predictions of doubly heavy baryons can provide helpful information for future experimental searches.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
The strong and radiative decay properties of the low-lying Ωc states are studied in a constituent quark model. We find that the newly observed Ωc states by the LHCb Collaboration can fit well in the ...decay patterns. Thus, their spin parity can possibly be assigned as the following: (i) Ωc(3000) has JP=1/2− and corresponds to the narrow 1P mixed state |1P2λ12−⟩1; its partner |1P2λ12−⟩2 should be a broad state with a width of ∼100 MeV. (ii) Ωc(3050) and Ωc(3066) can be assigned to be two JP=3/2− states, |1P4λ32−⟩ and |1P2λ32−⟩, respectively. (iii) Ωc(3090) can be assigned as the |1P4λ52−⟩ state with JP=5/2−. (iv) Ωc(3119) might correspond to one of the two 2S states of the first radial excitations, i.e., |2S2λλ12+⟩ or |2S4λλ32+⟩.
Full text
Available for:
CMK, CTK, FMFMET, IJS, NUK, PNG, UM
PDF
