Background: The bridge exercise targets the gluteus maximus (Gmax) and gluteus medius (Gmed). However, there is also a risk of dominant hamstring (HAM) and erector spinae (ES) muscles. Objects: To analyze the muscle activity the of Gmax, Gmed, HAM and ES during the bridge exercise with and without hip external rotation in different degrees of knee flexion. Methods: Twenty-three subjects were participated. The electormyography (EMG) activity of the Gmax, Gmed, HAM and ES muscles was recorded during the exercise. The subjects performed the bridge exercise under four different conditions: (a) with 90˚ knee flexion, without hip external rotation (b) with 90˚ knee flexion, with hip external rotation (c) with 135˚ knee flexion, without hip external rotation (d) with 135˚ knee flexion, with hip external rotation. Results: There was no significant interaction effect between the degree of knee flexion and hip external rotation. There was a significant main effect for degree of knee flexion in Gmax, HAM muscles activity. Gmax muscle activity was significantly greater in the 135˚ knee flexion position than in the 90˚ knee flexion position (p<.001). While HAM muscle activity was significantly less in 135˚ knee flexion position than in the 90˚ knee flexion position (p<.001). ES muscle activity was significantly less in the 135˚ knee flexion position than in the 90˚ knee flexion position (p=.002). The activity of both the Gmax and Gmed muscles was significantly greater with hip external rotation (p<.001 and p=.005, respectively). Conclusion: For patients performing the bridge exercise, positioning the knee in 135° of flexion with hip external rotation is effective for improving Gmax and Gmed muscle activity while decreasing HAM, and ES muscle activity.

While the reverberation mapping technique is the best available method for measuring black hole mass in active galactic nuclei (AGNs) beyond the local volume, this method has been mainly applied to relatively low-to-moderate luminosity AGNs at low redshift. We present the strategy of the Seoul National University AGN Monitoring Project, which aims at measuring the time delay of the Hβ line emission with respect to AGN continuum, using a sample of relatively high luminosity AGNs out to redshift z ∼ 0.5. We present simulated cross correlation results based on a number of mock light curves, in order to optimally determine monitoring duration and cadence. We describe our campaign strategy based on the simulation results and the availability of observing facilities. We present the sample selection, and the properties of the selected 100 AGNs, including the optical luminosity, expected time lag, black hole mass, and Eddington ratio.

Structural characterization of pyrolysis fuel oil (PFO) was conducted via 1H NMR and 13C NMR to elucidate its molecular structure and evaluate the feasibility of using PFO as a raw material for mesophase pitch synthesis. The average structural parameters were calculated based on the data from elemental analysis and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), as well as 1H NMR and 13C NMR data. The resultant structural features of PFO were compared with those of fluidized catalytic cracking-decant oil (FCC-DO). Based on the calculated parameters, we proposed average molecular models of PFO and FCC-DO. The molecular model of PFO showed that it had an aromatic structure consisting of three aromatic rings and one naphthenic ring fused with one pericondensed and two catacondensed aromatic carbons, as well as a short alkyl side chain (with only a methyl group). This structural feature of PFO demonstrated that it is highly favorable for use as a raw material for mesophase pitch synthesis. The empirical findings in this study provide an in-depth understanding of the molecular structure of PFO as well as FCC-DO and can offer insights for future research on the utilization of PFO and other petroleum heavy oils.