Free gas accumulations in basal shear zones of mass-transport deposits (Pearl River Mouth Basin, South China Sea): An important geohazard on continental slope basins

Free gas is an important trigger of instability on continental slopes, and resulting mass-wasting strata can potentially form competent seals to hydrocarbon accumulations. This work uses two high-quality 3D seismic volumes to investigate fluid accumulations at the base of mass-transport deposits in the Pearl River Mouth Basin, South China Sea. In parallel, IODP/ODP borehole data are used to document the petrophysical character of mass-transport deposits formed in similar continental-slope environments to the South China Sea. The interpreted data show gas accumulations as comprising enhanced seismic reflections that are discordant, or vertically stacked, below mass-transport deposits with chaotic seismic facies. Gas was accumulated in basal shear zones of mass-transport deposits in response to differences in capillary pressure and porosity. Free gas in Zone A covers an area of at least 18 km2. In Zone B, the free gas is sub-circular in plan view and covers an area of 30.58 km2 for a volume of sediment approaching 1.5 km3. This work is important as it shows that vertical migration of gas is not significant in mass-transport deposits from the Pearl River Mouth Basin, but up-dip migration along their basal shear zones is suggested in multiple locations. As a result, free gas can pinch-out laterally to extend 1–2 km beyond these same basal shear zones. As a corollary, we show that free gas accumulations below mass-transport deposits comprise an important geohazard and should be taken into account when drilling continental-slope successions in both the South China Sea and continental margins recording important mass wasting. Strata charged with free gas form weak layers, hinting at a novel trigger of retrogressive slope failures on continental slopes worldwide

A New Wavelet Threshold Determination Method Considering Interscale Correlation in Signal Denoising

Due to simple calculation and good denoising effect, wavelet threshold denoising method has been widely used in signal denoising. In this method, the threshold is an important parameter that affects the denoising effect. In order to improve the denoising effect of the existing methods, a new threshold considering interscale correlation is presented. Firstly, a new correlation index is proposed based on the propagation characteristics of the wavelet coefficients. Then, a threshold determination strategy is obtained using the new index. At the end of the paper, a simulation experiment is given to verify the effectiveness of the proposed method. In the experiment, four benchmark signals are used as test signals. Simulation results show that the proposed method can achieve a good denoising effect under various signal types, noise intensities, and thresholding functions

Retrograde intrarenal surgery with intelligent control of renal pelvic pressure for staghorn calculi: a case report

Percutaneous nephrolithotomy is the gold standard treatment for staghorn calculi. However, this study reviews a case of an almost complete removal of staghorn calculi following one session of retrograde intrarenal surgery with intelligent control of renal pelvic pressure (RIRS-ICP). A 45 years-old female patient with an 8.3 × 4.5 cm complete staghorn stone was infected with Proteus mirabilis. Two sensitive antibiotics, piperacillin tazobactam and etimicin, were administered for 3 days. Semirigid 7/8.4 Fr ureteroscope was used to treat the renal pelvis and upper calyceal calculi for 57 min. A 550 μm holmium laser fiber with 2.0 J × 30 Hz was set. Next, a disposable flexible ureteroscope of 8.4 Fr was used to address residual middle and lower calyx stones for 94 min. A 200 μm holmium laser fiber with 1.0 J × 30 Hz was set. The renal pelvis pressure was controlled within 15 mmHg. A 2 mm CT scan on the first postoperative day showed inferior caliceal residue of approximately 1.0 × 0.6 cm. No complications occurred. This suggests that RIRS-ICP is a safe and effective treatment for staghorn calculi

Upregulation of Cellular Bcl-2 by the KSHV Encoded RTA Promotes Virion Production

Apoptosis of virus infected cells can restrict or dampen full blown virus propagation and this can serve as a protective mechanism against virus infection. Consequently, viruses can also delay programmed cell death by enhancing the expression of anti-apoptotic proteins. Human Bcl-2 is expressed on the surface of the mitochondrial membrane and functions as the regulator of the delicate balance between cell survival and apoptosis. In this report, we showed that the replication and transcription activator (RTA) encoded by KSHV ORF 50, a key regulator for KSHV reactivation from latent to lytic infection, upregulates the mRNA and protein levels of Bcl-2 in 293 cells, and TPA-induced KSHV-infected cells. Further analysis revealed that upregulation of the cellular Bcl-2 promoter by RTA is dose-dependent and acts through targeting of the CCN9GG motifs within the Bcl-2 promoter. The Bcl-2 P2 but not the P1 promoter is primarily responsive to RTA. The results of ChIP confirmed the direct interaction of RTA protein with the CCN9GG motifs. Knockdown of cellular Bcl-2 by lentivirus-delivered small hairpin RNA (shRNA) resulted in increased cell apoptosis and decreased virion production in KSHV-infected cells. These findings provide an insight into another mechanism by which KSHV utilizes the intrinsic apoptosis signaling pathways for prolonging the survival of lytically infected host cells to allow for maximum production of virus progeny