Experimental Investigation of Low-Frequency Distributed Acoustic Sensor Responses to Two Parallel Propagating Fractures.

Low-frequency distributed acoustic sensing (LF-DAS) is a diagnostic tool for hydraulic fracture propagation with far-field monitoring using fiber optic sensors. LF-DAS senses strain rate variation caused by stress field change due to fracture propagation. Fiber optic sensors are installed in the monitoring wells in the vicinity of a fractured well. From the strain responses, fracture propagation can be evaluated. To understand subsurface conditions with multiple propagating fractures, a laboratory-scale hydraulic fracture experiment was performed simulating the LF-DAS response to fracture propagation with embedded distributed optical fiber strain sensors under these conditions. The experiment was performed using a transparent cube of epoxy with two parallel radial initial flaws centered in the cube. Fluid was injected into the sample to generate fractures along the initial flaws. The experiment used distributed high-definition fiber optic strain sensors with tight spatial resolutions. The sensors were embedded at two different locations on opposite sides of the initial flaws, serving as observation/monitoring locations. We also employed finite element modeling to numerically solve the linear elastic equations of equilibrium continuity and stress-strain relationships. The measured strains from the experiment were compared to simulation results from the finite element model. The experimentally derived strain and strain-rate waterfall plots from this study show the responses to both fractures propagating, while the fracture at the lower position took most of the fluid during the experiment. Interestingly, a fracture first began propagating from the upper flaw of the two flaws, but once the lower fracture was initiated, it grew much faster than the upper fracture. Both fibers were intercepted by the lower fracture, further verifying the strain signature as a fracture is approaching and intersecting an offset fiber.

Protective role of LRRC3B in preventing breast cancer metastasis and recurrence post-bupivacaine.

The present study aimed to investigate the potential effect of leucine-rich repeat containing 3B (LRRC3B) with respect to the inhibition of breast cancer recurrence and metastasis post-anesthesia. The mRNA expression of LRRC3B in breast MDA-MB-231 and MCF-7 cell lines was detected using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis. The effect of bupivacaine on breast cancer cell invasion was analyzed using a Matrigel assay. LRRC3B specific small interfering (si)RNA was constructed and transfected into breast cancer cells using Lipofectamine® 2000 reagent. The influence of bupivacaine on LRRC3B expression was measured based on RT-qPCR. Additionally, the effect of LRRC3B silencing on the invasion of breast cancer cells treated with bupivacaine was analyzed. Compared with the control, LRRC3B expression significantly increased in MDA-MB-231 and in MCF-7 cells as the length of time increased (P<0.05), but the expression of the gene significantly declined in 2 types of cancer cell when the cells were transfected with siRNA-LRRC3B plasma (P<0.05). The administration of 50 µg/ml bupivacaine promoted maximum breast cancer cell invasion, and suppressed LRRC3B mRNA expression in cells. However, when LRRC3B was silenced in cancer cells, 20 µg/ml bupivacaine significantly promoted cancer cell invasion, indicating that bupivacaine suppresses the expression of LRRC3B and promotes cell invasion. The present study suggested that LRRC3B serves a protective role in preventing bupivacaine-induced breast cancer recurrence and metastasis.

Identification of 3-substituted-6-(1-(1H-[1,2,3]triazolo[4,5-b]pyrazin-1-yl)ethyl)quinoline derivatives as highly potent and selective mesenchymal-epithelial transition factor (c-Met) inhibitors via metabolite profiling-based structural optimization.

c-Met/HGF signaling pathway plays an important role in cancer progression, and it was considered to be related to poor prognosis and drug resistance. Based on metabolite profiling of (S)-7-fluoro-6-(1-(6-(1-methyl-1H-pyrazol-4-yl)-1H-imidazo[4,5-b]pyrazin-1-yl)ethyl)quinoline (1), a series of 2-substituted or 3-substituted-6-(1-(1H-[1,2,3]triazolo[4,5-b]pyrazin-1-yl)ethyl)quinoline derivatives was rationally designed and evaluated. Most of the 3-substituted derivatives not only exhibited potent activities in both enzymatic and cellular assays, but also were stable in liver microsomes among different species (human, rat and monkey). SAR investigation revealed that introducing of N-methyl-1H-pyrazol-4-yl group at the 3-position of quinoline moiety is beneficial to improve the inhibitory potency, especially in the cellular assays. The influence of fluorine atom at 7-position or 5, 7-position of quinoline moiety and substituents at the 6-position of triazolo[4,5-b]pyrazine core on overall activity is not very significant. Racemate 14, an extremely potent and exquisitely selective c-Met inhibitor, demonstrated favorable pharmacokinetic properties in rats, no significant AO metabolism, and effective tumor growth inhibition in c-Met overexpressed NSCLC (H1993 cell line) and gastric cancer (SNU-5 cell line) xenograft models. Docking analysis indicated that besides the typical interactions of most selective c-Met inhibitors, the intramolecular halogen bond and additional hydrogen bond interactions with kinase are beneficial to the binding. These results may provide deep insight into potential structural modifications for developing potent c-Met inhibitors.