Controlled shaped-charge blasting technology for deep underground tunnel engineering

S brzim razvojem gospodarstva i društva značajno je porasla potražnja za mineralnim sirovinama i energijom. Međutim, teško je poboljšati učinkovitost miniranja i kontrolirati stabilnost okolnih stijena tijekom izrade konstrukcija u dubokom podzemlju. U ovom je radu kao tehnička osnova upotrijebljen duboki podzemni tunel reverzibilne hidroelektrane Tianchi u Kini. Na temelju stanja preraspodjele naprezanja okolnih stijena nakon iskopa miniranjem, teorijskim analizama, numeričkim simulacijama i in situ ispitivanjima istraženi su učinci širenja pukotina i dinamički odziv okolne stijene na temelju različitih metoda miniranja. Provedena je analiza mehanizma usmjerenoga stvaranja pukotina s obzirom na utjecaj razmaka bušotina i in situ naprezanja. Pokazalo se da početno naprezanje tla potiče širenje pukotina pri miniranju u konturnoj bušotini nastaloj glatkim miniranjem u smjeru pravca minske bušotine. Rezultati testiranja pokazali su da je primjenom kontroliranih metoda miniranja kumulativnim nabojem podzemnih tunela moguće povećati stopu iskorištenosti eksploziva, smanjiti vibracije pri miniranju i postići značajan učinak na usmjereno formiranje pukotina. Rezultati istraživanja od velike su važnosti za građevinarstvo jer mogu dovesti do poboljšanja tehnologije miniranja, učinka stvaranja kontura miniranjem i kontrole stabilnosti okolne stijene.With the rapid development of the economy and society, the demand for mineral resources and energy has increased rapidly. However, it is difficult to improve the efficiency of blasting construction and control the stability of the surrounding rock in deep underground engineering. In this study, the deep underground tunnel of the Tianchi pumped-storage hydropower station in China was considered as the engineering background. Based on the stress redistribution state of the surrounding rock after blasting excavation, the crack propagation effect and dynamic response of the surrounding rock under different controlled blasting methods were studied through theoretical analyses, numerical simulations and in situ tests. The mechanism of directional crack formation was analysed by considering the influence of hole spacing and in situ stress. It was shown that the initial ground stress was conducive to the propagation of the blasting crack in the contour hole of smooth blasting towards the direction line of the blast hole. The test results showed that using controlled shaped-charge blasting methods in the blasting excavation of underground tunnels can improve the utilisation rate of explosives, reduce blasting vibration and achieve a significant effect on directional crack formation. The research results have important engineering significance as they can lead to improvements in the blasting technique, a contour-forming effect of the blasting excavation and control of the stability of the surrounding rock

Depression Involved in the Chemotherapy Induced Event-based Prospective Memory Impairment in Breast Cancer Survivors

The aim of this study was to investigate the relationships between depression and occurrence of chemotherapy induced prospective memory impairment in patients with breast cancer (BC).The 63 BC patients before and after chemotherapy were administered with the self-rating depression scale (SDS) and a battery of cognitive neuropsychological tests including event-based and time-based prospective memory (EBPM and TBPM, respectively) tasks. The changes in their prospective memory and cognitive neuropsychological characteristics before and after chemotherapy were compared. Compared with the scores before chemotherapy, the EBPM score exhibited a statistically significant difference after chemotherapy (t = 6.069, P 0.05). Further, compared with the patients without depression, the patients with depression exhibited a statistically significant difference in the EBPM score (t = -4.348, P 0.05). Post-chemotherapy, EBPM and overall cognitive functions in BC patients merged with depression were found to decline, while TBPM did not show a significant change, suggesting that the combination of chemotherapy and depression might be related with the occurrence of post-chemotherapy EBPM impairment

4β-Hy­droxy-12,13-ep­oxy­trichothec-9-ene

The asymmetric unit in the crystal of the title compound, C15H22O3, contains two independent mol­ecules with similar structures. Each mol­ecule contains two six-membered rings and one five-membered ring. The five-membered ring displays an envelope conformation with the C atom linking the epoxy group as the flap, while the two six-membered rings show half-chair conformations. The two independent mol­ecules are linked by an O—H⋯O hydrogen bond. These dimers are further linked by O—H⋯O hydrogen bonds, forming supra­molecular chains running along the a axis

Loaded delta-hemolysin shapes the properties of Staphylococcus aureus membrane vesicles

BackgroundMembrane vesicles (MVs) are nanoscale vesicular structures produced by bacteria during their growth in vitro and in vivo. Some bacterial components can be loaded in bacterial MVs, but the roles of the loaded MV molecules are unclear.MethodsMVs of Staphylococcus aureus RN4220 and its derivatives were prepared. Dynamic light scattering analysis was used to evaluate the size distribution, and 4D-label-free liquid chromatography–tandem mass spectrometry analysis was performed to detect protein composition in the MVs. The site-mutation S. aureus RN4220-Δhld and agrA deletion mutant RN4220-ΔagrA were generated via allelic replacement strategies. A hemolysis assay was performed with rabbit red blood cells. CCK-8 and lactate dehydrogenase release assays were used to determine the cytotoxicity of S. aureus MVs against RAW264.7 macrophages. The serum levels of inflammatory factors such as IL-6, IL-1β, and TNFα in mice treated with S. aureus MVs were detected with an enzyme-linked immunosorbent assay kit.ResultsDelta-hemolysin (Hld) was identified as a major loaded factor in S. aureus MVs. Further study showed that Hld could promote the production of staphylococcal MVs with smaller sizes. Loaded Hld affected the diversity of loaded proteins in MVs of S. aureus RN4220. Hld resulted in decreased protein diversity in MVs of S. aureus. Site-mutation (RN4220-Δhld) and agrA deletion (RN4220-ΔagrA) mutants produced MVs (ΔhldMVs and ΔagrAMVs) with a greater number of bacterial proteins than those derived from wild-type RN4220 (wtMVs). Moreover, Hld contributed to the hemolytic activity of wtMVs. Hld-loaded wtMVs were cytotoxic to macrophage RAW264.7 cells and could stimulate the production of inflammatory factor IL-6 in vivo.ConclusionThis study presented that Hld was a major loaded factor in S. aureus MVs, and the loaded Hld played vital roles in the MV-property modification