Experimental Investigation on the Feasibility and Optimal Frequency of Ultrasonic Assisted Ice Drilling Method

Exploitation of polar resources and scientific research require efficient ice drilling technology. Thermal drilling is a common method for polar ice drilling, and is similar to the principle of ultrasonic assisted drilling; both are drilled by melting ice layers, but improving energy utilization has always been a challenge. In order to improve energy utilization and drilling efficiency, this paper proposes a method for ice drilling with ultrasonic frequency vibration. The mechanism of ultrasonic vibration drilling into ice was analyzed, the solid theoretical foundation for the application of ice melting efficiency under ultrasonic frequency vibration was determined and a series of indoor experiments were conducted. According to experimental data obtained, two conclusions were provided. First, different frequencies have distinct influence on power density, drilling speed and melting rate, and the optimum range excitation frequency for ultrasonic ice drilling is at least 30~32 kHz, under which the ice melting efficiency and drilling speed reached the peak value. Second, ultrasonic assisted drilling was verified to have the ability of improving the efficiency of ice breaking by comparing to thermal drilling under the same power density under 30 kHz. As an environmentally friendly and efficient drilling method, ultrasonic assisted ice drilling has great application prospects in the field of polar exploration. By using Ultrasonic assisted drilling, we demonstrate a strategy for a faster and more efficient drilling method, which is important for humankind

Deformation Law and Spatial Effect of Deep Foundation Pits for Subway Construction in Soil-Rock Composite Strata in Seasonally Frozen Areas

The stability and safety of metro deep foundation pit in the soil-rock composite stratum in the seasonally frozen area are the key issues in the design and construction of the foundation pit. In order to ensure the soil-rock composite stratum in the seasonally frozen area, the deformation of the supporting structure is within the safe range when the deep foundation pit is excavated. At the same time, it will reduce the impact of the construction of metro deep foundation pit on the surrounding buildings. During the construction of foundation pit, close monitoring shall be carried out and the actual monitoring data shall be studied and analyzed. During the excavation of each layer of the foundation pit, monitor the displacement change of the foundation pit support structure and the settlement change of the surrounding ground surface, study the deformation law of the subway deep foundation pit in the soil-rock composite layer, and discuss the spatial effect of the foundation pit excavation in the seasonally frozen area. This paper mainly takes the deep foundation pit project of Anxin Road Station of Changchun Metro Line 5 as the research object, and analyzes the actual monitoring results. The results show that: (1) With the long side of the foundation pit, the deformation of the retaining structure of the foundation pit increases with the distance from the pit corner, and the middle of the long side of the foundation pit is less constrained by the retaining structure. (2) During the excavation of soil-rock composite foundation pit in seasonally frozen soil area, the pile displacement, axial force of support and uplift of support structure caused by rock excavation are relatively small, while the lateral displacement of foundation pit below the rock surface and thawing settlement deformation of soil are basically unchanged. The maximum lateral displacement of the foundation pit at the upper part of the rock surface moves upward. During the construction of deep foundation pit, there is a large displacement before the erection of the third layer of steel support. Attention should be paid to the soil properties of the deep silty clay layer, as well as to the rapid construction and synchronous maintenance

Insights for Oxidative Stress and mTOR Signaling in Myocardial Ischemia/Reperfusion Injury under Diabetes

Diabetes mellitus (DM) displays a high morbidity. The diabetic heart is susceptible to myocardial ischemia/reperfusion (MI/R) injury. Impaired activation of prosurvival pathways, endoplasmic reticulum (ER) stress, increased basal oxidative state, and decreased antioxidant defense and autophagy may render diabetic hearts more vulnerable to MI/R injury. Oxidative stress and mTOR signaling crucially regulate cardiometabolism, affecting MI/R injury under diabetes. Producing reactive oxygen species (ROS) and reactive nitrogen species (RNS), uncoupling nitric oxide synthase (NOS), and disturbing the mitochondrial quality control may be three major mechanisms of oxidative stress. mTOR signaling presents both cardioprotective and cardiotoxic effects on the diabetic heart, which interplays with oxidative stress directly or indirectly. Antihyperglycemic agent metformin and newly found free radicals scavengers, Sirt1 and CTRP9, may serve as promising pharmacological therapeutic targets. In this review, we will focus on the role of oxidative stress and mTOR signaling in the pathophysiology of MI/R injury in diabetes and discuss potential mechanisms and their interactions in an effort to provide some evidence for cardiometabolic targeted therapies for ischemic heart disease (IHD)

Cardiac-derived CTRP9 protects against myocardial ischemia/reperfusion injury via calreticulin-dependent inhibition of apoptosis.

Cardiokines play an essential role in maintaining normal cardiac functions and responding to acute myocardial injury. Studies have demonstrated the heart itself is a significant source of C1q/TNF-related protein 9 (CTRP9). However, the biological role of cardiac-derived CTRP9 remains unclear. We hypothesize cardiac-derived CTRP9 responds to acute myocardial ischemia/reperfusion (MI/R) injury as a cardiokine. We explored the role of cardiac-derived CTRP9 in MI/R injury via genetic manipulation and a CTRP9-knockout (CTRP9-KO) animal model. Inhibition of cardiac CTRP9 exacerbated, whereas its overexpression ameliorated, left ventricular dysfunction and myocardial apoptosis. Endothelial CTRP9 expression was unchanged while cardiomyocyte CTRP9 levels decreased after simulated ischemia/`reperfusion (SI/R) in vitro. Cardiomyocyte CTRP9 overexpression inhibited SI/R-induced apoptosis, an effect abrogated by CTRP9 antibody. Mechanistically, cardiac-derived CTRP9 activated anti-apoptotic signaling pathways and inhibited endoplasmic reticulum (ER) stress-related apoptosis in MI/R injury. Notably, CTRP9 interacted with the ER molecular chaperone calreticulin (CRT) located on the cell surface and in the cytoplasm of cardiomyocytes. The CTRP9-CRT interaction activated the protein kinase A-cAMP response element binding protein (PKA-CREB) signaling pathway, blocked by functional neutralization of the autocrine CTRP9. Inhibition of either CRT or PKA blunted cardiac-derived CTRP9\u27s anti-apoptotic actions against MI/R injury. We further confirmed these findings in CTRP9-KO rats. Together, these results demonstrate that autocrine CTRP9 of cardiomyocyte origin protects against MI/R injury via CRT association, activation of the PKA-CREB pathway, ultimately inhibiting cardiomyocyte apoptosis

Prediction method of shield tunneling parameters in pebble stratum formed by weathered granite and quartzite

The pebble formation formed by weathered quartzite and granite is usually of high strength, strong permeability and poor self stability, which brings great difficulties to shield tunneling. It is necessary to adjust the tunneling parameters at any time to prevent the consequences of instability of the tunnel face, loss of stratum and surface settlement caused by the imbalance of the soil bin pressure. GA algorithm is embedded into PSO algorithm for parameter optimization, and grey theory is combined to establish the prediction model of soil chamber pressure based on grey least square support vector machine, which can solve the problem of difficult control of tunneling parameters in pebble stratum formed by weathered quartzite and granite. Research indicates: GA-PSO-GLSSVM chamber Earth pressure prediction model enhances the EPB chamber Earth pressure forecast accuracy in complicated strata by integrating the global search capability of the GA algorithm, the quick convergence of the PSO algorithm, and the anti-disturbance capability of the GM model. The GA-PSO-GLSSVM model has high goodness-of-fit and accuracy compared with other prediction models. This model can successfully prevent the a series of undesirable consequences such as destabilization of the palm surface, missing strata and settlement due to ground surface due to pressure imbalance in the soil chamber pressure. The research results can provide reference for EPB shield tunneling parameter control in Grade V surrounding rock

Measuring charge distribution of molecular cations by atomic Coulomb probe microscope

Imaging the charge distributions and structures of molecules and clusters will promote the understanding of the dynamics of the quantum system. Here, we report a method by using an Ar atom as a tip to probe the charge distributions of benzene (Bz) cations in gas phase. Remarkably, the measured charge distributions of Bz cation (QH =0.204,QC=-0.037)and dication (QH =0.248,QC=0.0853)agree well with the calculated Mulliken distributions,and the structures of Bz dimer is reconstructed by using the measured charge distributions. The structures of two Bz dimer isomers (T-shaped and PD isomers) can be resolved from the measured inter-molecular potential V(R) between two Bz ions, and the structures of Bz dimer agree well with the theoretical predictions.Comment: 7 pages, 3 Figure

ASFV infection induces macrophage necroptosis and releases proinflammatory cytokine by ZBP1-RIPK3-MLKL necrosome activation

African swine fever (ASF) is an infectious disease characterized by hemorrhagic fever, which is highly pathogenic and causes severe mortality in domestic pigs. It is caused by the African swine fever virus (ASFV). ASFV is a large DNA virus and primarily infects porcine monocyte macrophages. The interaction between ASFV and host macrophages is the major reason for gross pathological lesions caused by ASFV. Necroptosis is an inflammatory programmed cell death and plays an important immune role during virus infection. However, whether and how ASFV induces macrophage necroptosis and the effect of necroptosis signaling on host immunity and ASFV infection remains unknown. This study uncovered that ASFV infection activates the necroptosis signaling in vivo and macrophage necroptosis in vitro. Further evidence showed that ASFV infection upregulates the expression of ZBP1 and RIPK3 to consist of the ZBP1-RIPK3-MLKL necrosome and further activates macrophage necroptosis. Subsequently, multiple Z-DNA sequences were predicted to be present in the ASFV genome. The Z-DNA signals were further confirmed to be present and colocalized with ZBP1 in the cytoplasm and nucleus of ASFV-infected cells. Moreover, ZBP1-mediated macrophage necroptosis provoked the extracellular release of proinflammatory cytokines, including TNF-α and IL-1β induced by ASFV infection. Finally, we demonstrated that ZBP1-mediated necroptosis signaling inhibits ASFV replication in host macrophages. Our findings uncovered a novel mechanism by which ASFV induces macrophage necroptosis by facilitating Z-DNA accumulation and ZBP1 necrosome assembly, providing significant insights into the pathogenesis of ASFV infection

Inclusive and accurate clinical diagnostics using intelligent computation and smartphone imaging

Smartphone-based colorimetry has been widely applied in clinical analysis, although significant challenges remain in its practical implementation, including the need to consider biases introduced by the ambient imaging environment, which limit its potential within a clinical decision pathway. In addition, most commercial devices demonstrate variability introduced by manufacturer-to-manufacturer differences. Here, we undertake a systematic characterization of the potential imaging interferences that lead to this limited performance in conventional smartphones and, in doing so, provide a comprehensive new understanding of smartphone color imaging. Through derivation of a strongly correlated parameter for sample quantification, we enable real-time imaging, which for the first time, takes the first steps to turning the mobile phone camera into an analytical instrument – irrespective of model, software, and the operating systems used. We demonstrate clinical applicability through the imaging of patients’ skin, enabling rapid and convenient diagnosis of cyanosis and measurement of local oxygen concentration to a level that unlocks clinical decision-making for monitoring cardiovascular disease and anemia. Importantly, we show that our solution also accounts for the differences in individuals’ skin tones as measured across the Fitzpatrick scale, overcoming potential clinically significant errors in current optical oximetry