Deep Geophysical Anomalies Beneath the Changbaishan Volcano

Subsurface imaging is key to understanding the origin of intraplate volcanoes. The Changbaishan volcano, located about 2,000 km away from the western Pacific subduction zone, has several debated origins. To investigate this, we compared regional seismic tomography with the electrical resistivity results and obtained high-resolution 1D and quasi-2D velocity-depth profiles. We show that the upper mantle is characterized by two anomalies exhibiting distinct features which cannot be explained by the same mechanism. We document a localized low-velocity anomaly atop the 410-km discontinuity, where the P-wave velocity is reduced more than that of the S-wave (i.e., lower Vp/Vs). We propose that this anomaly is caused by the reduction of the effective moduli during the phase transformation of olivine. The other anomaly, located between 300 and 370 km depth, reveals a significant reduction of the S-wave velocity (i.e., higher Vp/Vs), associated with a reduction of the electrical resistivity, altogether consistent with partial melting

Role of oxidative stress and endoplasmic reticulum stress in drug-induced liver injury

The pathogenesis of drug-induced liver injury (DILI) is still in an early stage of research. However, investigators have shown that both oxidative stress and endoplasmic reticulum (ER) stress play a significant role in the pathological mechanism. However, there is little in-depth literature about these two mechanisms. In order to prevent and improve the clinical symptoms of DILI, it is particularly important to study its pathogenesis. In this review article, the role of ER and oxidative stress in DILI is thoroughly discussed

Hotspots from Top to Bottom

The dynamical and chemical processes of the Earth’s interior are the critical driver of the evolution of various “spheres”, like the hydrosphere, atmosphere, and biosphere, and shape the surface where we live. While the interior of the Earth is largely inaccessible, the surface volcanism provides a unique window into the planet’s physical and chemical evolution. The majority of the volcanism on Earth is generated by decompression melting at the mid- ocean ridges, with a smaller proportion due to dehydration melting at subduction zones, and melting at intraplate volcanoes. Intraplate volcanism away from ridges (like Hawaii) and excessive melting anomalies near or at ridges (like Iceland) are not readily explained by plate tectonics. Such phenomena are also known as hotspots.Hotspots could be fed by active upwellings, or mantle plumes, a distinct scale of flow within mantle convection, separate from the plate-scale flow, and directly linked to the bot- tom thermal boundary layer. In particular, it has long been suggested that hotspots originate from the Large Low Shear Velocity Provinces (LLSVPs) at the core-mantle boundary (CMB), as imaged by seismic waves. However, the presence of mantle plumes under hotspot volcanoes extending to the CMB, and the possible link between LLSVPs and plumes have been the source of debate.In this thesis, I aim to address the link between hotspots and LLSVPs and their relation to the bottom thermal boundary layer by analyzing surface observations and performing analog experiments. By employing a multi-disciplinary approach, this research facilitates a comprehensive exploration from the Earth’s surface to its deep interior. This holistic investigation helps bridge the gap in our understanding of the geophysical and geochemical signals seen at the top thermal boundary layer, and their correlation to the dynamics and entrainment phenomena at the bottom thermal boundary layer.In Chapter 2, I use self-consistent thermodynamic calculations to infer the potential temperature beneath hotspots and mid-ocean ridges in the mantle from seismic tomography. By comparing the excess temperature of hotspots over ridges with buoyancy flux estimates and geochemical signals from hotspots, I have discovered not all hotspots are hot and fed by deep active upwellings; some are cold and require different dynamical mechanisms from those provided by classical plume theory. I have further explored the spatial pattern of global ridge temperature in Chapter 3, and showed the ridge temperature contains fingerprints of past mantle convection and plate tectonics, which can be used to predict the geographic distribution of ridges and disentangle the contribution of deep and shallow processes to temperature and geophysical, geochemical and geological variations observed at ridges.Chapter 2 and 3 serve to provide an observational lens with which I investigate the dynamical, morphological, and chemical relationship between the LLSVPs and plumes with laboratory experiments in later chapters. The working fluid (corn syrup) is heated from below, and cooled from the top, with Earth-like convective vigor. Among different geneses, I focus on two end-members of the LLSVPs: purely thermal plume clusters and an undeformable, fixed pile, or essentially Rayleigh-Benard convection without or with a 3-D-printed obstacle. Utilizing 4-D velocity acquisition 4, Lagrangian analysis 5, and adjoint reconstructions 7, I have quantitatively analyzed the flow in unprecedented detail (Chapters 6 and 8). In the simple Newtonian working fluid we use for our experiments (corn syrup with only has temperature-dependent viscosity, I have identified a diverse array of plume behaviors that could explain a range of observations from neighboring hotspot tracks to the tree-structure of the LLSVPs and seismic velocity local minima in the lowermost mantle (cf. Chapter 6). Plumes do not seem to have site preference in the purely thermal case, while strong and stable plumes tend to rise around and from the rigid LLSVP (cf. Chapter 8). With a thorough material entrainment analysis of the two end-member experiments at different proximity to the LLSVP, the physical locations of reservoirs linked to the geochemical signals seen at hotspots are also inferred using the geographical (dis)correlation of these hotspots and the LLSVPs. This framework leverages the infinite resolution and unaltered physics of real-world experiments, offering a thorough workflow for 4-D viscous flow measurement that could be extended to other terrestrial planets and beyond. My results also open the door to quantitative comparison of laboratory experiments and numerical simulations of geodynamical time-dependent, multi-scale flow

On the relative temperatures of Earth’s volcanic hotspots and mid-ocean ridges

Volcanic hotspots are thought to be fed by hot, active upwellings from the deep mantle, with excess temperatures (Tex) ~100° to 300°C higher than those of mid-ocean ridges. However, Tex estimates are limited in geographical coverage and often inconsistent for individual hotspots. We infer the temperature of oceanic hotspots and ridges simultaneously by converting seismic velocity to temperature. We show that while ~45% of plume-fed hotspots are hot (Tex ≥ 155°C), ~15% are cold (Tex ≤ 36°C) and ~40% are not hot enough to actively upwell (50°C ≤ Tex ≤ 136°C). Hot hotspots have an extremely high helium-3/helium-4 ratio and buoyancy flux, but cold hotspots do not. The latter may originate at upper mantle depths. Alternatively, the deep plumes that feed them may be entrained and cooled by small-scale convection

Glycolysis Aids in Human Lens Epithelial Cells’ Adaptation to Hypoxia

Hypoxic environments are known to trigger pathological damage in multiple cellular subtypes. Interestingly, the lens is a naturally hypoxic tissue, with glycolysis serving as its main source of energy. Hypoxia is essential for maintaining the long-term transparency of the lens in addition to avoiding nuclear cataracts. Herein, we explore the complex mechanisms by which lens epithelial cells adapt to hypoxic conditions while maintaining their normal growth and metabolic activity. Our data show that the glycolysis pathway is significantly upregulated during human lens epithelial (HLE) cells exposure to hypoxia. The inhibition of glycolysis under hypoxic conditions incited endoplasmic reticulum (ER) stress and reactive oxygen species (ROS) production in HLE cells, leading to cellular apoptosis. After ATP was replenished, the damage to the cells was not completely recovered, and ER stress, ROS production, and cell apoptosis still occurred. These results suggest that glycolysis not only performs energy metabolism in the process of HLE cells adapting to hypoxia, but also helps them continuously resist cell apoptosis caused by ER stress and ROS production. Furthermore, our proteomic atlas provides possible rescue mechanisms for cellular damage caused by hypoxia

Laryngeal mask general anaesthesia versus spinal anaesthesia for promoting early recovery of cervical conisation: A randomised, controlled clinical study

Background: Although both spinal and general anaesthesia provides good anaesthesia for cervical conization, spinal anaesthesia delays the return of lower limb movements and urinary function, whereas general anaesthesia requires the patient to be unconscious. It is unclear which anaesthetic technique is more conducive to early postoperative recovery in patients undergoing cervical conization. Patients and methods: 140 patients undergoing cervical conization underwent either laryngeal mask general anaesthesia (LMA, n = 70) or spinal anaesthesia (SA, n = 70). In the LMA group, an i-gel mask was used for airway management. In the SA group, spinal anaesthesia was received with 0.75% ropivacaine (15 mg) in the L3-4 interval. The quality of recovery score (QoR-15) was the primary endpoint of the study. Secondary endpoints included incidence of adverse 24-h analgesia (NRS>3); return of lower limb activity; first bed activity and feeding; and the number of catheters removed at 6, 12 and 24 h postoperatively. Result: The LMA group significantly improved QoR-15 scores (136.62 ± 11.02 vs 119.97 ± 12.75; P 3) within 24 h postoperatively (20% vs 42.8%, P = 0.006); reduced time in bed (15.62 ± 3.83 h vs 18.27 ± 5.57 vs, P = 0.001); improved patient satisfaction (86% vs 27%; P < 0.001); and catheters removal within 24 h (70/70 vs 42/70, P < 0.001). Conclusion: LMA general anaesthesia can facilitate early postoperative recovery in patients undergoing cervical conization compared with conventional spinal anaesthesia. Trial registration: Chinese Clinical Trial Registry (ID: ChiCTR1800019384), http://www.chictr.org.cn/listbycreater.aspx (08/11/2018)

Nutrients and Environmental Factors Cross Wavelet Analysis of River Yi in East China: A Multi-Scale Approach

The accumulation of nutrients in rivers is a major cause of eutrophication, and the change in nutrient content is affected by a variety of factors. Taking the River Yi as an example, this study used wavelet analysis tools to examine the periodic changes in nutrients and environmental factors, as well as the relationship between nutrients and environmental factors. The results revealed that total phosphorus (TP), total nitrogen (TN), and ammonia nitrogen (NH4+&ndash;N) exhibit multiscale oscillation features, with the dominating periods of 16&ndash;17, 26, and 57&ndash;60 months. The continuous wavelet transform revealed periodic fluctuation laws on multiple scales between nutrients and several environmental factors. Wavelet transform coherence (WTC) was performed on nutrients and environmental factors, and the results showed that temperature and dissolved oxygen (DO) have a strong influence on nutrient concentration fluctuation. The WTC revealed a weak correlation between pH and TP. On a longer period, however, pH was positively correlated with TN. The flow was found to be positively correct with N and P, while N and P were found to be negatively correct with DO and electrical conductance (EC) at different scales. In most cases, TP was negatively correlated with 5-day biochemical oxygen demand (BOD5) and permanganate index (CODMn). The correlation between TN and CODMn and BOD5 was limited, and no clear dominant phase emerged. In a nutshell, wavelet analysis revealed that water temperature, pH, DO, flow, EC, CODMn, and BOD5 had a pronounced influence on nutrient concentration in the River Yi at different time scales. In the case of the combination of environmental factors, pH and DO play the largest role in determining nutrient concentration

-30°C cold start optimization of PEMFC based on a data-driven surrogate model and multi-objective optimization algorithm

Cold start is a critical operating scenario for the proton exchange membrane fuel cell (PEMFC), particularly in the field of transportation. Under sub-freezing temperatures, the water inside the cell will freeze and obstruct gas flow paths as well as cover catalyst reaction sites, resulting in a failed startup. This study proposes an optimization method for the -30°C cold start of PEMFC based on a data-driven surrogate model to improve cold start performance and reduce irreversible damage to the cell. A validated PEMFC cold start mechanism model is utilized as the basis for developing an extreme learning machine (ELM) based data-driven surrogate model, which is trained using data collected from the mechanism model and has higher computational efficiency compared with the original model. In addition, the NSGA-II multi-objective optimization algorithm is employed to optimize the current loading strategies and operating parameters using the surrogate model as fitness function. The objectives are to enhance the minimum voltage and reduce startup duration time. Moreover, experimental validation confirms the effectiveness of the proposed method. The test results demonstrate that a cold start from -30°C is achieved within 97 s, with the minimum voltage reaching 0.44 V. Notably, there is a reduction in startup time by 26 s and an increase in the minimum voltage by 0.06 V compared to the base case. This study establishes a foundation for researchers to adjust operating settings during cold start based on diverse applications and requirements

Use of Digital Droplet PCR to Detect Mycobacterium tuberculosis DNA in Whole Blood-Derived DNA Samples from Patients with Pulmonary and Extrapulmonary Tuberculosis

Tuberculosis (TB) is a chronic infectious disease that has been threatening public health for many centuries. The clinical diagnostic procedure for TB is time-consuming and laborious. In the last 20 years, real-time fluorescence-based quantitative PCR (real-time PCR) has become a better alternative for TB diagnosis in clinics due to its sensitivity and specificity. Recently, digital droplet PCR (ddPCR) has been developed, and it might be an ideal alternative to conventional real-time PCR for microorganism detection. In this study, we aimed to assess the capacity of ddPCR and real-time PCR for detecting low levels of circulating Mycobacterium tuberculosis (MTB) DNA. The study involved testing whole blood samples for an MTB DNA target (known as IS6110). Blood samples were obtained from 28 patients with pulmonary TB, 28 patients with extrapulmonary TB, and 28 healthy individuals. The results show that ddPCR could be used to measure low levels of MTB DNA, and it has the potential to be used to diagnose pulmonary and extrapulmonary TB based on clinical samples