Strengthening and weakening of methane hydrate by water vacancies

Gas clathrate hydrates show promising applications in sustainable technologies such as future energy resources, gas capture and storage. The stability of clathrate hydrates under external load is of great crucial to those important applications, but remains unknown. Water vacancy is a common structural defect in clathrate hydrates. Herein, the mechanical characteristics of sI methane hydrates containing three types of water vacancy are investigated by molecular dynamics simulations with four different water forcefields. Mechanical properties of methane hydrates such as tensile strength are dictated not only by the density but also the type of water vacancy. Surprisingly, the tensile strength of methane hydrates can be weakened or strengthened, depending on the adopted water model and water vacancy density. Strength enhancement mainly results from the formation of new water cages. This work provides critical insights into the mechanics and microstructural properties of methane clathrate hydrates under external load, which is of primary importance in the recovery of natural gas from methane hydrate reservoirs.Cited as: Lin, Y., Liu, Y., Xu, K., Li, T., Zhang, Z., Wu, J. Strengthening and weakening of methane hydrate by water vacancies. Advances in Geo-Energy Research, 2022, 6(1): 23-37. https://doi.org/10.46690/ager.2022.01.0

Fabrication of Crack-free Photonic Crystal Films on Superhydrophobic Nanopin Surface

厦门大学生物仿生及软物质研究院林友辉副教授以及院长刘向阳教授在利用超疏水基底改善胶体小球自组装研究方向取得进展。 目前通过胶体小球自组装方法已构筑了许多复杂却高度有序的光子晶体。但是胶体小球在形成有序结构过程中会不可避免的产生收缩和应力，该方法通常会导致裂纹和缺陷的形成，降低了光子晶体的光学质量，也同时限制了其进一步的应用。 在该研究中，作者基于以上的研究现状，以纳米针状的超疏水表面为基底，来改善胶体小球的自组装，可以减少甚至消除大尺度的裂纹的效果。基于该原理，最后成功制备出厘米级别无裂纹的光子晶体薄膜。【Abstract】sed on their superior optical performance, photonic crystals (PCs) have been investigated as excellent candidates for widespread applications including sensors, displays, separation processes, and catalysis. However, fabrication of large-area PC assemblies with no defects and structurally controllable is still a tough task. Herein, we develop an effective strategy for preparing centimeter-scale crack-free photonic crystals films by the combined effects of soft assembly and superhydrophobic nanopin surfaces. Owing to its large contact angle and low adhesive force on the superhydrophobic substrate, the colloidal suspension exhibits a continuous retraction of the three-phase (gas−liquid−solid) contact line(TCL) in the process of solvent (water molecules) evaporation. The constantly receding TCL can bring the colloidal spheres closer to each other, which could timely close the gaps due to the loss of water molecules. As a result, close-packed and well-ordered assembly structures can be easily obtained. We expect that this work may pave the way to utilize novel superhy drophobic materials for designing and developing high-quality PCs and to apply PCs in different fields.This work is financially supported by National Nature Science Foundation (Nos. 21401154,U1405226), 111 project (B16029), Guangdong Natural Science Foundation (2014A030310005),the Fundamental Research Funds for the Central Universities of China (Nos. 20720170011,20720140528), Ph.D. Programs Foundation of Ministry of Education of China(20130121110018), Fujian Provincial Department of Science & Technology (2014H6022).X.Y.L.'s primary affiliation is the Department of Physics, National University of Singapore

Low-Carbon and economic flexibility scheduling of power system with multiple generation resources penetration

The operation flexibility of the power system suffers great challenges due to the vigorously developing of renewable energy resources under the promotion of the carbon neutralization goal. To this end, this paper proposes an economical and flexible energy scheduling method for power system integrated with multiple generation resources while considering the operation of low-carbon. Specifically, flexibility evaluation indexes are constructed to describe the characteristics of the flexible generation units. Then they are connected with the flexibility of the power system in an economic and low-carbon flexible energy scheduling model. To coordinate the operation economy, flexibility, and carbon emission reduction, the model incorporates demand response, operational characteristics, and flexibility requirements. Further, the model is fully validated through the simulation on the modified IEEE 30-bus system. Results demonstrate that: the proposed method can reduce the system’s carbon emission and total operating costs and promote photovoltaic consumption

上转换荧光点亮软物质体内成像新思路

传统的非侵入性活体生物成像技术主要是基于计算机断层扫描和核磁共振成像等技术，这些技术由于其相对较低的分辨率和对组织的损伤而受到限制。通过从介观尺度将稀土上转换纳米颗粒均匀地组装到丝素蛋白生物支架，使其具备在近红外激发下产生可见光波段发射光的上转换荧光性能。该团队使用低功率连续980 nm波长的近红外激光穿透大鼠皮肤和组织、激发植入的蚕丝丝素生物支架，产生可见光（绿光）图像。揭示了蚕丝生物支架的生物相容性、力学性能和生物降解性，以及组织细胞与生物支架的相互作用。丝素蛋白生物支架是一种软物质，上转换荧光技术为体内软物质成像提供了新思路。【中文摘要】首次采用上转换荧光技术实现了丝素蛋白生物支架体内生物成像，解决了传统体内软物质材料生物成像难以实现实时、高分辨、深穿透和低损伤的局限。【Abstract】In biomedical applications, it is very desirable to monitor the in vivo state of implanted devices, i.e., tracking the location, the state, and the interaction between the implanted devices and cell tissues. To achieve this goal, a generic strategy of soft materials meso-functionalization is presented. This is to acquire silk fibroin (SF) materials with added functions, i.e., in vivo bioimaging/sensing. The functionalization is by 3D materials assembly of functional components, lanthanide(Ln)-doped upconversion nanoparticles (UCNPs) on the mesoscopic scale to acquire upconversion fluorescent emission. To implement the meso-functionalization, the surfaces of UCNPs are modified by the hydroxyl groups (—OH) from SiO2 or polyethylene glycol coating layers, which can interact with the carbonyl groups (C==O) in SF scaffolds. The functionalized silk scaffolds are further implanted subcutaneously into mice, which allows the silk scaffolds to have fluorescent in vivo bioimaging and other biomedical functions. This material functionalization strategy may lead to the rational design of biomaterials in a more generic way.The work was supported by the 111 Project (Grant No. B16029), National Natural Science Foundation of China (Grant Nos. 21404087, 61674050, and U1405226), Fujian Provincial Department of Science and Technology (Grant Nos. 2017J06019, 2014H6022, and 2015J05109), Natural Science Foundation of Guangdong Province (Grant No. 2015A030310007), 1000 Talents Program, and President Foundation from Xiamen University (Grant No. 20720160088), NUS tear 1 funding (WBS: R-144-000-367-112)

ACT001 improved cardiovascular function in septic mice by inhibiting the production of proinflammatory cytokines and the expression of JAK-STAT signaling pathway

Sepsis is a life-threatening multiple organ dysfunction syndrome (MODS) caused by a microbial infection that leads to high morbidity and mortality worldwide. Sepsis-induced cardiomyopathy (SIC) and coagulopathy promote the progression of adverse outcomes in sepsis. Here, we reported that ACT001, a modified compound of parthenolide, improved the survival of sepsis mice. In this work, we used cecal ligation and puncture (CLP) model to induce SIC. Transthoracic echocardiography and HE staining assays were adopted to evaluate the influence of ACT001 on sepsis-induced cardiac dysfunction. Our results showed that ACT001 significantly improved heart function and reduced SIC. Coagulation accelerates organ damage in sepsis. We found that ACT001 decreased blood clotting in the FeCl3-induced carotid artery thrombosis experiment. ACT001 also reduced the production of neutrophil extracellular traps (NETs). RNA-sequencing of heart tissues revealed that ACT001 significantly downregulated the expression of pro-inflammatory cytokines and the JAK-STAT signaling pathway. These results were confirmed with real-time PCR and ELISA. In summary, we found ACT001 rescued mice from septic shock by protecting the cardiovascular system. This was partially mediated by inhibiting pro-inflammatory cytokine production and down-regulating the JAK-STAT signaling

Study of brain network alternations in non-lesional epilepsy patients by BOLD-fMRI

ObjectiveTo investigate the changes of brain network in epilepsy patients without intracranial lesions under resting conditions.MethodsTwenty-six non-lesional epileptic patients and 42 normal controls were enrolled for BOLD-fMRI examination. The differences in brain network topological characteristics and functional network connectivity between the epilepsy group and the healthy controls were compared using graph theory analysis and independent component analysis.ResultsThe area under the curve for local efficiency was significantly lower in the epilepsy patients compared with healthy controls, while there were no differences in global indicators. Patients with epilepsy had higher functional connectivity in 4 connected components than healthy controls (orbital superior frontal gyrus and medial superior frontal gyrus, medial superior frontal gyrus and angular gyrus, superior parietal gyrus and paracentral lobule, lingual gyrus, and thalamus). In addition, functional connectivity was enhanced in the default mode network, frontoparietal network, dorsal attention network, sensorimotor network, and auditory network in the epilepsy group.ConclusionThe topological characteristics and functional connectivity of brain networks are changed in in non-lesional epilepsy patients. Abnormal functional connectivity may suggest reduced brain efficiency in epilepsy patients and also may be a compensatory response to brain function early at earlier stages of the disease