Balancing the Binding of Intermediates Enhances Alkaline Hydrogen Oxidation on D-Band Center Modulated Pd Sites.

Exploring efficient alkaline hydrogen oxidation reaction (HOR) electrocatalysts is of great concern for constructing anion exchange membrane fuel cells (AEMFCs). Herein, d-band center modulated PdCo alloys with ultralow Pd content anchored onto the defective carbon support (abbreviated as PdCo/NC hereafter) are proposed as highly efficient HOR catalyst. The as-prepared catalyst exhibits exceptional HOR performance compared to the Pt/C catalyst, achieving thermodynamically spontaneous and kinetically preferential reactions. Specifically, the resultant PdCo/NC demonstrates a marked enhancement in alkaline HOR performance, with the highest mass and specific activities of 1919.6 mA mgPd-1 and 1.9 mA cm-2, 51.1 and 4.2 times higher than those of benchmark of Pt/C, along with an excellent stability in a chronoamperometry test. In the analysis of in situ Raman spectra, it was discovered that tetrahedrally coordinated H-bonded water molecules were formed during the HOR process. This indicates that the promotion of interfacial water molecule formation and enhancement of HOR activities in PdCo/NC are facilitated by defect engineering and the turning of d-band center in PdCo alloy. The essential knowledge obtained in this study could open up a new direction for modifying the electronic structure of cost-effective HOR catalysts through electronic structure engineering.

Predicting balloon shape in percutaneous microcompression : an observational comparative analysis of Meckel's cave imaging and balloon morphology.

Achieving a pear-shaped balloon holds pivotal significance in the context of successful percutaneous microcompression procedures for trigeminal neuralgia. However, inflated balloons may assume various configurations, whether it is inserted into Meckel's cave or not. The absence of an objective evaluation metric has become apparent. To investigate the relationship between the morphology of Meckel's Cave and the balloon used in percutaneous microcompression for trigeminal neuralgia and establish objective criteria for assessing balloon shape in percutaneous microcompression procedures. This retrospective study included 58 consecutive patients with primary trigeminal neuralgia. Data included demographic, clinical outcomes, and morphological features of Meckel's cave and the balloon obtained from MRI and Dyna-CT imaging. MRI of Meckel's cave and Dyna-CT of intraoperative balloon were modeled, and the morphological characteristics and correlation were analyzed. The reconstructed balloon presented a fuller morphology expanding outward and upward on the basis of Meckel's cave. The projected area of balloon was strongly positively correlated with the projected area of Meckel's cave. The Pearson correlation coefficients were 0.812 (P<0.001) for axial view, 0.898 (P<0.001) for sagittal view and 0.813 (P<0.001) for coronal view. Similarity analysis showed that the sagittal projection image of Meckel's cave and that of the balloon had good similarity. This study reveals that the balloon in percutaneous microcompression essentially represents an expanded morphology of Meckel's cave, extending outward and upward. There is a strong positive correlation between the volume and projected area of the balloon and that of Meckel's cave. Notably, the sagittal projection image of Meckel's cave serves as a reliable predictor of the intraoperative balloon shape. This method has a certain generalizability and can help providing objective criteria for judging balloon shape during percutaneous microcompression procedures.

Hepatic IRE1α-XBP1 signaling promotes GDF15-mediated anorexia and body weight loss in chemotherapy.

Platinum-based chemotherapy drugs can lead to the development of anorexia, a detrimental effect on the overall health of cancer patients. However, managing chemotherapy-induced anorexia and subsequent weight loss remains challenging due to limited effective therapeutic strategies. Growth differentiation factor 15 (GDF15) has recently gained significant attention in the context of chemotherapy-induced anorexia. Here, we report that hepatic GDF15 plays a crucial role in regulating body weight in response to chemo drugs cisplatin and doxorubicin. Cisplatin and doxorubicin treatments induce hepatic Gdf15 expression and elevate circulating GDF15 levels, leading to hunger suppression and subsequent weight loss. Mechanistically, selective activation by chemotherapy of hepatic IRE1α-XBP1 pathway of the unfolded protein response (UPR) upregulates Gdf15 expression. Genetic and pharmacological inactivation of IRE1α is sufficient to ameliorate chemotherapy-induced anorexia and body weight loss. These results identify hepatic IRE1α as a molecular driver of GDF15-mediated anorexia and suggest that blocking IRE1α RNase activity offers a therapeutic strategy to alleviate the adverse anorexia effects in chemotherapy.

Optimizing Intermediate Adsorption over PdM (M=Fe, Co, Ni, Cu) Bimetallene for Boosted Nitrate Electroreduction to Ammonia.

Electrochemical reduction of nitrate to ammonia (NO3RR) is a promising and eco-friendly strategy for ammonia production. However, the sluggish kinetics of the eight-electron transfer process and poor mechanistic understanding strongly impedes its application. To unveil the internal laws, herein, a library of Pd-based bimetallene with various transition metal dopants (PdM (M=Fe, Co, Ni, Cu)) are screened to learn their structure-activity relationship towards NO3RR. The ultra-thin structure of metallene greatly facilitates the exposure of active sites, and the transition metals dopants break the electronic balance and upshift its d-band center, thus optimizing intermediates adsorption. The anisotropic electronic characteristics of these transition metals make the NO3RR activity in the order of PdCu>PdCo≈PdFe>PdNi>Pd, and a record-high NH3 yield rate of 295 mg h-1 mgcat -1 along with Faradaic efficiency of 90.9 % is achieved in neutral electrolyte on PdCu bimetallene. Detailed studies further reveal that the moderate N-species (*NO3 and *NO2) adsorption ability, enhanced *NO activation, and reduced HER activity facilitate the NH3 production. We believe our results will give a systematic guidance to the future design of NO3RR catalysts.

Identification of miR-20b-5p as an inhibitory regulator in cardiac differentiation via TET2 and DNA hydroxymethylation.

BACKGROUND: Congenital heart disease (CHD) is a prevalent congenital cardiac malformation, which lacks effective early biological diagnosis and intervention. MicroRNAs, as epigenetic regulators of cardiac development, provide potential biomarkers for the diagnosis and treatment of CHD. However, the mechanisms underlying miRNAs-mediated regulation of cardiac development and CHD malformation remain to be further elucidated. This study aimed to explore the function of microRNA-20b-5p (miR-20b-5p) in cardiac development and CHD pathogenesis. METHODS AND RESULTS: miRNA expression profiling identified that miR-20b-5p was significantly downregulated during a 12-day cardiac differentiation of human embryonic stem cells (hESCs), whereas it was markedly upregulated in plasma samples of atrial septal defect (ASD) patients. Our results further revealed that miR-20b-5p suppressed hESCs-derived cardiac differentiation by targeting tet methylcytosine dioxygenase 2 (TET2) and 5-hydroxymethylcytosine, leading to a reduction in key cardiac transcription factors including GATA4, NKX2.5, TBX5, MYH6 and cTnT. Additionally, knockdown of TET2 significantly inhibited cardiac differentiation, which could be partially restored by miR-20b-5p inhibition. CONCLUSIONS: Collectively, this study provides compelling evidence that miR-20b-5p functions as an inhibitory regulator in hESCs-derived cardiac differentiation by targeting TET2, highlighting its potential as a biomarker for ASD.

Tuning the Interface Stability of Nickel-Rich NCM Cathode Against Aggressive Structural Collapse via the Synergistic Effect of Additives.

Nickel-rich layered oxides are envisaged as one of the most promising alternative cathode materials for lithium-ion batteries, considering their capabilities to achieve ultrahigh energy density at an affordable cost. Nonetheless, with increasing Ni content in the cathodes comes a severe extent of Ni4+ redox side reactions on the interface, leading to fast capacity decay and structural stability fading over extended cycles. Herein, dual additives of bis(vinylsulfonyl)methane (BVM) and lithium difluorophosphate (LiDFP) are adopted to synergistically generate the F-, P-, and S-rich passivation layer on the cathode, and the Ni4+ activity and dissolution at high voltage are restricted. The sulfur-rich layer formed by the polymerization of BVM, combined with the Li3PO4 and LiF phases derived from LiDFP, alleviates the problems of increased impedance, cracks, and an irreversible H2-H3 phase transition. Consequently, the Ni-rich LiNixM1-xO2 (x > 0.95) button half-cell cycled in LiDFP + BVM electrolyte exhibits a significant discharging capacity of 181.4 mAh g-1 at 1 C (1 C = 200 mA g-1) with retention of 83.7% after 100 cycles, surpassing the performance of the commercial electrolyte (160.7 mAh g-1) with retention of 53.3%. Remarkably, the NCM95||graphite pouch cell exhibits a remarkable capacity retention of 95.5% after 200 cycles. This work inspires the rational design of electrolyte additives for ultrahigh-energy batteries with nickel-rich layered oxide cathodes.

A flavonoid metabolon: cytochrome b5 enhances B-ring trihydroxylated flavan-3-ols synthesis in tea plants.

Flavan-3-ols are prominent phenolic compounds found abundantly in the young leaves of tea plants. The enzymes involved in flavan-3-ol biosynthesis in tea plants have been extensively investigated. However, the localization and associations of these numerous functional enzymes within cells have been largely neglected. In this study, we aimed to investigate the synthesis of flavan-3-ols in tea plants, particularly focusing on epigallocatechin gallate. Our analysis involving the DESI-MSI method to reveal a distinct distribution pattern of B-ring trihydroxylated flavonoids, primarily concentrated in the outer layer of buds. Subcellular localization showed that CsC4H, CsF3'H, and CsF3'5'H localizes endoplasmic reticulum. Protein-protein interaction studies demonstrated direct associations between CsC4H, CsF3'H, and cytoplasmic enzymes (CHS, CHI, F3H, DFR, FLS, and ANR), highlighting their interactions within the biosynthetic pathway. Notably, CsF3'5'H, the enzyme for B-ring trihydroxylation, did not directly interact with other enzymes. We identified cytochrome b5 isoform C serving as an essential redox partner, ensuring the proper functioning of CsF3'5'H. Our findings suggest the existence of distinct modules governing the synthesis of different B-ring hydroxylation compounds. This study provides valuable insights into the mechanisms underlying flavonoid diversity and efficient synthesis and enhances our understanding of the substantial accumulation of B-ring trihydroxylated flavan-3-ols in tea plants.

Principles and Design of Biphasic Self-Stratifying Batteries Toward Next-Generation Energy Storage.

Large-scale energy storage devices play pivotal roles in effectively harvesting and utilizing green renewable energies (such as solar and wind energy) with capricious nature. Biphasic self-stratifying batteries (BSBs) have emerged as a promising alternative for grid energy storage owing to their membraneless architecture and innovative battery design philosophy, which holds promise for enhancing the overall performance of the energy storage system and reducing operation and maintenance costs. This minireview aims to provide a timely review of such emerging energy storage technology, including its fundamental design principles, existing categories, and prototype architectures. The challenges and opportunities of this undergoing research topic will also be systematically highlighted and discussed to provide guidance for the subsequent R&D of superior BSBs while conducive to bridging the gap for their future practical application.

Evolution of Grain Boundaries Promoted Hydrogen Production for Industrial-Grade Current Density.

The development of efficient and durable high-current-density hydrogen production electrocatalysts is crucial for the large-scale production of green hydrogen and the early realization of hydrogen economic blueprint. Herein, the evolution of grain boundaries through Cu-mediated NiMo bimetallic oxides (MCu-BNiMo), which leading to the high efficiency of electrocatalyst for hydrogen evolution process (HER) in industrial-grade current density, is successfully driven. The optimal MCu0.10-BNiMo demonstrates ultrahigh current density (>2 A cm-2) at a smaller overpotential in 1 m KOH (572 mV), than that of BNiMo, which does not have lattice strain. Experimental and theoretical calculations reveal that MCu0.10-BNiMo with optimal lattice strain generated more electrophilic Mo sites with partial oxidation owing to accelerated charge transfer from Cu to Mo, which lowers the energy barriers for H* adsorption. These synergistic effects lead to the enhanced HER performance of MCu0.10-BNiMo. More importantly, industrial application of MCu0.10-BNiMo operated in alkaline electrolytic cell is also determined, with its current density reached 0.5 A cm-2 at 2.12 V and 0.1 A cm-2 at 1.79 V, which is nearly five-fold that of the state-of-the-art HER electrocatalyst Pt/C. The strategy provides valuable insights for achieving industrial-scale hydrogen production through a highly efficient HER electrocatalyst.

Dilemma of Low-Cost Filter Paper as Separator: Toughen Its Wet Strength for Robust Aqueous Zinc-Ion Batteries.

The industrialization of aqueous zinc-ion batteries (AZIBs) is hampered by poor-performance separators. Filter paper (FP), with mature production processes and low prices, has potential as a separator. However, its swelling and decline of mechanical durability in aqueous environments make it easily punctured by dendrites. In response, wet strength promotion is proposed to toughen FP for robust AZIBs, termed wet-strengthened FP (WSFP). Due to the self-cross-linking network formed on cellulose fibers, water molecules are prevented from easily permeating and disrupting the hydrogen bonds between cellulose molecules. Moreover, the positively charged network can anchor SO42-, thus increasing the Zn2+ transference number and facilitating uniform zinc deposition. Surprisingly, the half and full cells with the WSFP separator present much more stable cycling than untreated FP and glass fiber (GF) separators. These results suggest that robust and low-cost WSFP separators provide a new avenue for the development of high-performance AZIBs with potential for commercialization.

Molecular Coupling Strategy Achieving In Situ Synthesis of Agglomeration-Free Solid Composite Electrolytes.

Solid composite electrolytes (SCEs) synergize inorganic and polymer merits for viable commercial application. However, inferior filler-polymer interfacial stability ultimately leads to the agglomeration of inorganic particles and greatly impedes Li+ migration. Herein, triethoxyvinylsilane (VTEO) is employed to form a strong chemical interaction between poly(vinylene carbonate) (PVC) and montmorillonite (MMT) via in situ solidification, which eliminates the agglomeration and improves interfacial compatibility. Consequently, the obtained solid composite electrolytes (PVC-s-MMT) achieve increased Li+ conductivity (0.4 mS cm-1 at 25 °C), enhanced transference number (0.74), and increased oxidation potential (5.2 V). The Li/PVC-s-MMT/LiFePO4 cells exhibit outstanding cycling performance (>99.5% after 600 cycles) at 1C at room temperature. Moreover, density functional theory (DFT) calculations are applied to uncover the fast interfacial conducting channels of PVC-s-MMT. Our work provides a feasible in situ synthesis method to prepare agglomeration-free SCEs, which is highly compatible with existing battery production processes of liquid electrolytes.

Efficacy and safety of percutaneous balloon compression for bilateral trigeminal neuralgia: a retrospective study.

BACKGROUND: Percutaneous balloon compression (PBC) of the Gasserian ganglion is steadily gaining traction within the trigeminal neuralgia (TN) community. Bilateral trigeminal neuralgia (BTN) is a rare condition, and its treatment remains challenging. As far as we know, there are currently no research reports on the treatment outcomes of PBC for BTN.The purpose of this study is to meticulously evaluate the efficacy and safety of PBC for BTN in our medical institution. METHODS: In this retrospective study, we collected and analyzed the medical records of all patients with BTN who underwent the PBC procedure at the Department of Neurosurgery at Hebei General Hospital from July 2017 to July 2023. After undergoing PBC therapy, all patients were promptly assessed for treatment efficacy based on the modified Barrow Neurological Institute (BNI) pain intensity grading scale. RESULTS: All 37 patients with BTN experienced significant pain relief (BNI I-IIIb) immediately following unilateral PBC treatment. Among these patients, 25 reported relief from pain on the non-operative side, which was effectively managed with medication. Out of the 12 patients who did not experience improvement in contralateral symptoms, 11 received contralateral PBC. Out of the 48 treated sides, 47 sides (97.9%) achieved excellent pain control following a single PBC procedure. The follow-up times ranged from 2 to 62 months. At the 1-year follow-up, 94.6% of the patients maintained excellent therapeutic outcomes.Three recurrent patients underwent repeated unilateral PBC, and all of them maintained excellent pain control postoperatively. At the last follow-up, satisfaction was at 91.7% (measured using the Likert scale), with no severe complications occurring. CONCLUSIONS: The results indicate that PBC is an effective and relatively safe method for treating BTN, offering a valuable option for pain control in these rare cases of TN.

Manipulation of Electronic States of Pt Sites via d-Band Center Tuning for Enhanced Oxygen Reduction Reaction in Proton Exchange Membrane Fuel Cells.

Expediting the torpid kinetics of the oxygen reduction reaction (ORR) at the cathode with minimal amounts of Pt under acidic conditions plays a significant role in the development of proton exchange membrane fuel cells (PEMFCs). Herein, a novel Pt-N-C system consisting of Pt single atoms and nanoparticles anchored onto the defective carbon nanofibers is proposed as a highly active ORR catalyst (denoted as Pt-N-C). Detailed characterizations together with theoretical simulations illustrate that the strong coupling effect between different Pt sites can enrich the electron density of Pt sites, modify the d-band electronic environments, and optimize the oxygen intermediate adsorption energies, ultimately leading to significantly enhanced ORR performance. Specifically, the as-designed Pt-N-C demonstrates exceptional ORR properties with a high half-wave potential of 0.84 V. Moreover, the mass activity of Pt-N-C reaches 193.8 mA gPt-1 at 0.9 V versus RHE, which is 8-fold greater than that of Pt/C, highlighting the enormously improved electrochemical properties. More impressively, when integrated into a membrane electrode assembly as cathode in an air-fed PEMFC, Pt-N-C achieved a higher maximum power density (655.1 mW cm-2) as compared to Pt/C-based batteries (376.25 mW cm-2), hinting at the practical application of Pt-N-C in PEMFCs.

Extending Ring-Chain Coupling Empirical Law to Lithium-Mediated Electrochemical Ammonia Synthesis.

With its efficient nitrogen fixation kinetics, electrochemical lithium-mediated nitrogen reduction reaction (LMNRR) holds promise for replacing Haber-Bosch process and realizing sustainable and green ammonia production. However, the general interface problem in lithium electrochemistry seriously impedes the further enhancement of LMNRR performance. Inspired by the development history of lithium battery electrolytes, here, we extend the ring-chain solvents coupling law to LMNRR system to rationally optimize the interface during the reaction process, achieving nearly a two-fold Faradaic efficiency up to 54.78±1.60 %. Systematic theoretical simulations and experimental analysis jointly decipher that the anion-rich Li+ solvation structure derived from ring tetrahydrofuran coupling with chain ether successfully suppresses the excessive passivation of electrolyte decomposition at the reaction interface, thus promoting the mass transfer of active species and enhancing the nitrogen fixation kinetics. This work offers a progressive insight into the electrolyte design of LMNRR system.

Strong Replaces Weak: Design of H-Bond Interactions Enables Cryogenic Aqueous Zn Metal Batteries.

Despite the numerous advantages of aqueous Zn batteries, their practical application under cryogenic conditions is hindered by the freezing of the electrolyte because the abundance of hydrogen bonds (H-bonds) between H2O molecules drives the aqueous system to transform to an orderly frozen structure. Here, a design of H-bond interactions based on the guiding ideology of "strong replaces weak" is proposed. The strong H-bonds formed between introduced eutectic components and water molecules break down the weak H-bonds in the original water molecule network, which contributes to an ultralow freezing point and a high ionic conductivity of 1.7 mS cm-1 at -40 °C. Based on multiperspective theoretical simulations and tailor-made in situ cooling Raman characterizations, it has been demonstrated that substituting weak H-bonds with strong H-bonds facilitates the structural reshaping of Zn2+ solvation and remodeling of the H-bond network in the electrolyte. Endowed with this advantage, reversible and stable Zn plating/stripping behaviors could be realized at -40 °C, and the full cells display a high discharge capacity (200 mA h g-1) at -40 °C with ∼75% capacity retention after 1000 cycles. This study will expand the design philosophy of antifreezing aqueous electrolytes and provide a perspective to promote the adoption of Zn metal batteries for cryogenic environment large-scale energy storage.

Leveling the Zn Anode by Crystallographic Orientation Manipulation.

Dendrite growth and corrosion of Zn metal anodes result in the limited reversibility of aqueous Zn metal batteries (ZMBs), hindering their prospects as large-scale energy storage devices. Inspired by the similarity of conventional electroplating industrial engineering and Zn deposition in ZMBs, we tend to utilize a low-cost leveling agent (LEA), 1,4-butynediol, to level the Zn deposition. Combining theoretical with in situ experimental characterizations, the preferential adsorption of LEA molecules on different lattice planes can contribute to crystallographic orientation manipulation of the (002) plane, causing good inhibition of dendrite growth. Additionally, the adsorption of LEA molecules on the Zn surface can also prevent undesirable corrosion. Endowed with these merits, symmetric cells and full cells with the LEA additive achieve improved stability and reversibility. This work provides new inspiration for introducing traditional electroplating additives into high-performance ZMBs and gives researchers a direction for choosing electrolyte additives, which also has potential to be applied to other metal anodes.

Trapping High-Activity Water in Nature-Inspired Plant-Derived Separator to Realize Ultrastable Interfacial Chemistry of Zn Anode.

Side reactions caused by highly active water molecules, including severe corrosion, hydrogen evolution, and dendrite growth, are impediments to the advancement of aqueous zinc ion batteries (ZIBs). Here, inspired by the pivotal role of plant fibers to prevent dehydration in nature, we designed a unique water-retaining plant fiber (WRPF) separator with strong hygroscopic ability to adsorb and trap water molecules. Elaborated theoretical and experimental characterizations prove that high-activity water could be sequestered by a WRPF separator, alleviating water-induced side reactions and accelerating the desolvation of hydrate Zn2+. Prominently, reversible Zn plating and stripping could be realized in Zn//Cu batteries. Even with elevated cathodic mass loading (21.94 mg cm-2), the Zn//VS2 full cell delivers high areal capacity 3.3 mAh cm-2 and well-maintained stability. The present study offers a versatile design strategy for separators using nature-inspired materials, aiming to address the challenging issue of "water" and achieve ultrastable interfacial chemistry of Zn anode.

2 A cm-2 Level Large-Scale Production of Hydrogen Enabled by Constructing Higher Capacity of Interface "Electron Pocket".

The batch production of high-purity hydrogen is a key problem that restricts the progress of fuel cells and the blueprint for achieving carbon neutrality. Transition-metal chalcogenide heterojunctions exhibit certain activity toward electrochemical overall water splitting (EOWS), but their high-current-density catalytic performances are still unsatisfactory due to the slow kinetic progression (H* or *O → *OOH). Inspired by the "electron pocket" theory, we designed a Ni-Mo bimetallic disulfide interface heterojunction electrocatalyst system (NM-IHJ-V) with high electronic storage capacity around the Fermi level (-0.5 eV, +0.5 eV) (e-DFE), which injects more power into the kinetic progression processes of intermediate species in the EOWS process. Consequently, it achieves a superhigh current density of 2 A cm-2 level for EOWS (only 1.98 V voltage is needed), which is 11.23-fold higher than that of the benchmarked Pt/C//IrO2 (178 mA cm-2@1.98 V), as well as an excellent long-term stability of 200 h. Most strikingly, NM-IHJ-V can efficiently produce hydrogen at currents up to 5 A. Our proposed strategy of constructing catalysts to produce hydrogen at superhigh current density through the electron pocket theory will supply valuable insights for the designing other catalytic systems.

Diagnostic Value of Blink Reflex Combined with Trigeminal Somatosensory Evoked Potential in Trigeminal Neuralgia.

Objective: To explore the diagnostic value of blink reflex combined with trigeminal somatosensory evoked potential (TSEP) in trigeminal neuralgia. Methods: A total of 147 patients with trigeminal neuralgia were enrolled as the research objects between February 2022 and February 2023. After admission, all underwent blink reflex on affected/healthy sides and TSEP examinations. The diagnostic value of the blink reflex combined with TSEP was analyzed. Results: The latency of R1, R2, and R2' waves (refers to the different nerve signal waveforms that are recorded when a facial nerve conduction speed test is performed) on the affected side was significantly longer than that on the healthy side (t = 26.324, 18.391, 20.801,Ps < .001), and latency of W1, W2 and W3 waves was also significantly longer than that on the healthy side (t = 16.045, 10.814, 10.349, P < .001). The results of Pearson correlation analysis showed that the latency of R1, W1, W2, and W3 waves was positively correlated with the VAS score (r = 0.539, 0.611, 0.577, 0.586, P < .001). The results of receiver operating characteristic (ROC) curves analysis showed that area under the curve (AUC) values of R1, R2, R2', W1, W2, and W3 waves latency on the affected side in the diagnosis of trigeminal neuralgia were 0.753, 0.634, 0.651, 0.748, 0.756 and 0.736, respectively. The AUC of combined detection was 0.926, significantly greater than that of the single index (P < .001). Conclusion: Blink reflex combined with TSEP monitoring can improve the diagnostic value of trigeminal neuralgia, and the latency is related to pain.

Sampling Gaussian stationary random fields: A stochastic realization approach.

Generating large-scale samples of stationary random fields is of great importance in the fields such as geomaterial modeling and uncertainty quantification. Traditional methodologies based on covariance matrix decomposition have the difficulty of being computationally expensive, which is even more serious when the dimension of the random field is large. This paper proposes an efficient stochastic realization approach for sampling Gaussian stationary random fields from a systems and control point of view. Specifically, we take the exponential and squared exponential covariance functions as examples and make a decoupling assumption when there are multiple dimensions. Then a rational spectral density is constructed in each dimension using techniques from covariance extension, and the corresponding autoregressive moving-average (ARMA) model is obtained via spectral factorization. As a result, samples of the random field with a specific covariance function can be generated very efficiently in the space domain by implementing the ARMA recursion using a Gaussian white noise input. Such a procedure is computationally cheap due to the fact that the constructed ARMA model has a low order. Furthermore, the same method is integrated to multiscale simulations where interpolations of the generated samples are achieved when one zooms into finer scales. Both theoretical analysis and simulation results show that our approach performs favorably compared with covariance matrix decomposition methods.