Subsequent Dissociation Research Articles

Photo-responsive hole formation in the monolayer membrane wall of a supramolecular nanotube for quick recovery of encapsulated protein.

Nanotubes with a single monolayer membrane wall comprised of a synthetic glycolipid and one of two synthetic azobenzene derivatives were assembled. X-ray diffraction, infrared, UV-visible, and circular dichroism spectroscopy clarified the embedding style of the azobenzene derivatives in the membrane wall, revealing that, depending on their different intermolecular hydrogen bond strengths, one azobenzene derivative was individually dispersed whereas the other formed a J-type aggregate. The non-aggregated derivative was insensitive to UV irradiation due to tight fixation by the surrounding glycolipid. In contrast, the aggregated derivative was sensitive to UV irradiation, which induced trans-to-cis isomerization of the derivative and disassembly of the J-type aggregate. Subsequent dissociation of the derivative into the bulk solution resulted in the formation of many nanometer-scale holes in the membrane wall. Although a model protein encapsulated within the nanotubes was slowly released over time from the two open ends of the nanotubes without UV irradiation, exposure to UV irradiation resulted in faster, preferential release of the protein through the holes in the membrane wall. The present findings are expected to facilitate the development not only of efficient means of recovering guest compounds stored within nanotubes but also the development of novel stimuli-responsive capsules in biological and medical fields.

Oxidation Dynamics of Supported Catalytic Cu Clusters: Coupling to Fluxionality

Copper oxide nanoclusters have a wide range of catalytic applications, such as the selective oxidation of hydrocarbons. O2 binding to the catalyst, activation, and release upon reagent oxidation are key events in these catalytic chemistries. These events are expected to be accompanied by significant structural changes of the Cu clusters, because O atoms integrate into the cluster, rather than bind to its surface. Topping the complexity of the problem, partially oxidized Cu clusters are known to exhibit strong fluxionality and feature diverse and interconverting structures and oxygen contents in conditions of oxidative dehydrogenation (ODH). Hence, a significant dynamic coupling between the “hot” O2 molecule impacting the cluster at reaction temperatures and the cluster fluxionality can be expected. In this work, we focus on the dynamics of dioxygen integration into a partially oxidized Cu cluster supported on hydroxylated amorphous alumina–a system recently reported to be an exceptionally selective catalyst for cyclohexane ODH with very little CO produced, whose mechanistic underpinnings are of utmost interest. The statistics over a swarm of adsorption and scattering trajectories where O2 hits various sites on the cluster at reaction temperature shows that the O2 binding does not only follow the minimal energy paths. O2 also rarely integrates into the cluster in a single step and instead first binds to a single Cu atom via either an η1-O2 or an η2-O2 mode. Surprisingly, this step often has a higher barrier than the subsequent O2 integration and dissociation, which in turn take multiple steps and complete the oxidation process. Dynamic trajectories starting from the key transition state of integration of the adsorbed O2 can also lead to different intermediate structures during or right after the dissociation, due to the energy released from the transition state and the thermal intracluster effects. From these activated O2 chemisorbed structures, O2 dissociation occurs with moderate barriers (∼0.5 eV), producing multiple final oxidized Cu4O4 states. Hence, a diversity of reaction profiles for the attack of supported Cu cluster by O2 emerges due to the dynamic effects, with implications for mechanisms, kinetic models, and catalyst design principles.

The σ1 Receptor and the HINT1 Protein Control α2δ1 Binding to Glutamate NMDA Receptors: Implications in Neuropathic Pain.

Nerve injury produces neuropathic pain through the binding of α2δ1 proteins to glutamate N-methyl-D-aspartate receptors (NMDARs). Notably, mice with a targeted deletion of the sigma 1 receptor (σ1R) gene do not develop neuropathy, whereas mice lacking the histidine triad nucleotide-binding protein 1 (Hint1) gene exhibit exacerbated allodynia. σ1R antagonists more effectively diminish neuropathic pain of spinal origin when administered by intracerebroventricular injection than systemically. Thus, in mice subjected to unilateral sciatic nerve chronic constriction injury (CCI), we studied the participation of σ1Rs and HINT1 proteins in the formation of α2δ1-NMDAR complexes within the supraspinal periaqueductal gray (PAG). We found that δ1 peptides required σ1Rs in order to interact with the NMDAR NR1 variant that contains the cytosolic C1 segment. σ1R antagonists or low calcium levels provoke the dissociation of σ1R-NR1 C1 dimers, while they barely affect the integrity of δ1-σ1R-NR1 C1 trimers. However, HINT1 does remove δ1 peptides from the trimer, thereby facilitating the subsequent dissociation of σ1Rs from NMDARs. In σ1R−/− mice, CCI does not promote the formation of NMDAR-α2δ1 complexes and allodynia does not develop. The levels of α2δ1-σ1R-NMDAR complexes increase in HINT1−/− mice and after inducing CCI, degradation of α2δ1 proteins is observed. Notably, σ1R antagonists but not gabapentinoids alleviate neuropathic pain in these mice. During severe neuropathy, the metabolism of α2δ1 proteins may account for the failure of many patients to respond to gabapentinoids. Therefore, σ1Rs promote and HINT1 proteins hinder the formation α2δ1-NMDAR complexes in the PAG, and hence, the appearance of mechanical allodynia depends on the interplay between these proteins.

Activation of Molecular O2 on CoFe2 O4 (001) Surfaces: An Embedded Cluster Study.

Dioxygen activation pathways on the (001) surfaces of cobalt ferrite, CoFe2O4, were investigated computationally using density functional theory and the hybrid Perdew‐Burke‐Ernzerhof exchange‐correlation functional (PBE0) within the periodic electrostatic embedded cluster model. We considered two terminations: the A‐layer exposing Fe2+ and Co2+ metal sites in tetrahedral and octahedral positions, respectively, and the B‐layer exposing octahedrally coordinated Co3+. On the A‐layer, molecular oxygen is chemisorbed as a superoxide on the Fe monocenter or bridging a Fe−Co cation pair, whereas on the B‐layer it is adsorbed at the most stable anionic vacancy. Activation is promoted by transfer of electrons provided by the d metal centers onto the adsorbed oxygen. The subsequent dissociation of dioxygen into monoatomic species and surface reoxidation have been identified as the most critical steps that may limit the rate of the oxidation processes. Of the reactive metal‐O species, [FeIII−O]2+ is thermodynamically most stable, while the oxygen of the Co−O species may easily migrate across the A‐layer with barriers smaller than the associative desorption.

Experimental observation of formation and dissociation of methane hydrate in a micromodel

Understanding the mechanisms of hydrate formation and dissociation is significant for natural gas hydrate exploration. In this study, a porous micromodel was used to visualize the formation and dissociation of methane hydrate in methane-pure water and methane-brine systems via a microfluidic approach. Various methane hydrates with different growth characteristics were formed, which may result from variations in the sizes and distributions of methane bubbles. The differences in the mode of methane hydrate formation were associated with various phenomena during hydrate dissociation. The size, number and size distribution of the dissociated methane bubbles were quantitatively analyzed to describe hydrate dissociation behavior. Hydrate dissociation in the methane-brine system differed significantly from that in the methane-pure water system. Furthermore, multiple formation-dissociation processes of methane hydrate were investigated. The results indicated that multiple formation-dissociation processes can significantly impact the characteristics of the gas–liquid interfaces, which could influence the subsequent hydrate formation and dissociation behaviors.

Predicting pacemaker dependency after TAVI with pre-procedural MSCT

Abstract Background and aim High degree conduction disturbances is a burdensome complication of transcatheter aortic valve implantation (TAVI). There is limited data whether such disorders are permanent or reversible. Anatomic surrogates, such as membranous septum [MS, a distance marker from aortic annulus to His-bundle surge] and calcium distribution within aortic valve have been associated with pacemaker (PM) implantation. The aim of our study was to assess predictors of long-term pacemaker dependency following TAVI. Methods Single center prospectively included patients that underwent pacemaker implantation following TAVI (March 2017 to September 2020). Patients who were lost to follow up, with bicuspid aortic valve, previously implanted PM and non-available or low quality MSCT exam were excluded. On MSCT, MS length was measured on modified coronal view, the aortic-valvular complex (AVC) was characterized by leaflet sector and calcium distribution was assessed on a J-score threshold of 850-Hounsfield units. Pacemaker dependency was assessed by reducing ventricular pacing to 30 bpm and defined by subsequent complete AV dissociation in patients in sinus rhythm or an escape rhythm <50 bpm in atrial fibrillation, in addition of >90% pacing percentage since implantation. Results From the 352 patients with inclusion criteria, 67 underwent PM implantation (19%) and 55 included in the analysis (male 33.9%, median age=85) (Figure). Median time for pacemaker implantation was 3 days [interquartile range (IQR) 3–5 days], mostly due to complete auriculo-ventricular block (76.4%, N=42). PM dependency occurred in 14 out of 55 (25.5%) patients at mean follow up of 500±363 days. Patients with PM dependency tended to have deeper implantation depth, (6.2 mm vs 5.5 mm, p=0.096) and a significantly shorter MS (5.8 mm vs 6.8 mm, P-value = 0.031) (Table). Increasing MS length was independently associated with a lower risk of PM dependency [odds ratio (OR) 0.58 per mm; 95% CI: 0.35–0.98, p=0.04] regardless prosthesis choice. MS length under 5 mm had 97.6% specificity (95% CI: 87.1–99.9) and 85.7% positive predictive value for pacemaker dependency (AUC=76.7; 95% CI 63.3–87). Conclusion Our findings highlight the importance of MSCT-derived MS length to stratify the risk of long term need for pacemaker. Patients with short MS (<5mm) in addition to conduction abnormality following TAVI had a high likelihood of PM dependency on the long term and should be considered for prompt PM implantation. Funding Acknowledgement Type of funding sources: None.

Theoretically predicted CO adsorption and dissociation on Ru-doped Co(1 0 0) surfaces

CO adsorption and dissociation on Ru-doped Co(100) surfaces at different CO coverage compared to clean surface were investigated based on spin-polarized density functional theory (DFT), in order to explore the effect of the initial step of Ru promoter on CO activation in cobalt-based Fischer-Tropsch synthesis (FTS). The results show that CO adsorption is highly site-dependent, the adsorption strength of CO at different types of adsorption sites is determined by the interaction between the adsorbed CO molecule and Ru-doped Co(100) surfaces. CO dissociation is promoted at hollow sites but inhibited at top and bridge sites above the Ru atoms. In addition, the amount of saturated adsorbed CO is increased while the amount of dissociated CO is decreased on the Ru-doped Co(100) surfaces at high coverage. Combining the experimental results, it is concluded that the adsorption model is preferred than substitution model for CO activation, because the increased CO molecular states in adsorption model is facile for the subsequent H-assisted dissociation on Co surface. The present work suggests that the addition of Ru promoter can improve the CO activation on Co(100) surface and pave the way for experimental research.

Anti-Atherosclerotic Effect of Gossypetin on Abnormal Vascular Smooth Muscle Cell Proliferation and Migration.

Gossypetin (GTIN), known as 3,5,7,8,3′,4′-hexahydroxyflavone, has been demonstrated to exert anti-atherosclerotic potential against apoptotic injury in oxidized low-density lipoprotein-incubated endothelial cells, and atherosclerotic lesions of cholesterol-fed rabbits. However, the effect and underlying mechanism of GTIN on abnormal vascular smooth muscle cells (VSMCs) proliferation and migration, a major event in the pathogenesis of atherosclerosis, is still unknown. In this study, non-cytotoxic doses of GTIN abolished the VSMCs A7r5 proliferation and cell-cycle S phase distribution. The GTIN-arrested G0/G1 phase might be performed by increasing the expressions of phosphorylated p53 and its downstream molecules that inhibit the activation of cyclin E/cyclin-dependent kinase (cdk)-2, blocking retinoblastoma protein (Rb) phosphorylation and the subsequent dissociation of Rb/transcription factor E2F1 complex. In addition, the results indicated that GTIN inhibited VSMCs wound-healing and migratory abilities through reducing matrix metalloproteinase (MMP)-9 activity and expression, as well as down-regulating protein kinase B (PKB)/nuclear factor-kappaB (NF-κB) signaling. GTIN also revealed potential in diminishing reactive oxygen species (ROS) generation. These findings suggested the inhibitory effects of GTIN on VSMCs dysfunction could likely lead to the containment of atherosclerosis and other cardiovascular illness.

Dissociation dynamics in chloroform molecule induced by ion impact

The ion impact multiple ionization and subsequent dissociation of Chloroform (CHCl3) is investigated with Ar7+ ion beam having an energy of 1 MeV. Using a linear time of flight mass spectrometer coupled with a position sensitive detector, complete as well as incomplete Coulomb explosion pathways for CHCl32+ and CHCl33+ ions are identified and studied. Possible modes of fragmentation pathway for all the identified channels are investigated with the help of kinetic energy release and momentum distributions of fragmented ions. Although concerted fragmentation is the most dominant pathway within the identified channels, we have discussed the possibilities of sequential processes which may occur. A positive slope between the coincidence partners of H+ and C+ probably features sequentiality in the breakup dynamics but remain inconclusive due to lack of complete information. Formation of Cl2+ from the doubly charged CHCl32+ is a direct evidence of bond rearrangement reaction following a structural change during charge separation.

Theoretical insights of catalytic oxidation of Hg0 on g-C3N4-supported Fe/Co/Ni-based bi-metallic catalysts using O2 in coal-fired flue gas as the oxidant

In this work, density functional theory (DFT) calculations were conducted to investigate the adsorption and oxidation of Hg0 with O2 as the oxidant on pristine and O-adsorbed dimers of Fe, Co and Ni supported on the buckled g-C3N4 surface. The calculation reveals that all the dimers supported on the buckled g-C3N4 surface (Fe2/Co2/Ni2@g-C3N4) are stable at 700 K. It is found that Hg0 oxidation starts from the adsorption of O2 and its subsequent dissociation, followed by the formation of OHgO and the desorption of HgO from the surface. However, after desorption of the first HgO, the active site of the dimer becomes an O-adsorbed dimer, which affects - Hg0 oxidation reaction although the reaction pathway is similar. DFT calculations demonstrate that both the pristine dimer and O-adsorbed dimer are effective in O2 dissociation and are relatively easy for the metal-O bond to break, which is associated with a low energy barrier for these two processes. However, the interactions between O2/Hg0 and the pristine surface are significantly stronger than those between O2/Hg0 and the O-adsorbed dimer site. Rate-determining step of catalytic oxidation process on the pristine and O-adsorbed Fe2@g-C3N4 and Co2@g-C3N4 is the cleavage of the metal-O bond, while the HgO desorption dominates the pristine and O-adsorbed Ni2@g-C3N4 with an energy barrier of 2.04 eV and 1.62 eV, respectively. It is found that among the dimers studied, the Ni2@g-C3N4 exhibites the highest efficiency in the catalytic oxidation of Hg0.

Hydrodeoxygenation of aliphatic acid over NiFe intermetallic compounds: Insights into the mechanism via model compound study

Hydrodeoxygenation (HDO) is a promising way to produce the second generation bio-diesel from aliphatic acid based biomass. Compared with the monometallic Ni/SiO2, appropriate introduction of Fe results in the complete conversion of lauric acid and nearly 100% yield of alkane as well as satisfactory stability on conversion. Further study on mechanism shows that the NiFe intermetallic compounds (IMC) catalyst promotes the ratedetermining step, i.e., C11H23COOH → C11H23CHO, which is attributed to the synergistic effect of Ni-Fe bimetallic sites according to the characterization and calculation. For one thing, strong spin polarization enhances the interaction between Fe sites and aliphatic acid, and the subsequent dissociation of C-OH bond indicated by the DOS and transition state analysis. For another, dissociation of H2 on Ni site is promoted because of the higher charge density around Ni in the IMC according to the in-suit FTIR and Bader analysis. However, with the repeated use of the catalyst, the selectivity to alkane decreased gradually, which is ascribed to the oxidation of metal Ni-Fe bimetallic sites. This demonstrates that the reduced Ni-Fe bimetallic sites rather than the oxidized ones are the active phases in the HDO of aliphatic acid to produce alkanes with the NiFe IMC.

Atomically Dispersed Manganese Lewis Acid Sites Catalyze Electrohydrogenation of Nitrogen to Ammonia

Atomically Dispersed Manganese Lewis Acid Sites Catalyze Electrohydrogenation of Nitrogen to Ammonia

Dissection of Alkylpyridinium Structures to Understand Deamination Reactions.

Via conversion to Katritzky pyridinium salts, alkyl amines can now be used as alkyl radical precursors for a range of deaminative functionalization reactions. The key step of all these methods is single electron reduction of the pyridinium ring, which triggers C-N bond cleavage. However, little has been done to understand how the precise nature of the pyridinium influences these events. Using a combination of synthesis, computation, and electrochemistry, this study delineates the steric and electronic effects that substituents have on the canonical steps and the overall process. Depending on the approach taken, consideration of both the reduction and the subsequent radical dissociation may be necessary. Whereas the electronic effects on these steps work in opposition to each other, the steric effects are synergistic, with larger substituents favoring both steps. This understanding provides a framework for future design of pyridinium salts to match the mode of catalysis or activation.

High-Temperature Fluorocarbon Chemistry Revisited.

The thermal dissociation reactions of C2F4 and C2F6 were studied in shock waves over the temperature range 1000-4000 K using UV absorption spectroscopy. Absorption cross sections of C2F4, CF2, CF, and C2 were derived and related to quantum-chemically modeled oscillator strengths. After confirming earlier results for the dissociation rates of C2F4, CF3, and CF2, the kinetics of secondary reactions were investigated. For example, the reaction CF2 + CF2 → CF + CF3 was identified. Its rate constant of 1010 cm3 mol-1 s-1 near 2400 K is markedly larger than the limiting high-pressure rate constant of the dimerization CF2 + CF2 → C2F4, suggesting that the reaction follows a different path. When the measurements of the thermal dissociation CF2 (+Ar) → CF + F (+Ar) are extended to temperatures above 2500 K, the formation of C2 radicals was shown to involve the reaction CF + CF → C2F + F (modeled rate constant 8.0 × 1012 (T/3500 K)1.0 exp(-4400 K/T) cm3 mol-1 s-1) and the subsequent dissociation C2F (+Ar) → C2 + F + (Ar) (modeled limiting low-pressure rate constant 3.0 × 1016 (T/3500 K)-4.0 exp(-56880 K/T) cm3 mol-1 s-1). This mechanism was validated by monitoring the dissociation of C2 at temperatures close to 4000 K. Temperature- and pressure-dependences of rate constants of reactions involved in the system were modeled by quantum-chemistry based rate theory.

Initial Thermal Decomposition Mechanism of (NH2)2C=C(NO2)(ONO) Revealed by Double-Hybrid Density Functional Calculations.

This work employs double-hybrid density functionals to re-examine the CO–NO bond dissociation mechanism of nitrite isomer of 1,1-diamino-2,2-dinitro-ethylene (DADNE) into (NH2)2C=C(NO2)O and nitric monoxide (NO). The calculated results confirm that an activated barrier is present in the CO–NO bond dissociation process of (NH2)2C=C(NO2)(ONO). Furthermore, it is proposed that a radical–radical adduct is involved in the exit dissociation path with subsequent dissociation to separate (NH2)2C=C(NO2)O and NO radicals. The activation and reaction enthalpies at 298.15 K for the nitrite isomer dissociation are predicted to be 43.6 and 5.4 kJ mol–1 at the B2PLYP/6-31G(d,p) level, respectively. Employing the B2PLYP/6-31G(d,p) reaction energetics, gradient, Hessian, and geometries, the kinetic model for the CO–NO bond dissociation of (NH2)2C=C(NO2)(ONO) is obtained by a fitting to the modified Arrhenius form 1.05 × 1013(T/300)0.39 exp[−27.80(T + 205.32)/R(T2 + 205.322)] in units of per second over the temperature range 200–3000 K based on the canonical variational transition-state theory with multidimensional small-curvature tunneling.

Comprehensive kinetic model for acetylene pretreated mesoporous silica supported bimetallic Co-Ni catalyst during Fischer-Trospch synthesis

A new model by incorporating the porosity field during acetylene pretreatment (PT) into the Fischer-Trospch (FT) synthesis comprehensive kinetic is proposed for quantitatively describing the product distributions using a mesoporous silica supported Co-Ni bimetallic catalyst. Coupling the quasi-homogeneous medium model with the acetylene reaction kinetics via the Langmuir-Hinshelwood-Hougen-Watson (LHHW) approach, the model yields good predictions for breakthrough curves, pressure drops, and permeability during PT process. The active carbidic intermediates formed by the acetylene PT engaged with the subsequent CO dissociation and 1-olefin re-adsorption associated secondary reactions during FT synthesis. The constructed comprehensive kinetic model can predict the olefin to paraffin ratios (OPR) versus chain length when the catalyst was pretreated. A relatively good prediction from chain length dependent model (CLD) indicates the validity of assuming that Van Waals forces play a critical role during olefin re-adsorption in the secondary reactions for chain propagations once the mesoporous supported Co-Ni bimetallic catalyst was pretreated by acetylene. The proposed model successfully bridges the gaps between the PT and FT process at the investigated experimental conditions.

Enhancing Electrochemical CO2 Reduction using Ce(Mn,Fe)O2 with La(Sr)Cr(Mn)O3 Cathode for High‐Temperature Solid Oxide Electrolysis Cells

AbstractRobust oxide electrodes with high activity and durability have attracted significant attention as alternatives for Ni‐based cathodes in high‐temperature solid oxide electrolysis cells (SOECs). Noncoking La(Sr)Cr(Mn)O3 (LSCM)‐based oxide cathodes have shown promise as durable ceramic cathodes; however, they suffer from low electrocatalytic activities in electrochemical CO2 reduction. In this study, a dual‐phase composite electrode consisting of LSCM and Ce(Mn, Fe)O2 (CMF) is developed to enhance the electrocatalytic activity of CO2 reduction in SOECs. The developed electrode shows excellent electrolysis performance of 2.64 and 1.22 A cm–2 at 1123 K, when voltages of 1.5 and 1.2 V are applied, respectively, without using any precious metal catalysts. The enhanced electrolysis performance is attributed to increases in electrocatalytic activity and surface oxygen vacancies caused by the CMF, which accelerates CO2 adsorption and results in the subsequent dissociation of the carbonate intermediate in the CO2 reduction.

Strong-field ionization of water: Nuclear dynamics revealed by varying the pulse duration

Polyatomic molecules in strong laser fields can undergo substantial nuclear motion within tens of femtoseconds. Ion imaging methods based on dissociation or Coulomb explosion therefore have difficulty faithfully recording the geometry dependence of the field ionization that initiates the dissociation process. Here we compare the strong-field double ionization and subsequent dissociation of water (both H$_2$O and D$_2$O) in 10-fs and 40-fs 800-nm laser pulses. We find that 10-fs pulses turn off before substantial internuclear motion occurs, whereas rapid internuclear motion can take place during the double ionization process for 40-fs pulses. The short-pulse measurements are consistent with a simple tunnel ionization picture, whose predictions help interpret the motion observed in the long-pulse measurements.

An (e, 2e + ion) study of electron-impact ionization and fragmentation of carbon dioxide clusters

We report an experimental study of the electron-impact ionization (E 0 = 65 eV) and fragmentation of carbon dioxide clusters for the formation of and using a reaction microscope. All three charged particles, two outgoing electrons and one cation, are detected in coincidence such that the momentum vectors and, consequently, the kinetic energies for these final-state particles are determined. The reaction mechanisms correlated to ionic species are analyzed using the measured binding energy spectra over a broad range of ionization energy (8–32 eV). We observe that the cations with small momenta are formed mainly from the direct ionization of the outermost 1π g orbital in the carbon dioxide dimer (CO2)2. While the (1π u )−1, (3σ u )−1 and (4σ g )−1 states in are unstable and most likely dissociate into and neutral species. The cations with high momenta are attributed to the ionization of small carbon dioxide clusters (CO2) n (n ⩾ 3) and subsequent dissociation processes. Compared to the appearance energy studies of carbon dioxide clusters where only the outermost 1π g orbital ionization was observed for formation of , several additional channels are identified in this work.

Marine Gas Hydrate Geohazard Assessment on the European Continental Margins. The Impact of Critical Knowledge Gaps

This paper presents a geohazard assessment along the European continental margins and adjacent areas. This assessment is understood in the framework of the seafloor’s susceptibility to (i.e., likelihood of) being affected by the presence of hydrate deposits and the subsequent hazardous dissociation processes (liquefaction, explosion, collapse, crater-like depressions or submarine landslides). Geological and geophysical evidence and indicators of marine gas hydrates in the theoretical gas hydrate stability zone (GHSZ) were taken into account as the main factors controlling the susceptibility calculation. Svalbald, the Barents Sea, the mid-Norwegian margin-northwest British Islands, the Gulf of Cádiz, the eastern Mediterranean and the Black Sea have the highest susceptibility. Seafloor areas outside the theoretical GHSZ were excluded from this geohazard assessment. The uncertainty analysis of the susceptibility inference shows extensive seafloor areas with no data and a very low density of data that are defined as critical knowledge gaps.