Structure-Based Design and Preclinical Characterization of Selective and Orally Bioavailable Factor
Explore the source record for details and available documents.
Lorthiois, Edwige↗
Engineering topics
Liu, Hong
Publications and source records attributed to Liu, Hong.
Breaking the loop: Tackling homoacetogenesis by chloroform to halt hydrogen production-consumption loop in single chamber microbial electrolysis cells
The presence of homoacetogenesis and hydrogen production-consumption loop significantly hinders the efficient hydrogen recovery in single chamber microbial electrolysis cells (MECs). Furthermore, no effective inhibition method has been proposed against homoacetogens hitherto. In this study, we demonstrated the effectiveness of chloroform as a homoacetogen inhibitor in MECs. In small MECs (320 ml) operated in batch mode, chloroform with concentrations of 0.02% (v/v) and 0.03% (v/v) ceased homoacetogenesis with nonfermentable substrate (acetate), enhancing hydrogen yield and cathodic hydrogen recovery from 21% and 14% to 94% and 90%, respectively. Electrochemical performance was not significantly affected as current density (based on anode surface area) only decreased from 18 A/m 2 to 13 A/m 2 with chloroform concentration increased from 0% (v/v) to 0.03% (v/v). However, when using a fermentable substrate (glucose), the inhibition against homoacetogens by 0.01% (v/v) chloroform led to a significant decrease in current density possibly due to the decreased production of acetate, which reduced the substrate concentration for exoelectrogenesis. Nevertheless, in a larger MEC (10 L), using an immobilized sludge culture and higher glucose concentration (56mM), 0.02% (v/v) chloroform enhanced hydrogen production rate from 0 L/L/D to 4.9 L/L/D and current density from 12-16 A/m 2 to 18-21 A/m 2 . Microbial community analysis revealed that the amount of homoacetogenic Acetobacterium spp. was eliminated in the cathodic biofilms and planktonic cells by chloroform. Future improvement of this method, through reducing the residual chloroform concentration and developing more environment friendly inhibitor using similar mechanisms, may lead to the practical application in MECs.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Ensuring Flexibility and Security in SDN-Based Spacecraft Communication Networks Through Risk Assessment
Software-defined networking (SDN) has enabled elastic networking and resource distribution in cloud computing. The centralization and separation of the Control Plane also offers a high degree of network configurability and management, which can be used to mitigate and manage threats to the network. Space communication networks have historically been restricted and circuit switching in these networks has been a manual process. This study evaluates the potential role of SDN in space communication networks from a networking security standpoint. The evaluation covers the networking security needs of spacecraft missions and their associated assets. The results from the evaluation lead to a risk assessment that identifies vulnerabilities in an SDN-based communications architecture. Security challenges introduced into the network from integrating SDN are also considered. A risk register summarizes the severity of the attack outcomes, as well as occurrence likelihood. The study identifies Denial-of-Service (DoS) attacks as a new threat (presently unmitigated by existing security controls) that would be prevalent in an SDN-based space communication environment. A Mininet-based emulation testbed is built to demonstrate the susceptibility of spacecraft flight software to a flooding DoS attack when on an interconnected SDN-managed network. This type of attack would be highly consequential to mission assets, and therefore SDN-based space communications would need to be resilient to such attacks. Future work will need to be performed to fully characterize DoS attack methods that can apply to the space communication scenario, as well as to devise a comprehensive DoS-resilient solution.
Baker, Dylan Z.↗
Regenesis and quantum traversable wormholes
Recent gravity discussions of a traversable wormhole indicate that in holographic systems signals generated by a source could reappear long after they have dissipated, with the need of only performing some simple operations. In this paper we argue the phenomenon, to which we refer as “regenesis”, is universal in general quantum chaotic many-body systems, and elucidate its underlying physics. The essential elements behind the phenomenon are: (i) scrambling which in a chaotic system makes out-of-time-ordered correlation functions (OTOCs) vanish at large times, (ii) the entanglement structure of the state of the system. The latter aspect also implies that the regenesis phenomenon requires fine tuning of the initial state. Compared to other manifestations of quantum chaos such as the initial growth of OTOCs which deals with early times, and a random matrix-type energy spectrum which reflects very large time behavior, regenesis concerns with intermediate times, of order the scrambling time of a system. We also study the phenomenon in detail in general two-dimensional conformal field theories in the large central charge limit, and highlight some interesting features including a resonant enhancement of regenesis signals near the scrambling time and their oscillations in coupling. Finally, we discuss gravity implications of the phenomenon for systems with a gravity dual, arguing that there exist regimes for which traversability of a wormhole is quantum in nature, i.e. cannot be associated with a semi-classical spacetime causal structure.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Electrocatalytic Hydrogen Evolution in Neutral pH Solutions: Dual-Phase Synergy
Electrolysis in neutral pH solutions (e.g., wastewater and seawater) presents a transformative way for environmentally friendly, cost-effective hydrogen production. However, one of the biggest challenges is the lack of active, robust hydrogen evolution reaction (HER) catalysts. Herein we present a catalyst with dual active sites of MoP2 and MoP which function synergistically to promote HER in neutral pH solutions. In our microbial electrolysis cell (MEC) which uses neutral pH wastewater as a feedstock, the new catalyst generates an average HER current density of ~157 A m-2Cathode-Surface-Area, higher than Pt/C (~145 A m-2Cathode-Surface-Area), ~5 times higher than the state-of-art platinum-group-metal (PGM)-free catalysts in MECs. The new catalyst also outperforms Pt/C in natural seawater with ~10% higher and more stable HER current density. The fundamental reason for the enhanced HER performance is identified to be the synergy between MoP2 and MoP phases, with MoP2 promoting H2O chemisorption/dissociation and MoP efficiently converting Hads to H2.
Xie, Xiaohong↗
Heterojunction Architecture of N‐Doped WO 3 Nanobundles with Ce 2 S 3 Nanodots Hybridized on a Carbon Textile Enables a Highly Efficient Flexible Photocatalyst
Abstract The availability of robust, versatile, and efficient photocatalysts is the main bottleneck in practical applications of photocatalytic degradation of organic pollutants. Herein, N‐WO 3 /Ce 2 S 3 nanotube bundles (NBs) are synthesized and successfully immobilized on a carbon textile, resulting in a flexible and conducting photocatalyst. Due to the large interfacial area between N‐WO 3 and Ce 2 S 3 , the interwoven 3D carbon architecture and, more importantly, the establishment of a heterojunction between N‐WO 3 and Ce 2 S 3 , the resultant photocatalyst exhibits excellent light absorption capacity and superior ability to separate photoinduced electron–hole pairs for the photocatalytic degradation of organic compounds in air and water media. Theoretical calculations confirm that the strong electronic interaction between N‐WO 3 and Ce 2 S 3 can be beneficial to the enhancement of the charge carrier transfer dynamics of the as‐prepared photocatalyst. This work provides a new protocol for constructing efficient flexible photocatalysts for application in environmental remediation.
Huang, Yongchao↗
Microstructural Characteristics and Mechanical Properties in the Laser Beam Welded Joints of High-Strength Microalloyed Steel
The laser beam welded joints of the high-strength microalloyed steel consist of the base metal (BM), the partially transformed heat-affected zone I (PTHAZ-I), the partially transformed heat-affected zone II (PTHAZ-II), the fully transformed heat-affected zone (FTHAZ) and the fusion zone (FZ). The martensite/austenite (M/A) islands of the bainites in the PTHAZ-II are dense versus those in the PTHAZ-I, and the martensites exist in the FTHAZ and the FZ together with the bainites under the slow welding speed. The M/A islands of the bainites and/or the martensites in the PTHAZ become denser under the high welding speed, and the martensites in the FTHAZ and the FZ predominate. The low-angle boundary density and the high local misorientation proportion are used to identify the constituents roughly, consistent with the microstructural characteristics in the welded joints. The misorientation angle distributions are employed to evaluate the degree of the phase transformation, reflecting the change law of the degree of the phase transformation in the welded joints. The hardness and the tensile tests indicate that the HAZ and the FZ are stronger than the BM, dependent on the microstructures in the welded joints. The strengthening in the HAZ and the FZ is mainly attributed to the products of non-equilibrium phase transformation with the high dislocation density.
36 MATERIALS SCIENCE↗
Linking internal resistance with design and operation decisions in microbial electrolysis cells
Not Available
54 ENVIRONMENTAL SCIENCES↗
Temperature-induced amorphization in CaCO 3 at high pressure and implications for recycled CaCO 3 in subduction zones
Calcium carbonate (CaCO 3 ) significantly affects the properties of upper mantle and plays a key role in deep carbon recycling. However, its phase relations above 3 GPa and 1000 K are controversial. Here we report a reversible temperature-induced aragonite-amorphization transition in CaCO 3 at 3.9-7.5 GPa and temperature above 1000 K. Amorphous CaCO 3 shares a similar structure as liquid CaCO 3 but with much larger C-O and Ca-Ca bond lengths, indicating a lower density and a mechanism of lattice collapse for the temperature-induced amorphous phase. The less dense amorphous phase compared with the liquid provides an explanation for the observed CaCO 3 melting curve overturn at about 6 GPa. Amorphous CaCO 3 is stable at subduction zone conditions and could aid the recycling of carbon to the surface.
58 GEOSCIENCES↗
Characterizing hydrodynamical fluctuations in heavy-ion collisions from effective field theory approach
Hydrodynamic fluctuations are found to be important in many situations such as cosmology, condensed matter system and heavy-ion collisions. Recently, an effective field theory for fluctuating dissipative hydrodynamics has been developed in 1511.03646 and 1701.07817. We apply this theory to investigate nontrivial consequences of hydrodynamic fluctuations on the Bjorken expanding quark gluon plasma (QGP). In particular, we explore nontrivial effects due to interactions among hydrodynamical variables and noises which are systematically incorporated in the present framework but are not fully captured in conventional approaches.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Global anomalies, discrete symmetries and hydrodynamic effective actions
We derive effective actions for parity-violating fluids in both (3 + 1) and (2 + 1) dimensions, including those with anomalies. As a corollary we confirm the most general constitutive relations for such systems derived previously using other methods. We discuss in detail connections between parity-odd transport and underlying discrete symmetries. In (3+1) dimensions we elucidate connections between anomalous transport coefficients and global anomalies, and clarify a previous puzzle concerning transports and local gravitational anomalies.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
A quantum hydrodynamical description for scrambling and many-body chaos
Recent studies of out-of-time ordered thermal correlation functions (OTOC) in holographic systems and in solvable models such as the Sachdev-Ye-Kitaev (SYK) model have yielded new insights into manifestations of many-body chaos. So far the chaotic behavior has been obtained through explicit calculations in specific models. In this paper we propose a unified description of the exponential growth and ballistic butterfly spreading of OTOCs across different systems using a newly formulated “quantum hydrodynamics,” which is valid at finite ℏ and to all orders in derivatives. The scrambling of a generic few-body operator in a chaotic system is described as building up a “hydrodynamic cloud,” and the exponential growth of the cloud arises from a shift symmetry of the hydrodynamic action. The shift symmetry also shields correlation functions of the energy density and flux, and time ordered correlation functions of generic operators from exponential growth, while leads to chaotic behavior in OTOCs. The theory also predicts an interesting phenomenon of the skipping of a pole at special values of complex frequency and momentum in two-point functions of energy density and flux. This pole-skipping phenomenon may be considered as a “smoking gun” for the hydrodynamic origin of the chaotic mode. Here, we also discuss the possibility that such a hydrodynamic description could be a hallmark of maximally chaotic systems.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Allele-defined genome of the autopolyploid sugarcane Saccharum spontaneum L.
Modern sugarcanes are polyploid interspecific hybrids, combining high sugar content from Saccharum officinarum with hardiness, disease resistance and ratooning of Saccharum spontaneum. Sequencing of a haploid S. spontaneum, AP85-441, facilitated the assembly of 32 pseudo-chromosomes comprising 8 homologous groups of 4 members each, bearing 35,525 genes with alleles defined. The reduction of basic chromosome number from 10 to 8 in S. spontaneum was caused by fissions of 2 ancestral chromosomes followed by translocations to 4 chromosomes. Surprisingly, 80% of nucleotide binding site-encoding genes associated with disease resistance are located in 4 rearranged chromosomes and 51% of those in rearranged regions. Resequencing of 64 S. spontaneum genomes identified balancing selection in rearranged regions, maintaining their diversity. Introgressed S. spontaneum chromosomes in modern sugarcanes are randomly distributed in AP85-441 genome, indicating random recombination among homologs in different S. spontaneum accessions. The allele-defined Saccharum genome offers new knowledge and resources to accelerate sugarcane improvement.
09 BIOMASS FUELS↗
Many-body chaos and energy dynamics in holography
Recent developments have indicated that in addition to out-of-time ordered correlation functions (OTOCs), quantum chaos also has a sharp manifestation in the thermal energy density two-point functions, at least for maximally chaotic systems. The manifestation, referred to as pole-skipping, concerns the analytic behaviour of energy density two-point functions around a special point ω = iλ, k = iλ/v B in the complex frequency and momentum plane. Here λ and v B are the Lyapunov exponent and butterfly velocity characterising quantum chaos. In this paper we provide an argument that the phenomenon of pole-skipping is universal for general finite temperature systems dual to Einstein gravity coupled to matter. In doing so we uncover a surprising universal feature of the linearised Einstein equations around a static black hole geometry. We also study analytically a holographic axion model where all of the features of our general argument as well as the pole-skipping phenomenon can be verified in detail.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗