The variation of intestinal autochthonous bacteria in cultured tiger pufferfish Takifugu rubripes

Intestinal autochthonous bacteria play important roles in the maintenance of the physiological homeostasis of animals, especially contributing to the host immune system. In the present study, the variation of autochthonous bacterial community in the intestinal tract of 2-7 months-old tiger pufferfish Takifugu rubripes and bacterial communities in the seawater of recirculating aquaculture system (RAS) and the following offshore sea cage aquaculture system (OSCS) were analyzed during the aquaculture period from May to October 2021. Proteobacteria was found to be the most dominant phyla in both intestinal and seawater bacterial communities, which accounted for 68.82% and 65.65% of the total bacterial abundance, respectively. Arcobacter was the most core bacterial taxon in the intestinal bacterial community, with the most dominant abundance (42.89%) at the genus level and dominant positions in co-occurrence relationships with other bacterial taxa (node-betweenness value of 150). Enterococcaceae was specifically enriched in the intestinal bacterial community of pufferfishes from RAS, while Vibrionaceae was enriched in the intestinal bacterial community from OSCS. The F-values of beta diversity analysis between intestinal and seawater bacterial communities generally increased from May (6.69) to October (32.32), indicating the increasing differences between the intestinal and seawater bacterial communities along with the aquaculture process. Four bacterial taxa of Weissella sp., Akkermansia muciniphila, Dietzia sp. and Psychrobacter pacificensis had significant correlations with immune response parameters, and they were suggested to be the indicators for immune status and pathological process of pufferfish. The knowledge about the specific core bacteria, potentially pathogenic bacteria and the change of bacterial community in the intestinal tract of cultured pufferfish is of great scientific significance and will contribute to the understanding of intestinal bacterial homeostasis and biosecurity practice in pufferfish aquaculture

Imaging Sodium Dendrite Growth in All‐Solid‐State Sodium Batteries using 23Na T2‐weighted MRI

Two‐dimensional, Knight‐shifted, T2‐contrasted 23Na magnetic resonance imaging of an all‐solid‐state cell with Na electrode and a ceramic electrolyte is employed to directly observe Na microstructural growth. A spalling dendritic morphology is observed and confirmed by more conventional post‐mortem analysis; X‐ray tomography and scanning electron microscopy. A significantly greater 23Na T2 for the dendritic growth, compared with the bulk metal electrode, is attributed to increased sodium ion mobility in the dendrite. 23Na T2‐contrast MRI of metallic sodium offers a clear, routine method for observing and isolating microstructural growths and can supplement the current suite of techniques utilised to analyse dendritic growth in all‐solid‐state cells

Influence of contouring the lithium metal/solid electrolyte interface on the critical current for dendrites

Contouring or structuring of the lithium/ceramic electrolyte interface and therefore increasing its surface area has been considered as a possible strategy to increase the charging current in solid-state batteries without lithium dendrite formation and short-circuit. By coupling together lithium deposition kinetics and the me chanics of lithium creep within calculations of the current distribution at the interface, and leveraging a model for lithium dendrite growth, we show that efforts to avoid dendrites on charging by increasing the interfacial surface area come with significant limitations associated with the topography of rough surfaces. These limitations are sufficiently severe such that it is very unlikely contouring could increase charging currents while avoiding dendrites and short-circuit to the levels required. For example, we show a sinusoidal surface topography can only raise the charging current before dendrites occur by approx. 50% over a flat interface

Influence of contouring the lithium metal/solid electrolyte interface on the critical current for dendrites

Contouring or structuring of the lithium/ceramic electrolyte interface and therefore increasing its surface area has been considered as a possible strategy to increase the charging current in solid-state batteries without lithium dendrite formation and short-circuit. By coupling together lithium deposition kinetics and the me chanics of lithium creep within calculations of the current distribution at the interface, and leveraging a model for lithium dendrite growth, we show that efforts to avoid dendrites on charging by increasing the interfacial surface area come with significant limitations associated with the topography of rough surfaces. These limitations are sufficiently severe such that it is very unlikely contouring could increase charging currents while avoiding dendrites and short-circuit to the levels required. For example, we show a sinusoidal surface topography can only raise the charging current before dendrites occur by approx. 50% over a flat interface

Integrated optical vortex beam receivers

A simple and ultra-compact integrated optical vortex beam receiver device is presented. The device is based on the coupling between the optical vortex modes and whispering gallery modes in a micro-ring resonator via embedded angular gratings, which provides the selective reception of optical vortex modes with definitive total angular momentum (summation of spin and orbital angular momentum) through the phase matching condition in the coupling process. Experimental characterization confirms the correct detection of the total angular momentum carried by the vortex beams incident on the device. In addition, photonic spin-controlled unidirectional excitation of whispering-gallery modes in the ring receiver is also observed, and utilized to differentiate between left- and right-circular polarizations and therefore unambiguously identify the orbital angular momentum of incident light. Such characteristics provide an effective mode-selective receiver for the eigen-modes in orbital angular momentum fiber transmission where the circularly polarized OAM modes can be used as data communications channels in multiplexed communications or as photonic states in quantum information applications

Decoupling, quantifying, and restoring aging-induced Zn-anode losses in rechargeable aqueous zinc batteries

The search for batteries beyond Li-ion that offer better performance, reliability, safety, and/or affordability has led researchers to explore a diverse array of candidates. The advantages of Zn-ion batteries reside in zinc’s relatively low reactivity, raising the prospect of a rechargeable battery with a simple aqueous electrolyte and a cheaper, safer option to the organic electrolytes that must be paired with reactive lithium. However, water still reacts with the zinc in corrosion reactions. These consume zinc, lowering the battery’s capacity, and generate gas that accumulates in the sealed cell. We diagnose the contribution of corrosion to performance decay in zinc batteries and reveal the critical role of gas accumulation in deactivating large sections of electrode, which cripples cell performance. Fortunately, electrodes can be reactivated by removal of the gas, demonstrating the importance of designing future cells that either prevent gas formation or facilitate its safe release

Revealing the role of fluoride‐rich battery electrode interphases by operando transmission electron microscopy

The solid electrolyte interphase (SEI), a complex layer that forms over the surface of electrodes exposed to battery electrolyte, has a central influence on the structural evolution of the electrode during battery operation. For lithium metallic anodes, tailoring this SEI is regarded as one of the most effective avenues for ensuring consistent cycling behavior, and thus practical efficiencies. While fluoride-rich interphases in particular seem beneficial, how they alter the structural dynamics of lithium plating and stripping to promote efficiency remains only partly understood. Here, operando liquid-cell transmission electron microscopy is used to investigate the nanoscale structural evolution of lithium electrodeposition and dissolution at the electrode surface across fluoride-poor and fluoride-rich interphases. The in situ imaging of lithium cycling reveals that a fluoride-rich SEI yields a denser Li structure that is particularly amenable to uniform stripping, thus suppressing lithium detachment and isolation. By combination with quantitative composition analysis via mass spectrometry, it is identified that the fluoride-rich SEI suppresses overall lithium loss through drastically reducing the quantity of dead Li formation and preventing electrolyte decomposition. These findings highlight the importance of appropriately tailoring the SEI for facilitating consistent and uniform lithium dissolution, and its potent role in governing the plated lithium's structure

The role of an elastic interphase in suppressing gas evolution and promoting uniform electroplating in sodium metal anodes †

Ether solvent based electrolytes exhibit excellent performance with sodium battery anodes, outperforming the carbonate electrolytes that are routinely used with the analogous lithium-ion battery. Uncovering the mechanisms that facilitate this high performance for ether electrolytes, and conversely diagnosing the causes of the poor cycling with carbonate electrolytes, is crucial for informing the design of optimized electrolytes that promote fully reversible sodium cycling. An important contributor to the performance difference has been suggested to be the enhanced elasticity of the ether-derived solid–electrolyte interphase (SEI) layer, however experimental demonstration of exactly how this translates to improving the microscopic dynamics of a cycled anode remain less explored. Here, we reveal how this more elastic SEI prevents gas evolution at the interface of the metal anode by employing operando electrochemical transmission electron microscopy (TEM) to image the cycled electrode–electrolyte interface in real time. The high spatial resolution of TEM imaging reveals the rapid formation of gas bubbles at the interface during sodium electrostripping in carbonate electrolyte, a phenomenon not observed for the higher performance ether electrolyte, which impedes complete Na stripping and causes the SEI to delaminate from the electrode. This non-conformal and inflexible SEI must thus continuously reform, leading to increased Na loss to SEI formation, as supported by mass spectrometry measurements. The more elastic ether interphase is better able to maintain conformality with the electrode, preventing gas formation and facilitating flat electroplating. Our work shows why an elastic and flexible interphase is important for achieving high performance sodium anodes

Achieving ultra‐high rate planar and dendrite‐free zinc electroplating for aqueous zinc battery anodes

Despite being one of the most promising candidates for grid-level energy storage, practical aqueous zinc batteries are limited by dendrite formation, which leads to significantly compromised safety and cycling performance. In this study, by using single-crystal Zn-metal anodes, reversible electrodeposition of planar Zn with a high capacity of 8 mAh cm−2 can be achieved at an unprecedentedly high current density of 200 mA cm−2. This dendrite-free electrode is well maintained even after prolonged cycling (>1200 cycles at 50 mA cm−2). Such excellent electrochemical performance is due to single-crystal Zn suppressing the major sources of defect generation during electroplating and heavily favoring planar deposition morphologies. As so few defect sites form, including those that would normally be found along grain boundaries or to accommodate lattice mismatch, there is little opportunity for dendritic structures to nucleate, even under extreme plating rates. This scarcity of defects is in part due to perfect atomic-stitching between merging Zn islands, ensuring no defective shallow-angle grain boundaries are formed and thus removing a significant source of non-planar Zn nucleation. It is demonstrated that an ideal high-rate Zn anode should offer perfect lattice matching as this facilitates planar epitaxial Zn growth and minimizes the formation of any defective regions

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data