Electrochemical-repaired porous graphene membranes for precise ion-ion separation.

The preparation of atom-thick porous lattice hosting Å-scale pores is attractive to achieve a large ion-ion selectivity in combination with a large ion flux. Graphene film is an ideal selective layer for this if high-precision pores can be incorporated, however, it is challenging to avoid larger non-selective pores at the tail-end of the pore size distribution which reduces ion-ion selectivity. Herein, we develop a strategy to overcome this challenge using an electrochemical repair strategy that successfully masks larger pores in large-area graphene. 10-nm-thick electropolymerized conjugated microporous polymer (CMP) layer is successfully deposited on graphene, thanks to a strong π-π interaction in these two materials. While the CMP layer itself is not selective, it effectively masks graphene pores, leading to a large Li+/Mg2+ selectivity from zero-dimensional pores reaching 300 with a high Li+ ion permeation rate surpassing the performance of reported materials for ion-ion separation. Overall, this scalable repair strategy enables the fabrication of monolayer graphene membranes with customizable pore sizes, limiting the contribution of nonselective pores, and offering graphene membranes a versatile platform for a broad spectrum of challenging separations.

Marine Fish Oil Replacement with Lard or Basa Fish (Pangasius bocourti) Offal Oil in the Diet of Tiger Puffer (Takifugu rubripes): Effects on Growth Performance, Body Composition, and Flesh Quality.

Lard (LD) and Basa fish offal oil (BFO) have similar fatty acid profiles, both containing high contents of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA). The present study aimed to investigate the efficacy of partial or complete replacement of marine fish oil (MFO, herring oil) by LD or BFO in the diets of tiger puffer. The control diet contained 49.1% crude protein and 9.28% crude lipid content including 6% added MFO. In other diets, 1/3, 2/3, and 3/3 of the added MFO was replaced by LD or BFO, respectively. Each diet was fed to triplicate tanks of juvenile fish (initial body weight, 13.88 g). A 46-day feeding trial was conducted in a flow-through seawater system. Each diet was fed to triplicate 200-L rectangular polyethylene tanks, each of which was stocked with 30 fish. Fish were fed to satiation three times a day. The complete replacement of added MFO (replacing 65% of the total crude lipid) had no adverse effects on fish growth performance in terms of survival (>94%), weight gain (360-398%), feed intake (2.37-3.04%), feed conversion ratio (0.84-1.02), and somatic indices. The dietary LD or BFO supplementation also had marginal effects on fish body proximate composition, biochemical parameters, muscle texture, and water-holding ability, as well as the hepatic expression of lipid metabolism-related genes. Partial (2/3) replacement of added MFO by LD or BFO did not significantly reduce the muscle n-3 LC-PUFA content, indicating the n-3 LC-PUFA sparing effects of SFA and MUFA in LD and BFO. In general, dietary LD or BFO reduced the peroxidation level and led to significant changes in the muscle volatile flavor compound profile, which were probably attributed to the change in fatty acid composition. The results of this study evidenced that LD and BFO are good potential lipid sources for tiger puffer feeds.

Unit-cell-thick zeolitic imidazolate framework films for membrane application.

Zeolitic imidazolate frameworks (ZIFs) are a subset of metal-organic frameworks with more than 200 characterized crystalline and amorphous networks made of divalent transition metal centres (for example, Zn2+ and Co2+) linked by imidazolate linkers. ZIF thin films have been intensively pursued, motivated by the desire to prepare membranes for selective gas and liquid separations. To achieve membranes with high throughput, as in ångström-scale biological channels with nanometre-scale path lengths, ZIF films with the minimum possible thickness-down to just one unit cell-are highly desired. However, the state-of-the-art methods yield membranes where ZIF films have thickness exceeding 50 nm. Here we report a crystallization method from ultradilute precursor mixtures, which exploits registry with the underlying crystalline substrate, yielding (within minutes) crystalline ZIF films with thickness down to that of a single structural building unit (2 nm). The film crystallized on graphene has a rigid aperture made of a six-membered zinc imidazolate coordination ring, enabling high-permselective H2 separation performance. The method reported here will probably accelerate the development of two-dimensional metal-organic framework films for efficient membrane separation.

Missing-linker Defects in Covalent Organic Framework Membranes for Efficient CO2 Separation.

Covalent organic framework (COF) membranes with tunable ordered channels and free organic groups hold great promise in molecular separations owing to the synergy of physical and chemical microenvironments. Herein, we develop a defect engineering strategy to fabricate COF membranes for efficient CO2 separation. Abundant amino groups are in situ generated on the COF nanosheets arising from the missing-linker defects during the reactive assembly of amine monomer and mixed aldehyde monomers. The COF nanosheets are assembled to fabricate COF membranes. Amino groups, as the CO2 facilitated transport carriers, along with ordered channels endow COF membrane with high CO2 permeances exceeding 300 GPU and excellent separation selectivity of 80 for CO2 /N2 , and 54 for CO2 /CH4 mixed gas under humidified state. Our defect engineering strategy offers a facile approach to generating free organic functional groups in COF membranes and other organic framework membranes for diverse chemical separations.

MOF-COF "Alloy" Membranes for Efficient Propylene/Propane Separation.

Molecular-sieving membranes from metal-organic frameworks (MOFs) are promising candidates for separating olefin/paraffin mixtures, a critical demand in sustainable chemical processes and a grand challenge in molecular separation. Currently, the inherent lattice flexibility of MOFs severely compromises their precise sieving ability. Here, a proof-of-concept of "alloy" membranes (AMs), which are fabricated by incorporating quaternary ammonium (QA)-functionalized covalent organic frameworks (COFs) into a zeolitic imidazolate framework-8 (ZIF-8) matrix is demonstrated. The Coulomb force between the COFs and the ZIF-8 restricts the linker rotation of the ZIF-8, generating a distinct alloying effect, by which the lattice rigidity of ZIF-8 can be conveniently tuned through varying the content of the COFs, similar to the flexible-to-rigid transition in aluminum alloy manufacturing. Such an alloying effect confers the AM's superior propylene/propane separation performance, with a propylene/propane separation factor surpassing 200 and a propylene permeance of 168 GPU. Hopefully, the AMs concept and the concomitant alloying effect can update the connotation of mixed matrix membranes and stimulate the re-envisioning about the design paradigm and development of advanced membranes for energy-efficient separations.

Oil-Water-Oil Triphase Synthesis of Ionic Covalent Organic Framework Nanosheets.

Ionic covalent organic framework nanosheets (iCOFNs) with long-range ordered and mono-dispersed ionic groups hold great potential in many advanced applications. Considering the inherent drawbacks of oil-water biphase method, herein, we explore an oil-water-oil triphase method based on phase engineering strategy for the bottom-up synthesis of iCOFNs. The middle water phase serves as a confined reaction region, and the two oil phases are reservoirs for storing and supplying monomers to the water phase. A large aqueous space and low monomer concentration lead to the anisotropic gradual growth of iCOFNs into few-layer thickness, large lateral size, and high crystallinity. Notably, the resulting three cationic and anionic iCOFNs exhibit ultra-high aspect ratios of up to 20,000. We further demonstrate their application potential by processing into ultrathin defect-free COF membranes for efficient biogas separation. Our triphase method may offer an alternative platform technology for the synthesis and innovative applications of iCOFNs.

Experimental Observation of Tensor Monopoles with a Superconducting Qudit.

Monopoles play a center role in gauge theories and topological matter. There are two fundamental types of monopoles in physics: vector monopoles and tensor monopoles. Examples of vector monopoles include the Dirac monopole in three dimensions and Yang monopole in five dimensions, which have been extensively studied and observed in condensed matter or artificial systems. However, tensor monopoles are less studied, and their observation has not been reported. Here we experimentally construct a tunable spin-1 Hamiltonian to generate a tensor monopole and then measure its unique features with superconducting quantum circuits. The energy structure of a 4D Weyl-like Hamiltonian with threefold degenerate points acting as tensor monopoles is imaged. Through quantum-metric measurements, we report the first experiment that measures the Dixmier-Douady invariant, the topological charge of the tensor monopole. Moreover, we observe topological phase transitions characterized by the topological Dixmier-Douady invariant, rather than the Chern numbers as used for conventional monopoles in odd-dimensional spaces.

Erratum: Experimental Measurement of the Quantum Metric Tensor and Related Topological Phase Transition with a Superconducting Qubit [Phys. Rev. Lett. 122, 210401 (2019)].

This corrects the article DOI: 10.1103/PhysRevLett.122.210401.

Experimental Measurement of the Quantum Metric Tensor and Related Topological Phase Transition with a Superconducting Qubit.

A Berry curvature is an imaginary component of the quantum geometric tensor (QGT) and is well studied in many branches of modern physics; however, the quantum metric as a real component of the QGT is less explored. Here, by using tunable superconducting circuits, we experimentally demonstrate two methods to directly measure the quantum metric tensor for characterizing the geometry and topology of underlying quantum states in parameter space. The first method is to probe the transition probability after a sudden quench, and the second one is to detect the excitation rate under weak periodic driving. Furthermore, based on quantum metric and Berry-curvature measurements, we explore a topological phase transition in a simulated time-reversal-symmetric system. The work opens up a unique approach to explore the topology of quantum states with the QGT.

[Modified reverse homodigital artery island flap for repair of fingertip defect].

OBJECTIVE: To investigate the operative method and clinical efficacy of repairing fingertip defect with modified reverse homodigital artery island flap. METHODS: From March 2000 to September 2006, 18 cases (24 fingers) of fingertip defect were treated, including 12 males and 6 females aged 18-53 years (mean 29 years). Defect was caused by crush injuries in 12 cases, by avulsion injury in 3 cases, by twist injury in 2 cases and by incised injury in 1 case. The time from injury to operation was 2-8 hours (mean 4 hours). The location were index fingers (3 fingers), middle fingers (4 fingers) and ring fingers (17 fingers). The defects of soft tissue were 1.9 cm x 1.7 cm to 2.4 cm x 1.9 cm in size, the reverse homodigital artery island flaps were from 2.0 cm x 1.5 cm to 2.5 cm x 2.0 cm in size. The donor site was repaired with dumped skin grafting (3 cases) and with skin grafting from medial area of planta pedis (15 cases). RESULTS: Skin flaps and skin grafting of all the 24 fingers survived after operation. All incisions and donor sites healed by first intention. Sixteen patients (22 fingers) were followed up for 1-5 years (mean 3.2 years).The appearance and function of the flaps were all satisfactory. Two-point discriminations of flaps ranged from 4.5 mm to 6.3 mm. According to the total active movement/total passive movement assessment criteria, the results were excellent in 20 fingers and good in 2 fingers; and the excellent and good rate was 100%. The circumference of donor site was 2.0-3.5 mm shorter than that of normal side. The two-point discriminations of donor site was 7.8-10.5 mm. CONCLUSION: Repairing defect of fingertip with modified reverse homodigital artery island flap can provide good texture and contour matching the recipient area, good function and little trauma at donor site.