天然生物大分子稳定高内相Pickering乳液及其在食品中的应用

近几年,高内相Pickering乳液(high internal phase Pickering emulsions,HIPPEs)因其独特的组织特性受到越来越多的关注,在食品领域的应用前景非常可观。天然生物大分子作为生物体内的活性成分,具有良好的生物相容性、可降解性、无毒或低毒性等特性,是优异的HIPPEs稳定剂。本文简述了天然生物大分子稳定HIPPEs的潜力,以及基于生物大分子稳定的HIPPEs在抑制脂质的氧化、作为反式脂肪酸的替代品、封装和递送营养物质、食品3D打印以及包埋益生菌方面的应用研究进展,以期为基于天然生物大分子稳定的HIPPEs在食品中的应用提供参考和借鉴。

Developing high-efficiency base editors by combining optimized synergistic core components with new types of nuclear localization signal peptide

The clustered regularly interspaced short palindromic repeats(CRISPR)–CRISPR-associated protein(Cas) system has been widely used for genome editing. In this system, the cytosine base editor(CBE) and adenine base editor(ABE) allow generating precise and irreversible base mutations in a programmable manner and have been used in many different types of cells and organisms. However, their applications are limited by low editing efficiency at certain genomic target sites or at specific target cytosine(C) or adenine(A) residues. Using a strategy of combining optimized synergistic core components, we developed a new multiplex super-assembled ABE(sABE) in rice that showed higher base-editing efficiency than previously developed ABEs. We also designed a new type of nuclear localization signal(NLS) comprising a FLAG epitope tag with four copies of a codon-optimized NLS(F4NLS^(r2)) to generate another ABE named F4NLS-sABE. This new NLS increased editing efficiency or edited additional A at several target sites. A new multiplex super-assembled CBE(sCBE) and F4NLS^(r2) involved F4NLS-sCBE were also created using the same strategy. F4NLS-sCBE was proven to be much more efficient than sCBE in rice. These optimized base editors will serve as powerful genome-editing tools for basic research or molecular breeding in rice and will provide a reference for the development of superior editing tools for other plants or animals.

可再分散甲壳素纳米纤维的制备及其在稳定Pickering乳液中的应用

利用氯乙酸对部分脱乙酰化甲壳素进行羧甲基化处理,获得同时带有氨基和羧基的甲壳素纳米纤维(chitin nanofibers,ChNFs),所得ChNFs经干燥除去分散介质后可再次分散在超纯水中,再分散前后ChNFs的长径比变化不大。ChNFs还可以有效稳定Pickering乳液,流变学结果显示乳液类型为O/W型乳液,当ChNFs质量分数大于0.5%时,所稳定的乳液(油相质量分数为10%)在90 d贮藏期内均表现出良好的稳定性。此外,ChNFs能在较大pH值范围(3~11)内稳定乳液。总体来看,ChNFs可作为一种新型Pickering稳定剂应用于食品生物领域保护和递送对pH值敏感的活性物质。

Utility of Goal Attainment Scaling(GAS)in evaluating a multicomponent exercise programme for community-dwelling pre-frail older adults

Objectives This study aimed to investigate the effectiveness of Goal Attainment Scaling(GAS)in assessing an intervention for pre-frail senior citizens.Additionally,the study aimed to explain how the GAS goals were established based on the International Classification of Functioning,Disability and Health(ICF)categories,including body function,activity and participation and environmental factors.Methods In this study,220 pre-frail older adults were randomly selected to participate in a controlled trial.The intervention group engaged in multicomponent exercise three times a week,once at a community health service location and twice at home.The control group received advice on physical activity but did not have supervised exercise.Participants in both groups selected individualised GAS goals from 23 goals developed based on ICF by focus group discussion.The study used generalised estimating equations to analyse the differences between the groups.Results The study included 144 participants,72 in the exercise group and 72 in the control group.The top three individualised goals for all participants were vestibular functions(53.5%),pain management(43.1%)and lifting and carrying objects(31.9%).Both groups saw a significant increase in GAS scores at week 8 and week 24 of the intervention(p<0.05),but the exercise group showed a more significant improvement(p<0.05).The participants living alone were associated with lower postintervention improvements in the GAS scores.In contrast,the participants who were using a smartphone were likely to get higher postintervention improvements in the GAS scores.Conclusions GAS can be a valuable tool for setting and evaluating individualised and meaningful goals in body functions,activity and participation and environmental factors.The multicomponent exercise interventions can help pre-frail older adults achieve their expected goals as measured by the GAS.

载人深空探索中空间辐射防护技术的研究进展

空间辐射防护是载人深空探索任务中降低航天员的空间辐射损伤和致病风险,确保航天员健康与安全的重要保障措施.然而,由于空间辐射环境的独特性与复杂性,目前的辐射防护技术面临着一系列的问题与挑战.本文在分析载人深空探索任务中空间辐射环境特点的基础上,系统综述了空间辐射防护技术中物理防护和生物医学防护技术的研究进展,提出了深空探索任务中空间辐射防护研究涉及的关键技术问题以及后续开展深入研究的一些设想,可为载人深空探索任务的实施提供参考与借鉴.

Discriminated sgRNAs-Based SurroGate System Greatly Enhances the Screening Efficiency of Plant Base-Edited Cells

The development of CRISPR/Cas9-mediated base editing has made genomic modification more efficient. However, selection of genetically modified cells from millions of treated cells, especially plant cells, is still challenging. In this study, an efficient surrogate reporter system based on a defective hygromycin resistance gene was established in rice to enrich base-edited cells. After step-by-step optimization, the Discriminated sgRNAs-based SurroGate system (DisSUGs) was established by artificially differentiating the editing abilities of a wild-type single guide RNA (sgRNA) targeting the surrogate reporter gene and an enhanced sgRNA targeting endogenous sites. The DisSUGs enhanced the efficiency of screening base-edited cells by 3- to 5-fold for a PmCDA1-based cytosine-to-tyrosine base editor (PCBE), and 2.5- to 6.5-fold for an adenine base editor (ABE) at endogenous targets. These targets showed editing efficiencies of <25% in the conventional systems. The DisSUGs greatly enhanced the frequency of homozygous substitutions and expanded the activity window slightly for both a PCBE and an ABE. Analyses of the total number of single-nucleotide variants from whole-genome sequencing revealed that, compared with the no-enrichment PCBE strategy, the DisSUGs did not alter the frequency of genome-wide sgRNA-independent off-target mutations, but slightly increased the frequency of target-dependent off-target mutations. Collectively, the DisSUGs developed in this study greatly enhances the efficiency of screening plant base-edited cells and will be a useful system in future applications.

Three-dimensionally macroporous graphene-supported Fe_3O_4 composite as anode material for Li-ion batteries with long cycling life and ultrahigh rate capability

Fe3O4 is an attractive conversion reactionbased anode material with high theoretical capacity(928 mA h g-1).However,the poor cycling and rate performance hinder its applications in Li-ion batteries.In this work,we report an effective strategy to synthesize threedimensionally macroporous graphene-supported Fe3O4hybrid composite.Benefiting from advantage of the special structure,the hybrid composite exhibits excellent Li+ storage performance,delivering a high reversible capacity of980 mA h g-1at the current density of 4 A g-1even after470 cycles and ultrahigh rate capability(293 mA h g-1even at current density of 20 A g-1).

Wetting behaviors of molten melt drops on polycrystalline Al2O3 substrates in high magnetic fields

We measured the contact angles of Al and Sn drops on polycrystalline Al2O3 substrates in various high magnetic fields at different temperatures.The contact angles of both Al and Sn drops on the Al2O3 substrates decreased under high magnetic fields.These decreases strongly depend on the temperature,magnetic flux density,magnetic properties of the metal drops,and the reactivity of the metal drops with Al2O3.Our results reveal that the wetting behavior of molten metal drops on ceramics can be modified by a high magnetic field.

Prussian blue analogues-derived nitrogen-doped carboncoated FeO/CoO hollow nanocages as a high-performance anode material for Li storage

The design of electrode materials with specific structures is considered a promising approach for improving the performance of lithium-ion batteries(LIBs).In this paper,FeO/CoO hollow nanocages coated with a N-doped carbon layer(FCO@NC)was prepared using Fe-Co-based Prussian blue analogs(PBA)as a precursor.During the synthesis,dopamine was the carbon and nitrogen source.The reducing atmosphere was assured via NH_3/Ar,which regulated the vacancies in the structure of FCO@NC as well as increased its conductivity.When used as anode materials for LIBs,the FCO@NC nanocages deliver a high reversible capacity of 774.89 mAh·g^(-1)at 0.3 A·g^(-1)after200 cycles with a capacity retention rate of 80.4%and426.76 mAh·g^(-1)after 500 cycles at a high current density of 1 A·g^(-1).It is demonstrated that the hollow nanocage structure can effectively enhance the cycle stability,and the heat treatment in NH_(3)/Ar atmosphere contributes to the oxygen vacancy content of the electrode materials,further facilitating its conductivity and electrochemical performance.

Utilization of electroless plating to prepare Cu-coated cotton cloth electrode for flexible Li-ion batteries

Flexible,lightweight and high conductivity substrates are required for the development of next-generation flexible Li-ion batteries(LIBs).In addition,the interfacial strength between the active material and flexible substrate should be optimized for high-performance LIBs.Herein,cotton cloth(CC)is employed as a flexible substrate,and electroless plating is utilized to deposit a layer of Cu nanoparticles,which enhances the conductivity of CC and acts as a precursor for the active material,i.e.,CuO.The results reveal that the in situ etching and subsequent heat treatment converted Cu film into CuO nanowires on CC substrate.Moreover,carbon nano tubes(CNTs)are introduced to enhance the connectivity of CuO nano wires.Consequently,the CuO/CNT/CC electrode rendered a high areal capacity of>700μAh-cm^(-2)after100 charge/discharge cycles as well as excellent rate capability.The current work presents a novel route to develop desirable substrates for next-generation flexible Li-ion batteries.

Fe3O4-nanoparticle-decorated TiO2 nanofiber hierarchical heterostructures with improved lithium-ion battery performance over wide temperature range

A facile strategy was designed for the fabrication of Fe3O4-nanoparticle- decorated TiO2 nanofiber hierarchical heterostructures （FTHs） by combining the versatility of the electrospinning technique and the hydrothermal growth method. The hierarchical architecture of Fe3O4 nanoparticles decorated on TiO2 nanofibers enables the successful integration of the binary composite into batteries to address structural stability and low capacity. In the resulting unique architecture of FTHs, the 1D heterostructures relieve the strain caused by severe volume changes of Fe3O4 during numerous charge-discharge cycles, and thus suppress the degradation of the electrode material. As a result, FTHs show excellent performance including higher reversible capacity, excellent cycle life, and good rate performance over a wide temperature range owing to the synergistic effect of the binary composition of TiO2 and Fe304 and the unique features of the hierarchical nanofibers.

The accelerating nanoscale Kirkendall effect in Co films–native oxide Si(100)system induced by high magnetic fields

The morphology evolution and magnetic properties of Co films–native oxide Si(100)were investigated at 873,973,and 1073 K in a high magnetic field of 11.5 T.Formation of Kirkendall voids in the Co films was found to cause morphology evolution due to the difference in diffusion flux of Co and Si atoms through the native oxide layer.The high magnetic fields had considerable effect on the morphology evolution by accelerating nanoscale Kirkendall effect.The diffusion mechanism in the presence of high magnetic fields was given to explain the increase of diffusion coefficient.The morphology evolution of Co films on native oxide Si(100)under high magnetic fields during annealing resulted in the magnetic properties variation.

Preparation of a Pt-Ni_(2)P/NF catalyst for highly efficient hydrogen evolution using a magnetic field to promote Ni-Pt galvanic replacement

The noble metal Pt is an ideal catalyst for promoting the hydrogen evolution reaction(HER)during the electrolysis of water.However,Pt is also expensive and suffers from low utilization rates.In this work,a Pt-Ni_(2)P/NF nanorod catalyst with a low Pt loading was synthesized under different magnetic fields,and it was found that the application of a magnetic field can increase the rate of the galvanic replacement reaction.When the magnetic field strength increases from 0 to 600 mT,the chemical reaction rate increases gradually,and the utilization rate of Pt increased by 2.3 times under 600 mT.The mechanism of the magnetic field-induced magnetohydrodynamic(MHD)effect on the galvanic replacement reaction was revealed.In a 1 M KOH solution and at a current density of 10 mA cm^(-2),the overpotential of Pt-Ni_(2)P/NF prepared by applying a 600 mT magnetic field was as low as 15 mV and the Tafel slope was 37 mV dec^(-1),compared with values of 82 mV and 70 mV dec^(-1) for a specimen prepared without a magnetic field.Additionally,at an overpotential of 90 mV,the mass-based Pt activity of the former material was 12 times greater while its turnover frequency was 19 times greater.This work provides theoretical and technical knowledge expected to assist in the controllable preparation of materials in magnetic fields and the efficient utilization of metallic resources.

A thermoelectric generator and water-cooling assisted high conversion efficiency polycrystalline silicon photovoltaic system

Solar energy has been increasing its share in the global energy structure. However, the thermal radiation brought by sunlight will attenuate the efficiency of solar cells. To reduce the temperature of the photovoltaic (PV) cell and improve the utilization efficiency of solar energy, a hybrid system composed of the PV cell, a thermoelectric generator (TEG), and a water-cooled plate (WCP) was manufactured. The WCP cannot only cool the PV cell, but also effectively generate additional electric energy with the TEG using the waste heat of the PV cell. The changes in the efficiency and power density of the hybrid system were obtained by real time monitoring. The thermal and electrical tests were performed at different irradiations and the same experiment temperature of 22°C. At a light intensity of 1000 W/m2, the steady-state temperature of the PV cell decreases from 86.8°C to 54.1°C, and the overall efficiency increases from 15.6% to 21.1%. At a light intensity of 800 W/m2, the steady-state temperature of the PV cell decreases from 70°C to 45.8°C, and the overall efficiency increases from 9.28% to 12.59%. At a light intensity of 400 W/m2, the steady-state temperature of the PV cell decreases from 38.5°C to 31.5°C, and the overall efficiency is approximately 3.8%, basically remain unchanged.

Effect of a high-gradient magnetic field on grain refinement of a hypoeutectic Mn-Sb alloy during directional solidification

The obvious grain refinement of the primary MnSb phase has been observed in the Mn-89.7 wt%Sb alloy directionally solidified under a high-gradient magnetic field.With the application of a high-gradient magnetic field,the morphology of the primary MnSb phase transformed from developed dendritic-like to equiaxed-like,and the grain size decreased by approximately 93%.Refinement of the primary MnSb phase can be attributed to the constituent supercooling in front of the solidification interface,which promoted nucleation of the primary MnSb phase.The constituent supercooling can be linked to the enrichment of the Mn solute induced by the magnetic force and the Lorentz force that drove Mn solute migration and suppressed convection.