An impact sensitivity assessment method of spacecraft based on virtual exterior wall

The impact sensitivity assessment of spacecraft is to obtain the probability of spacecraft encountering the OD/M(orbital debris or meteoroid),which is a prerequisite for survivability assessment of on-orbit spacecraft.An impact sensitivity assessment method of spacecraft based on virtual exterior wall was proposed to improve the computational efficiency.This method eliminates determination of the outermost surface elements of the spacecraft before generating the debris rays,which are assumed to originate from a non-concave virtual wall that completely wraps the spacecraft.The Dist Mesh method was adopted for the generating of the virtual wall to ensure its mesh quality.The influences of the sizes,mesh densities,shapes of the virtual wall on the efficiency and accuracy were considered to obtain the best combination of the size and mesh density of the wall and spacecraft.The results of this method were compared with those of S3DE(Survivability of Spacecraft in Space Debris Environment),BUMPER,MDPANTO,ESABASE2/Debris to verify the feasibility of the method.The PCHIP(Piecewise Cubic Hermite Interpolating Polynomial)was used to fit the size vs.flux relationship of the space debris to acquire the impact probability of OD/M with arbitrary size on the spacecraft.

Ultrathin 2D Metal–Organic Framework Nanosheets In situ Interpenetrated by Functional CNTs for Hybrid Energy Storage Device

The controllable construction of two-dimensional(2D)metal–organic framework(MOF)nanosheets with favorable electrochemical performances is greatly challenging for energy storage.Here,we design an in situ induced growth strategy to construct the ultrathin carboxylated carbon nanotubes(C-CNTs)interpenetrated nickel MOF(Ni-MOF/C-CNTs)nanosheets.The deliberate thickness and specific surface area of novel 2D hybrid nanosheets can be effectively tuned via finely controlling C-CNTs involvement.Due to the unique microstructure,the integrated 2D hybrid nanosheets are endowed with plentiful electroactive sites to promote the electrochemical performances greatly.The prepared Ni-MOF/C-CNTs nanosheets exhibit superior specific capacity of 680 C g^−1 at 1 A g^−1 and good capacity retention.The assembled hybrid device demonstrated the maximum energy density of 44.4 Wh kg^−1 at a power density of 440 W kg^−1.Our novel strategy to construct ultrathin 2D MOF with unique properties can be extended to synthesize various MOF-based functional materials for diverse applications.

Ratiometric delivery of doxorubicin and berberine by liposome enables superior therapeutic index than Doxil?

Although the appearance of Doxil alleviated the cardiotoxicity of DOX, the progression-free survival of patients was not prolonged compared with traditional medication regimens, and side effects such as hand-foot syndrome has occurred. In order to solve this dilemma, we have designed a novel co-delivery strategy to construct a co-loaded liposome of berberine(BER) and doxorubicin(DOX), which was called Lipo Be Do. The optimal synergistic ratio of the two drugs was screened by cell cytotoxicity experiments in vitro, and the optimal attenuation ratio was further determined by in vivo cardiac H&E staining pathological sections. The optimal combination treatment caused a robust increase in apoptotic cells of 4T1, as compared to drug alone treatment. The prepared co-loaded liposome, Lipo Be Do, had high encapsulation efficiency and good stability. The nanoliposome carrier controlled the biological fate of the drugs and maintained a pre-defined optimal ratio in vivo. The Lipo Be Do significantly inhibited tumor growth in 4T1 murine mammary carcinoma model compared with Doxil(P < 0.05), and completely overcame the myocardial rupture toxicity caused by Doxil in mice. Our co-loaded liposome delivery platform technology provided a new direction for the clinical treatment of triple-negative breast cancer and the safe application of DOX.

Genome-wide identification of functional enhancers and their potential roles in pig breeding

Background:The pig is an economically important livestock species and is a widely applied large animal model in medical research.Enhancers are critical regulatory elements that have fundamental functions in evolution,development and disease.Genome-wide quantification of functional enhancers in the pig is needed.Results:We performed self-transcribing active regulatory region sequencing(STARR-seq)in the porcine kidney epithelial PK15 and testicular ST cell lines,and reliably identified 2576 functional enhancers.Most of these enhancers were located in repetitive sequences and were enriched within silent and lowly expressed genes.Enhancers poorly overlapped with chromatin accessibility regions and were highly enriched in chromatin with the repressive histone modification H3K9me3,which is different from predicted pig enhancers detected using ChIP-seq for H3K27ac or/and H3K4me1 modified histones.This suggests that most pig enhancers identified with STARR-seq are endogenously repressed at the chromatin level and may function during cell type-specific development or at specific developmental stages.Additionally,the PPP3CA gene is associated with the loin muscle area trait and the QKI gene is associated with alkaline phosphatase activity that may be regulated by distal functional enhancers.Conclusions:In summary,we generated the first functional enhancer map in PK15 and ST cells for the pig genome and highlight its potential roles in pig breeding.

On-line Monitoring of Epoxy Resin Exposed to Acid Solution

In this study, a new on-line health monitoring technology for the determination of the penetration of environment solution into epoxy resin was pursued. A corrosion sensor including plastic optical fiber and pH indicator was fabricated. The color-change layer of this sensor appeared after immersion in sulfuric acid solution, which could be examined by using optical fiber and spectrophotometer. The results showed that the penetration of sulfuric acid was detected by adding bromophenol blue （BPB） in the corrosion sensor. This system could be applied to on-line health monitoring of chemical equipment structures.

A phase separation-fortified bi-specific adaptor for conditional tumor killing

A common approach in therapeutic protein development involves employing synthetic ligands with multivalency,enabling sophisticated control of signal transduction.Leveraging the emerging concept of liquid-liquid phase separation(LLPS)and its ability to organize cell surface receptors into functional compartments,we herein have designed modular ligands with phase-separation modalities to engineer programmable interreceptor communications and precise control of signal pathways,thus inducing the rapid,potent,and specific apoptosis of tumor cells.Despite their simplicity,these“triggers”,named phase-separated Tumor Killers(hereafter referred to as psTK),are sufficient to yield interreceptor clustering of death receptors(represented by DR5)and tumor-associated receptors,with notable features:LLPSmediated robust high-order organization,well-choreographed conditional activation,and broad-spectrum capacity to potently induce apoptosis in tumor cells.The development of novel therapeutic proteins with phase-separation modalities showcases the power of spatially reorganizing signal transduction.This approach facilitates the diversification of cell fate and holds promising potential for targeted therapies against challenging tumors.

Research advances in the function and anti-aging effects of nicotinamide mononucleotide

Aging and age-related ailments have emerged as critical challenges and great burdens within the global contemporary society.Addressing these concerns is an imperative task,with the aims of postponing the aging process and finding effective treatments for age-related degenerative diseases.Recent investigations have highlighted the significant roles of nicotinamide adenine dinucleotide(NAD+)in the realm of anti-aging.It has been empirically evidenced that supplementation with nicotinamide mononucleotide(NMN)can elevate NAD+levels in the body,thereby ameliorating certain age-related degenerative diseases.The principal anti-aging mechanisms of NMN essentially lie in its impact on cellular energy metabolism,inhibition of cell apoptosis,modulation of immune function,and preservation of genomic stability,which collectively contribute to the deferral of the aging process.This paper critically reviews and evaluates existing research on the anti-aging mechanisms of NMN,elucidates the inherent limitations of current research,and proposes novel avenues for anti-aging investigations.

Microgroove-structured liquid-like surface for liquid discrimination

Discriminating between different liquids using surfaces with special wettability holds significant implications for both fundamental research and practical applications.However,current differentiation surfaces still struggle with challenges such as complex microstructure design,a limited detection range,and poor stability.In this study,we present a new platform for droplet discrimination achieved through a combination of groove structures and a liquid-like polydimethylsiloxane(PDMS)brushes coating.The PDMS brushes coating exhibits excellent stability and low adhesion across a wide range of liquids with surface tensions ranging from 27.5 to 72.8 mN/m,while the groove structure provides distinct energy barriers for droplet sliding.Consequently,liquids with varying surface tensions can be effectively discriminated,as evidenced by the increased sliding angles(SAs)observed as liquids with lower surface tension moving across the groove.Furthermore,we utilized a three dimensional(3D)model of the droplet developed using Surface Evolver,and conducted energy variation calculations during droplet sliding across the groove to analyze the SA differences among liquids with different surface tensions.Additionally,we proposed two simple differentiation platforms that successfully demonstrated effective droplet discrimination.This work introduces a novel strategy for droplet discrimination,offering innovative ideas for the design of functional surfaces.These findings may potentially be applied in other fields involving droplet manipulation,such as droplet-based microchemical reactions and bio-detection.

Space debris environment engineering model 2019:Algorithms improvement and comparison with ORDEM 3.1 and MASTER-8

As an essential tool for realistic description of the current or future debris environment,the Space Debris Environment Engineering Model(SDEEM)has been developed to provide support for risk assessment of spacecraft.In contrast with SDEEM2015,SDEEM2019,the latest version,extends the orbital range from the Low Earth Orbit(LEO)to Geosynchronous Orbit(GEO)for the years 1958-2050.In this paper,improved modeling algorithms used by SDEEM2019 in propagating simulation,spatial density distribution,and spacecraft flux evaluation are presented.The debris fluxes of SDEEM2019 are compared with those of three typical models,i.e.,SDEEM2015,Orbital Debris Engineering Model 3.1(ORDEM 3.1),and Meteoroid and Space Debris Terrestrial Environment Reference(MASTER-8),in terms of two assessment modes.Three orbital cases,including the Geostationary Transfer Orbit(GTO),Sun-Synchronous Orbit(SSO)and International Space Station(ISS)orbit,are selected for the spacecraft assessment mode,and the LEO region is selected for the spatial density assessment mode.The analysis indicates that compared with previous algorithms,the variable step-size orbital propagating algorithm based on semi-major axis control is more precise,the spatial density algorithm based on the second zonal harmonic of the non-spherical Earth gravity(J_(2))is more applicable,and the result of the position-centered spacecraft flux algorithm is more convergent.The comparison shows that SDEEM2019 and MASTER-8 have consistent trends due to similar modeling processes,while the differences between SDEEM2019 and ORDEM 3.1 are mainly caused by different modeling approaches for uncatalogued debris.

Dual-responsive shape memory polymer arrays with smart and precise multiple-wetting controllability

Smart-controlled surface wettability from superhydrophilicity to superhydrophobicity has been extensively explored,and stimulus-responsive strategies have been widely accepted as a useful method to realize reversibility.However,achieving smart and precise wetting control remains challenging because most previous studies focused on stimulating single surface chemistry or microstructures.Herein,a dualstimulus-responsive strategy that can synergistically stimulate surface chemistry and microstructures is demonstrated on the pH-responsive molecule poly(2-(diisopropylamino)ethyl methacrylate(PDPAEMA)-modified temperature-triggered shape memory polymer(SMP)arrays.The responsive PDPAEMA and SMP can provide the surface with tunable surface chemistry and microstructures,respectively.Thus,the wetting of the surface between various states can be reversibly and precisely controlled from superhydrophilicity to superhydrophobicity with contact angle(CA)differences of less than 15° under the cooperative effect between the adjustable surface microstructure and chemistry.The surface is further utilized as a platform to create gradient wettings based on its excellent controllability.Therefore,this work presents a strategy for surface wetting control by combining tunable surface microstructures and chemistry.The prepared samples with a special wetting controllability can be applied to numerous fields,including adaptive liquid microlenses,accurate drug release,and selective catalysis.This work also proposes novel expectations in designing smart functional surfaces.

A shape memory porous sponge with tunability in both surface wettability and pore size for smart molecule release

Recently,smart superwetting porous materials have aroused much attention,and it is well known that tunable surface wettability and pore structure/size are extremely important for their functions.However,only one factor can be regulated on existing materials,which significantly restricts their controllability,functions,and applications.A new material was prepared by electrodepositing a layer of polypyrrole on a shape memory sponge,on which switchable superhydrophobicity/superhydrophilicity and adjustable pore size within the range of about 28 nm to 895μm can be observed.Through synergistically tuning the wettability and pore size,both ON/OFF water permeation and accurate flux can be obtained.Meanwhile,we also applied the sponge for molecule release,and diverse release manners with precise/smart controllability can be accomplished.This paper reports for the first time a smart material with controllability in both surface wetting and pore size,which provides a new strategy for the preparation of novel smart superwetting porous materials.

“Liquid diode”with“gating”based on shape memory sponge

Superwetting Janus membranes with unique ability in unidirectional liquid transportation,known as“liquid diode”,have attracted much attention.Recently,endowing the Janus membranes with smart controllability becomes a new research hotspot.However,related reports are still rare and limited in regulating surface wettability,which can hardly avoid some imperfections such as the necessary constant external stimuli and change of water solution.Herein,we advanced an unprecedented strategy to smartly control the liquid permeation on Janus membrane by regulating the pore structure of the material,and report a smart Janus sponge(SJS)that is constructed from a super-hydrophilic sponge(SHS)and a hydrophobic shape memory sponge(HSMS).The pore size and thickness of the HSMS can be reversibly changed as it is pressed/recovered based on the excellent shape memory effect.With the variation of the HSMS,the water permeation performance can be smartly controlled,which is embodied in that only when the HSMS is in the pressed state,SJS acts as a“liquid diode”,otherwise it can prevent liquid from penetrating on either side.Finally,based on the smart controllability of the SJS,we simulated the scene of drug administration and demonstrated its potential application in the field of wound dressing.This work firstly reports a shape memory Janus membrane and provides a new way to control the liquid permeation,which can successfully avoid those shortcomings existing in current wetting-responsive Janus membranes.Given its excellent controllability,we believe it has potential applications in intelligent manipulation of liquid.

A photocatalytic radical relay reaction of 2-methylthiolated phenylalkynones and potassium metabisulfite

The generation of methylsufonyl-containing thioflavones through a radical relay reaction of methylthiolated phenylalkynones and potassium metabisulfite in the presence of a catalytic amount of sodium methylsulfinate as an initiator under photoinduced conditions is developed.This photocatalytic reaction proceeds smoothly with good functional group tolerance under visible light irradiation.Preliminary mechanistic investigations indicate that this reaction occurs through a radical relay pathway.