Highly tough slide-crosslinked gel polymer electrolyte for stable lithium metal batteries.

Gel polymer electrolytes (GPEs) hold great promise for the practical application of lithium metal batteries. However, conventional GPEs hardly resists lithium dendrites growth and maintains long-term cycling stability of the battery due to its poor mechanical performance. Inspired by the slide-ring structure of polyrotaxanes (PRs), herein we developed a dynamic slide-crosslinked gel polymer electrolyte (SCGPE) with extraordinary stretchability of 970.93% and mechanical strength of 1.15 MPa, which is helpful to buffer the volume change of electrodes and maintain mechanical integrity of the battery structure during cycling. Notably, the PRs structures can provide fast ion transport channels to obtain high ionic conductivity of 1.73×10-3 S cm-1 at 30°C. Additionally, the strong polar groups in SCGPE restrict the free movement of anions to achieve high lithium-ion transference number of 0.71, which is favorable to enhance Li+ transport dynamics and induce uniform Li+ deposition. Benefiting from these features, the constructed Li|SCGPE-3|LFP cells exhibit ultra-long and stable cycle life over 1000 cycles and high-capacity retention (89.6% after 1000 cycles). Even at a high rate of 16C, the cells deliver a high capacity of 79.2 mAh g-1. The slide-crosslinking strategy in this work provides a new perspective on the design of advanced GPEs for LMBs.

Extracellular vesicles from retinal pigment epithelial cells expressing R345W-Fibulin-3 induce epithelial-mesenchymal transition in recipient cells.

We have shown previously that expression of R345W-Fibulin-3 induces epithelial-mesenchymal transition (EMT) in retinal pigment epithelial (RPE) cells. The purpose of the current study was to determine if extracellular vesicles (EVs) derived from RPE cells expressing R345W-Fibulin-3 mutation are sufficient to induce EMT in recipient cells. ARPE-19 cells were infected with luciferase-tagged wild-type (WT)- Fibulin-3 or luciferase-tagged R345W-Fibulin-3 (R345W) using lentiviruses. EVs were isolated from the media by ultracentrifugation or density gradient ultracentrifugation. Transmission electron microscopy and cryogenic electron microscopy were performed to study the morphology of the EVs. The size distribution of EVs were determined by nanoparticle tracking analysis (NTA). EV cargo was analysed using LC-MS/MS based proteomics. EV-associated transforming growth factor beta 1 (TGFß1) protein was measured by enzyme-linked immunosorbent assay. The capacity of EVs to stimulate RPE migration was evaluated by treating recipient cells with WT- or R345W-EVs. The role of EV-bound TGFß was determined by pre-incubation of EVs with a pan-TGFß blocking antibody or IgG control. EM imaging revealed spherical vesicles with two subpopulations of EVs: a group with diameters around 30 nm and a group with diameters over 100 nm, confirmed by NTA analysis. Pathway analysis revealed that members of the sonic hedgehog pathway were less abundant in R345W- EVs, while EMT drivers were enriched. Additionally, R345W-EVs had higher concentrations of TGFß1 compared to control. Critically, treatment with R345W-EVs was sufficient to increase EMT marker expression, as well as cell migration in recipient cells. This EV-increased cell migration was significantly inhibited by pre-incubation of EVs with pan-TGFß-neutralising antibody. In conclusion, the expression of R345W-Fibulin-3 alters the size and cargo of EVs, which are sufficient to enhance the rate of cell migration in a TGFß dependent manner. These results suggest that EV-bound TGFß plays a critical role in the induction of EMT in RPE cells.

Myxobolus xiushanensis n. sp. (Myxozoa: Myxobolidae) infecting the gill arches of Yellowhead Catfish Tachysurus fulvidraco from China.

OBJECTIVE: Myxosporidiosis of bagrid fishes has been a focus of aquaculture research in recent years. The purpose of this study is to characterize a novel myxobolid, named Myxobolus xiushanensis n. sp., infecting Yellowhead Catfish Tachysurus fulvidraco in China. METHODS: We used molecular biology, morphology, phylogeny, and histopathology in the present study. RESULT: Mature myxospores were circular to ellipsoidal in valve view, measuring 12.2 ± 0.4 µm (mean ± SD; range = 11.2-13.2 µm) in length and 10.6 ± 0.4 µm (9.5-11.1 µm) in width. Two oval polar capsules were equal in width (3.4 ± 0.2 µm; 3.0-3.8 µm) but slightly unequal in length: 5.6 ± 0.3 µm (5.3-6.1 µm) and 4.7 ± 0.2 µm (4.4-5.5 µm). The polar capsule was packed with five to seven spirals of polar tubules. Histopathological investigation demonstrated that the plasmodium under the cuticular layer of the gill arch only induced a local inflammatory response and did not cause serious damage to the gill arch's internal structure. The two small subunit (SSU) ribosomal DNA sequences of M. xiushanensis n. sp. showed 100% similarity and uniqueness, and the highest similarity with other myxosporean sequences in GenBank was 90.27% (query coverage = 94%). The secondary structures of the SSU ribosomal RNA revealed that the present species was distinctly different from related species in regions V4 and V7. Phylogenetic analysis showed that M. xiushanensis n. sp. clustered independently within a branch. CONCLUSION: These results enrich our understanding of the biodiversity of myxobolids infecting bagrid fishes and provide fundamental data for the diagnosis of myxosporidiosis.

The description of Myxobolus meijiangensis n. sp. (Myxozoa: Myxobolidae) and its pathogenicity to the gills of goldfish.

Myxobolus Bütschli, 1882 is the most speciose myxozoan genus, although some species have only been described according to the morphological characteristics of spores. In the present study, a new Myxobolus species infecting the gill lamellae of goldfish from Chongqing, China, was described using a comprehensive analysis of morphological, molecular, and histological data. Mature spores were flat-pear in valvular view with tapering anterior and rounded posterior ends, measuring 11.0 ± 0.4 (10.4-11.6) µm in length and 10.3 ± 0.3 (9.6-11.0) µm in width. Two equal-sized elongate pyriform polar capsules were 5.6 ± 0.6 (4.5-6.4) µm long and 3.5 ± 0.5 (2.4-4.1) µm wide. Polar tubules were coiled with 8 or 9 turns. The small-subunit ribosomal DNA gene sequence length of the present species was 1951 nt, and the highest similarity was 97.99% with M. pyramidis. Comparative analysis of the morphological and molecular data revealed that the present species was distinct from other known myxosporeans. Plasmodia were located at the interlamellar troughs nearing the top of the primary gills. Infection by the present species destroyed the original structure of gill lamellae and caused an inflammatory response, eventually leading to fish dyspnea. The morphological, molecular, and pathological data from the present study can be used for aquaculture since they provide guidance for easy detection and future control of this myxosporidiosis.

Multiple Dynamic Bonds-Driven Integrated Cathode/Polymer Electrolyte for Stable All-Solid-State Lithium Metal Batteries.

All-solid-state lithium metal batteries (LMBs) are considered as the promising higher-energy and improved-safety energy-storage systems. Nevertheless, the electrolyte-electrodes interfacial issues due to the limited solid physical contact lead to discontinuous interfacial charge transport and large interfacial resistance, thereby suffering from unsatisfactory electrochemical performance. Herein, we construct an integrated cathode/polymer electrolyte for all-solid-state LMBs under the action of polymer chains exchange and recombination originating from multiple dynamic bonds in our well-designed dynamic supramolecular ionic conductive elastomers (DSICE) molecular structure. The DSICE acts as polymer electrolytes with excellent electrochemical performance and mechanical properties, achieving the ultrathin pure polymer electrolyte thickness (12 µm). Notably, the DSICE also functions as lithium iron phosphate (LiFePO4 , LFP) cathode binders with enhanced adhesive capability. Such well-constructed Li|DSICE|LFP-DSICE cells generate delicate electrolyte-electrodes interfacial contact at the molecular level, providing continuous Li+ transport pathways and promoting uniform Li+ deposition, further delivering superior long-term charge/discharge stability (>600 cycles, Coulombic efficiency, >99.8 %) and high capacity retention (80 % after 400 cycles). More practically, the Li|DSICE|LFP-DSICE pouch cells show stable electrochemical performance, excellent flexibility and safety under abusive tests.

Mass Spectrometry-Based Vitreous Proteomics: Validated Methods and Analysis Pipeline.

Retinal diseases like diabetic retinopathy and age-related macular degeneration affect millions of individuals worldwide and often lead to vision loss. Vitreous fluid abuts the retina, is accessible for sampling, and contains many proteins related to retinal disease. Therefore, analysis of vitreous is an important tool for studying retinal disease. Because it is rich in proteins and extracellular vesicles, mass spectrometry-based proteomics is an excellent method for vitreous analysis. Here, we discuss important variables to consider when performing vitreous proteomics via mass spectrometry.

Phase-Separated Dielectric Gels Based on Christiansen Effect.

Phase separation is a trivial phenomenon but a mature strategy in materials science. The flexible materials are provided toughness and strength by phase separation, yet there are few applications in optics and electronics industry. A novel phase-separated dielectric gel (PSDG) with a strong Christiansen effect is prepared via radical polymerization using hydroxyethyl methacrylate as a monomer, 4-cyano-4'-pentylbiphenyl and tributyl citrate as mixed solvents, and polyethylene glycol as a softener. The solvent ratios and ambient conditions can efficiently change the color of PSDG which makes it strongly selective for the wavelength of transmitted light. Besides, it has a high dielectric constant (10 at 1 kHz), sensitively responding to the electric field. The phase separation degree of PSDG varies with applied electric field, which will induce its transmittance alteration accordingly. The current field sensitive PSDG provides a novel idea for "smart windows". Additionally, varying the size and shape of the electrodes can precisely control the phase separation in PSDG and also enables the function of free writing on flexible materials. Therefore, the designed PSDG has great application potential for flexible touch and interesting interactions.

Morphological and genetic analysis of Ceratomyxa saurida Zhao et al. 2015 and Ceratomyxa mai sp. nov. (Myxozoa: Ceratomyxidae) from the East China Sea.

We describe Ceratomyxa saurida Zhao et al. 2015 and Ceratomyxa mai sp. nov. (Myxozoa: Ceratomyxidae) from the East China Sea. C. saurida was found in the gallbladders of 3/13 specimens of its type host, Saurida elongata Temminck and Schlegel 1846 (Aulopiformes). Myxospore characters were consistent with the original description to which we have added small subunit (SSU) rRNA gene data. C. mai sp. nov. was found in gallbladders of 3/13 specimens of S. elongata and 5/13 specimens of Neobythites sivicola Jordan and Snyder 1901 (Ophidiiformes). Mature myxospores of C. mai sp. nov. were crescentic in sutural view, with a deeply concave posterior angle 142.2±8.2° (125.8‒158.2°) and an arched anterior side. Shell valves were smooth and equal, 20.9±1.9 (17.3‒24.7) µm thick and 9.2±0.5 (8.1‒9.9) µm long, and joined at a straight, thin sutural plane passing between two nematocysts (polar capsules). The nematocysts were equal-sized, pyriform, 2.6±0.2 (2.4‒2.9) µm long and 2.7±0.2 (2.4‒3.3) µm wide, with their tapered ends pointed toward each other, located in the anterior third of the spore. Sequences of the SSU rRNA gene and internal transcribed spacer 1 showed that the isolates of C. mai sp. nov. obtained from S. elongata and N. sivicola were identical. The SSU rRNA gene sequence of C. mai sp. nov. was distinct from all known myxosporeans and clustered with C. saurida, and then with Ceratomyxa filamentosi Kalatzis, Kokkari and Katharios 2013, both of which also infect Aulopiformes fishes.

Molecular characterization and phylogenetic analysis of Paratrichodina africana Kazubski and El-Tantawy, 1986 based on 18S rRNA gene data with the evolutionary hypothesis of trichodinids.

In this study, we provided the morphological data and the first 18S rRNA gene data of Paratrichodina africana Kazubski and El-Tantawy, 1986, isolated from hybrids of Oreochromis niloticus × Oreochromis mossambicus in Chongqing, China. Morphologically, P. africana is mainly characterized by the triangular blade and prominent anterior projection. The present population is consistent with the original populations in the overall appearance of the adhesive disc, and falls within the morphometry range of the original descriptions. Phylogenetically, P. africana was clustered into one large clade with Trichodinella and Tripartiella species, which was nested within Trichodina ones with strong support. By combining morphological and molecular data, our results revealed that the validity of the genus Paratrichodina was doubtful, and suggested that the three genera Trichodinella, Tripartiella, and Paratrichodina should be incorporated into one independent genus. In addition, we provided morphological and molecular data of additional eight trichodinids, and further performed the phylogenetic analysis and traced the evolution history of trichodinids' five morphological and bionomical characters for the first time by taking advantage of the current GenBank data. According to the present results, one evolutionary hypothesis of trichodinids was proposed as follows. The most recent common ancestor of trichodinids inhabiting the freshwater environment as a symbiont of vertebrates should evolve from the ancestor with a long-spiral adoral ciliary turn. The first differentiated Trichodina species should be parasitic on one vertebrate distributed in the freshwater environment. During their evolution, some trichodinids expanded to the marine environment, and some switched to invertebrates in the freshwater environment. The denticle of some freshwater Trichodina species became narrower, and the adoral ciliary spiral turn got shorter, forming the ancestor-oid organism with a short-spiral adoral ciliary turn. Then, those Trichodinella, Tripartiella, and Paratrichodina species might evolve from those ancestor-oid organisms with short-spiral adoral ciliary turn.

The complete mitogenome of the Mugil cephalus (Mugiliformes: Mugilidae) from the Yellow Sea, China.

Mugil cephalus Linnaeus, 1758 is a teleost fish widely distributed in coastal waters that plays an important role in commercial fisheries. In the present study, the complete mitogenome of M. cephalus from the Yellow Sea, China, was sequenced using Illumina Novaseq sequencing. The mitogenome of the M. cephalus was 16,744 bases in length (GenBank accession No. ON262567) including 2 rRNA genes, 22 tRNA genes, 13 protein-coding genes and a D-loop control region. The overall base composition of the genome was 28.2% A, 29.5% C, 26.9% T, and 15.4% G. The analysis of genetic similarity and phylogenetic relationship of M. cephalus from different geographic regions of the world indicated that the species from the Yellow Sea was most similar to NWP1 which is one of the three cryptic species of M. cephalus in Northwestern Pacific.

High Lithium Salt Content PVDF-Based Solid-State Composite Polymer Electrolyte Enhanced by h-BN Nanosheets.

Due to the unique safety qualities, solid composite polymer electrolyte (SCPE) has achieved considerable attentions to fabricate high-energy-density lithium metal batteries, but its overall performance still has to be improved. Herein, a high lithium salt content poly(vinylidene fluoride) (PVDF)-based SCPE was developed, enhanced by hexagonal boron nitride (h-BN) nanosheets, presenting perfect electrochemical performance, fast ion transport, and efficient inhibition of lithium dendrite growth. The optimized SCPE (PVDF-L70-B5) could deliver high ionic conductivity (2.98×10-4  S cm-1 ), ultra-high Li+ ion transfer number (0.62), wide electrochemical stability window (5.24 V), and strong mechanical strength (3.45 MPa) at room temperature. Density functional theory calculation further confirmed that the presence of h-BN could promote the dissociation of bis(trifluoromethanesulfonyl)imide lithium (LiTFSI) and the rapid transfer of Li+ ions. As a result, the assembled symmetric Li/Li battery and asymmetric Li/LiFePO4 battery using PVDF-L70-B5 SCPEs both exhibited high reversible capacity, long-term cycle stability, and high-rate performance when cycled at 60 or 30 °C. The designed SCPEs will open up a new route to synthesize solid-state lithium batteries with high energy density and high safety.

Research on the Construction and Prediction of China's National Fitness Development Index System Under Social Reform.

Background: National fitness is a development plan formulated by China to promote people's participation in leisure and fitness, enhance people's physique, and realize the general goal of strengthening sports. Methods: Based on combing the development process of China's national fitness after reform and opening up, using the improved "balanced scorecard" method, this article constructs an evaluation index system of the national fitness development index. Results: The national fitness development index was established, including 4 first-level indicators, 14 second-level indicators, and 49 third-level indicators. It can calculate the national fitness development index with a total score of 100 points. Conclusion: To verify the feasibility of the evaluation system, the goal current situation evaluation method is used to calculate the national fitness development index during the 14th Five Year Plan period based on the development of national fitness during the 13th Five Year Plan period to provide evaluation tools and theoretical reference for the development of national fitness in China.

Pharmaceutical Reagent Inventory Strategy Based on Contract Shelf Life and Patient Demand.

As the function and R&D level of in vitro diagnostic reagents continue to improve, the need for hospitals for in vitro diagnostic reagents in clinical diagnosis also keeps increasing. However, under the influence of management, process, technology, equipment, materials, employees, and other unexpected disturbing factors, the output of reagents often has random uncertainty, and it is difficult to provide the finished products required by orders on time, in quality and quantity. A secondary supply chain consisting of reagent manufacturers, distributors, and hospitals is constructed, and the inventory control models of in vitro diagnostic reagent supply chain under three strategies of centralized decision-making, hospital-owned inventory, and reagent distributor-managed inventory are established, respectively, and the maximum expected returns of the supply chain system under different strategies are analyzed to achieve the optimal production decision of reagent manufacturers and the optimal procurement decision of hospitals. The results show that reducing the random output probability and patient demand uncertainty has a significant effect on improving the expected return of in vitro diagnostic reagent supply chain, and as the random output probability of reagent manufacturers and patient consumption demand uncertainty increase, the strategy of managing inventory by distributors in collaboration is always better than the strategy of managing inventory by hospitals' own warehouses, which can achieve higher expected return and better inventory quantity, but when the out-of-stock cost of hospitals is too high above a certain threshold, the hospital will tend to adopt the self-inventory strategy.

Small extracellular vesicles induce resistance to anti-GD2 immunotherapy unveiling tipifarnib as an adjunct to neuroblastoma immunotherapy.

BACKGROUND: Anti-GD2 monoclonal antibody immunotherapy has significantly improved the overall survival rate for high-risk neuroblastoma patients. However, 40% of patients fail to respond or develop resistance to treatment, and the molecular mechanisms by which this occurs remain poorly understood. Tumor-derived small extracellular vesicles (sEVs) have emerged as critical regulators in modulating the response to immunotherapy. In this study, we investigated the role of neuroblastoma-derived sEVs in promoting resistance to the anti-GD2 monoclonal antibody dinutuximab. Moreover, to determine whether pharmacologic inhibition of sEV secretion sensitizes tumors to dinutuximab treatment, we combined dinutuximab with tipifarnib, a farnesyltransferase inhibitor that inhibits sEV secretion. METHODS: We investigated the role of neuroblastoma-derived sEVs in modulating the response to dinutuximab by utilizing the syngeneic 9464D-GD2 mouse model. The effect of neuroblastoma-derived sEVs in modulating the tumor microenvironment (TME) and host immune system were evaluated by RNA-sequencing and flow cytometry. Importantly, we used this mouse model to investigate the efficacy of tipifarnib in sensitizing neuroblastoma tumors to dinutuximab. The effect of tipifarnib on both the TME and host immune system were assessed by flow cytometry. RESULTS: We demonstrated that neuroblastoma-derived sEVs significantly attenuated the efficacy of dinutuximab in vivo and modulated tumor immune cell infiltration upon dinutuximab treatment to create an immunosuppressive TME that contains more tumor-associated macrophages and fewer tumor-infiltrating NK cells. In addition, we demonstrated that neuroblastoma-derived sEVs suppress splenic NK cell maturation in vivo and dinutuximab-induced NK cell-mediated antibody-dependent cellular cytotoxicity in vitro. Importantly, tipifarnib drastically enhanced the efficacy of dinutuximab-mediated inhibition of tumor growth and prevented the immunosuppressive effects of neuroblastoma-derived sEVs in vivo. CONCLUSIONS: These preclinical findings uncover a novel mechanism by which neuroblastoma-derived sEVs modulate the immune system to promote resistance to dinutuximab and suggest that tipifarnib-mediated inhibition of sEV secretion may serve as a viable treatment strategy to enhance the antitumor efficacy of anti-GD2 immunotherapy in high-risk neuroblastoma patients.

Morphological description and molecular identification of Myxobolus dajiangensis n. sp. (Myxozoa: Myxobolidae) from the gill of Cyprinus carpio in southwest China.

Background: Myxosporean diversity is a hot topic since they are difficult to accurately identify and classify. Many Myxobolus parasites have been named as Myxobolus koi because of their similar morphological features with the species originally reported. However, the distinctions in fine morphological features, host specificity, and molecular data have given rise to the attention of researchers. Methods: The classical morphometric and histological methods were used to describe the Myxobolus dajiangensis n. sp. in morphology. The common techniques in modern molecular biology and the methods of phylogenetic analyses were combined to identify the species. Results: Plasmodia of interlamellar-vascular type were found in the vascular network of gill lamellae. Mature myxospores of M. dajiangensis n. sp. were elongated and pyriform from the frontal view. The myxospores were 14.8 ± 0.4 (13.9-15.6) µm in length, 8.0 ± 0.5 (7.2-9.1) µm in width, and 5.5 µm in thickness. The two polar capsules were pyriform and slightly different in length. The length of the larger polar capsules was 8.0 ± 0.4 (7.1-8.8) µm, and it was 7.4 ± 0.4 (6.1-8.0) µm for the smaller ones. The width of both polar capsules was 2.5 ± 0.2 (2.0-3.2) µm. The polar filaments within the polar capsules were each coiled nine to 11 turns. Comparative analysis of both the morphological and molecular data between the present speices and other similar species revealed that the present species is a novel species, Myxobolus dajiangensis n. sp. Also, M. koi (FJ710800) was misidentified and the congener with M. dajiangensis n. sp., depending on the secondary structures of SSU rRNA and phylogenetic analysis. Moreover, the cryptic species existed in the M. koi parasites.

A validated analysis pipeline for mass spectrometry-based vitreous proteomics: new insights into proliferative diabetic retinopathy.

BACKGROUND: Vitreous is an accessible, information-rich biofluid that has recently been studied as a source of retinal disease-related proteins and pathways. However, the number of samples required to confidently identify perturbed pathways remains unknown. In order to confidently identify these pathways, power analysis must be performed to determine the number of samples required, and sample preparation and analysis must be rigorously defined. METHODS: Control (n = 27) and proliferative diabetic retinopathy (n = 23) vitreous samples were treated as biologically distinct individuals or pooled together and aliquoted into technical replicates. Quantitative mass spectrometry with tandem mass tag labeling was used to identify proteins in individual or pooled control samples to determine technical and biological variability. To determine effect size and perform power analysis, control and proliferative diabetic retinopathy samples were analyzed across four 10-plexes. Pooled samples were used to normalize the data across plexes and generate a single data matrix for downstream analysis. RESULTS: The total number of unique proteins identified was 1152 in experiment 1, 989 of which were measured in all samples. In experiment 2, 1191 proteins were identified, 727 of which were measured across all samples in all plexes. Data are available via ProteomeXchange with identifier PXD025986. Spearman correlations of protein abundance estimations revealed minimal technical (0.99-1.00) and biological (0.94-0.98) variability. Each plex contained two unique pooled samples: one for normalizing across each 10-plex, and one to internally validate the normalization algorithm. Spearman correlation of the validation pool following normalization was 0.86-0.90. Principal component analysis revealed stratification of samples by disease and not by plex. Subsequent differential expression and pathway analyses demonstrated significant activation of metabolic pathways and inhibition of neuroprotective pathways in proliferative diabetic retinopathy samples relative to controls. CONCLUSIONS: This study demonstrates a feasible, rigorous, and scalable method that can be applied to future proteomic studies of vitreous and identifies previously unrecognized metabolic pathways that advance understanding of diabetic retinopathy.

Morphological redescription and molecular characterization of Trichodina matsu Basson amp; Van As, 1994 (Ciliophora, Mobilida, Trichodinidae) infecting Tachysurus fulvidraco (Richardson, 1846) from Chongqing, China.

During a survey of parasitic ciliates in Chongqing, China, Trichodina matsu Basson Van As, 1994 was isolated from gills of Tachysurus fulvidraco. Furthermore, the 18S rRNA gene and ITS-5.8S rRNA region of T. matsu were sequenced for the first time and applied for the species identification and comparison with similar species in the present study. Based on the morphological and molecular comparisons, the results indicate that T. matsu is an ectoparasite specific for the Siluriformes catfish. Based on the analyses of genetic distance, multiple sequence alignments, and phylogenetic analyses, no obvious differentiation within populations of T. matsu was found. In addition, the 'Trichodina hyperparasitis (KX904933) in GenBank is a misidentification and appears to be conspecific with T. matsu according to the comparison of morphological and molecular data.

Research on the investment efficiency based on grey correlation-DEA model.

Small and medium-sized enterprises (SMEs) are an important part of stimulating market vitality. In the post-pandemic era, the ability of SMEs to absorb employment plays an important role in stabilizing society and promoting economic growth. This paper selects 226 sample data from 2014 to 2017 measures the investment efficiency of small and medium-sized enterprises and makes a further analysis its influencing factors. Because there is a lag between investment and output. In this paper, the grey correlation analysis is used. Measuring the investment efficiency of SMEs by using BBC-DEA method. The study found that the overall investment efficiency of SMEs is low. Considering from the inside of the enterprise, this paper uses the Tobit model to make an empirical analysis. It is found that the influence of board structure and agency cost on investment efficiency are significantly negative. Growth, ownership concentration, equity incentive, salary incentive, profitability of SMEs have a significant positive effect on the investment efficiency of enterprises.