A stable low-temperature H2-production catalyst by crowding Pt on α-MoC.

The water-gas shift (WGS) reaction is an industrially important source of pure hydrogen (H2) at the expense of carbon monoxide and water1,2. This reaction is of interest for fuel-cell applications, but requires WGS catalysts that are durable and highly active at low temperatures3. Here we demonstrate that the structure (Pt1-Ptn)/α-MoC, where isolated platinum atoms (Pt1) and subnanometre platinum clusters (Ptn) are stabilized on α-molybdenum carbide (α-MoC), catalyses the WGS reaction even at 313 kelvin, with a hydrogen-production pathway involving direct carbon monoxide dissociation identified. We find that it is critical to crowd the α-MoC surface with Pt1 and Ptn species, which prevents oxidation of the support that would cause catalyst deactivation, as seen with gold/α-MoC (ref. 4), and gives our system high stability and a high metal-normalized turnover number of 4,300,000 moles of hydrogen per mole of platinum. We anticipate that the strategy demonstrated here will be pivotal for the design of highly active and stable catalysts for effective activation of important molecules such as water and carbon monoxide for energy production.

High-performance multi-junction cascade 1.3†µm quantum dot vertical cavity surface-emitting laser.

A high-performance 5-junction cascade quantum dot (QD) vertical cavity surface-emitting laser (VCSEL) with 1.3 µm wavelength was designed. The characteristics of the QD as active regions and tunnel junctions are combined to effectively increase output power. The photoelectric characteristics of single-junction, 3-junction cascade, and 5-junction cascade QD VCSELs are compared at continuous-wave conditions. Results indicate that the threshold current gradually decreases, and the output power and slope efficiency exponential increase with the increase of the number of active regions. The peak power conversion efficiency of 58.4% is achieved for the 5-junction cascade individual QD VCSEL emitter with 10 µm oxide aperture. The maximum slope efficiency of the device is 6.27 W/A, which is approximately six times than that of the single-junction QD VCSEL. The output power of the 5-junction cascade QD VCSEL reaches 188.13 mW at injection current 30 mA. High-performance multi-junction cascade 1.3-µm QD VCSEL provides data and theoretical support for the preparation of epitaxial materials.

A manganese-based catalyst system for general oxidation of unactivated olefins, alkanes, and alcohols.

Non-noble metal-based catalyst systems consisting of inexpensive manganese salts, picolinic acid and various heterocycles enable epoxidation of the challenging (terminal) unactivated olefins, selective C-H oxidation of unactivated alkanes, and O-H oxidation of secondary alcohols with aqueous hydrogen peroxide. In the presence of the in situ generated optimal manganese catalyst, epoxides are generated with up to 81% yield from alkenes and ketone products with up to 51% yield from unactivated alkanes. This convenient protocol allows the formation of the desired products under ambient conditions (room temperature, 1 bar) by employing only a slight excess of hydrogen peroxide with 2,3-butadione as a sub-stoichiometric additive.

Practical gram-scale synthesis of bicyclol metabolites M2 and M3.

Bicyclol, an innovative hepatoprotective drug, was approved by the Chinese National Medical Products Administration (NMPA) in 2001 to treat Hepatitis B and drug-induced liver injury. Two active metabolites of bicyclol have been identified as M2 and M3. To evaluate the impact on drug safety and efficacy of possible drug-drug interactions (DDIs) associated with these metabolites, a sufficient quantity of these metabolites is required. Herein, we report a concise novel route for the synthesis of M2 and M3 using the Suzuki-Miyaura coupling as the key step. Furthermore, we complete the gram-scale syntheses of M2 and M3.

Key circRNAs from goat: discovery, integrated regulatory network and their putative roles in the differentiation of intramuscular adipocytes.

BACKGROUND: The procession of preadipocytes differentiation into mature adipocytes involves multiple cellular and signal transduction pathways. Recently. a seirces of noncoding RNAs (ncRNAs), including circular RNAs (circRNAs) were proved to play important roles in regulating differentiation of adipocytes. RESULT: In this study, we aimed to identificate the potential circRNAs in the early and late stages of goat intramuscular adipocytes differentiation. Using bioinformatics methods to predict their biological functions and map the circRNA-miRNA interaction network. Over 104 million clean reads in goat intramuscular preadipocytes and adipocytes were mapped, of which16 circRNAs were differentially expressed (DE-circRNAs). Furthermore, we used real-time fluorescent quantitative PCR (qRT-PCR) technology to randomly detect the expression levels of 8 circRNAs among the DE-circRNAs, and our result verifies the accuracy of the RNA-seq data. From the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of the DE-circRNAs, two circRNAs, circ_0005870 and circ_0000946, were found in Focal adhesion and PI3K-Akt signaling pathway. Then we draw the circRNA-miRNA interaction network and obtained the miRNAs that possibly interact with circ_0005870 and circ_0000946. Using TargetScan, miRTarBase and miR-TCDS online databases, we further obtained the mRNAs that may interact with the miRNAs, and generated the final circRNA-miRNA-mRNA interaction network. Combined with the following GO (Gene Ontology) and KEGG enrichment analysis, we obtained 5 key mRNAs related to adipocyte differentiation in our interaction network, which are FOXO3(forkhead box O3), PPP2CA (protein phosphatase 2 catalytic subunit alpha), EEIF4E (eukaryotic translation initiation factor 4), CDK6 (cyclin dependent kinase 6) and ACVR1 (activin A receptor type 1). CONCLUSIONS: By using Illumina HiSeq and online databases, we generated the final circRNA-miRNA-mRNA interaction network that have valuable functions in adipocyte differentiation. Our work serves as a valuable genomic resource for in-depth exploration of the molecular mechanism of ncRNAs interaction network regulating adipocyte differentiation.

Protein elicitor GP1pro targets aquaporin NbPIP2;4 to activate plant immunity.

The novel protein elicitor GP1pro is the protein component of glycoprotein GP-1 isolated and identified from Streptomyces kanasensis ZX01. GP1pro induces the production of reactive oxygen species (ROS) and a hypersensitive response (HR), along with the accumulation of resistance-related genes and secondary metabolites. It ultimately regulates plant defence responses. Further analysis revealed that GP1pro interacts with the PIP2-family aquaporin protein NbPIP2;4 on the plant plasma membrane (PM) in Nicotiana benthamiana. PM localization is necessary for inducing GP1pro resistance. These results demonstrate that NbPIP2;4 acts as a H2 O2 transporter to positively regulate plant immunity and ROS accumulation. In summary, this study elucidates a conserved and novel pathway caused by GP1pro to initiate host cellular defences by targeting the plant aquaporin protein NbPIP2;4 and transporting apoplast-to-cytoplast H2 O2 to regulate plant immunity.

Antiresonant fiber structures based on swarm intelligence design.

In this work, we obtained a new, to the best of our knowledge, structure of anti-resonant fiber (ARF) by an adaptive particle swarm optimization (PSO) algorithm. Different from the prior method of stacking elemental parts and optimizing parameters through experience or algorithm, we decompose some classic structures into points and optimize the positions of these points through swarm intelligence. The fiber structure is reconstructed by interpolation, and some new structures with low confinement loss (CL) and high higher order mode extinction ratio (HOMER) are obtained. These novel ARFs exhibit similar structural characteristics, and are named as "the bulb-shaped ARFs". Among these structures, the minimum achieved CL is 2.21 × 10-5dB/m at 1300 nm and the maximum achieved HOMER exceeds 14,000. This work provides a method with high degree of freedom in the design of non-uniform cross-section waveguides and helps to discover new fiber structures.

Initial stage of carbonization of iron during hydrocarbons dissociation: a molecular dynamics study.

The carbonization of iron is a very important early phenomenon in the field of heterogeneous catalysis and the petrochemical industry, but the mechanism is still controversial. In this work, the carbonization mechanism and carbonization structure of iron nanoparticles by different carbon sources (CH4, C2H6, C2H4, C2H2) were systematically investigated using the reactive molecular dynamics method. The results show that saturated alkanes are dehydrogenated while adsorbed, but unsaturated olefins and alkynes undergo bond-breaking while adsorbed. The C-H bond is more likely to break than the C-C bond. Hydrocarbons with high carbon content have a strong ability to carbonize Fe nanoparticles under the same conditions. For C2H4 and C2H2, the C atoms generated from dissociation form a large number of long carbon chains intertwined with branched chains and multiple carbon rings. The C2 species formed by C2H2 after complete dehydrogenation diffuse rapidly to the interior of the nanoparticles, releasing the surface active sites and accelerating the carbonization process. Carbon-rich iron carbides (FeCx) with different Fe/C ratios were obtained by carbonization with different carbon sources. In addition, the Fe(110) surface exhibits the strongest carburizing ability. These findings provide systematic insights into the initial stages of metal Fe carburization.

Low-temperature hydrogen production from water and methanol using Pt/α-MoC catalysts.

Polymer electrolyte membrane fuel cells (PEMFCs) running on hydrogen are attractive alternative power supplies for a range of applications, with in situ release of the required hydrogen from a stable liquid offering one way of ensuring its safe storage and transportation before use. The use of methanol is particularly interesting in this regard, because it is inexpensive and can reform itself with water to release hydrogen with a high gravimetric density of 18.8 per cent by weight. But traditional reforming of methanol steam operates at relatively high temperatures (200-350 degrees Celsius), so the focus for vehicle and portable PEMFC applications has been on aqueous-phase reforming of methanol (APRM). This method requires less energy, and the simpler and more compact device design allows direct integration into PEMFC stacks. There remains, however, the need for an efficient APRM catalyst. Here we report that platinum (Pt) atomically dispersed on α-molybdenum carbide (α-MoC) enables low-temperature (150-190 degrees Celsius), base-free hydrogen production through APRM, with an average turnover frequency reaching 18,046 moles of hydrogen per mole of platinum per hour. We attribute this exceptional hydrogen production-which far exceeds that of previously reported low-temperature APRM catalysts-to the outstanding ability of α-MoC to induce water dissociation, and to the fact that platinum and α-MoC act in synergy to activate methanol and then to reform it.

Paravertebral Muscle Morphology in L4-L5 Disc Herniation: Insights from the Michigan State University Classification.

BACKGROUND Lumbar disc herniation (LDH) at L4-L5 impacts paravertebral muscle morphology. Intervertebral disc degeneration is linked to paravertebral muscle changes, affecting LDH treatment outcomes. This study explored L4-L5 LDH paravertebral muscle alterations, specifically in the erector spinae, multifidus, and psoas major, using Michigan State University's classification to guide LDH treatment. MATERIAL AND METHODS The study enrolled 160 patients, including 39 normal patients and 121 L4-L5 LDH patients. Patients with LDH were grouped according to MSU classification and compared to the normal group according to demographics and imaging changes. RESULTS In patients with L4-L5 herniation in Zone B, the FI of the ES muscle at L3-L4 level, L4-L5 level, and L5-S1 level was higher than that of normal people (P=0.018, P=0.043, P=0.010, respectively), and there was no difference between FI of MF and normal people. The Zone B patients also had a smaller CSA of the ES muscle at L4-L5 level than that in the normal group (P=0.049). Patients in the Zone C group were older than those in the normal group (P=0.014). The CSA of the PM of patients with Grade 3 herniation differed from that of the normal group at the L4-L5 and L5-S1 level. They were higher than in normal people at L4-L5 level (P=0.011) and lower at L5-S1 level (P=0.028). CONCLUSIONS In patients with L4-L5 herniation in Zone B, the FI of ES at L3-S1 level was higher than in normal people, and the CSA at L4-L5 level was smaller than in normal people. In patients with Grade3 herniation, PM CSA was larger at L4-L5 level and smaller at L5-S1 level than in normal people.

CircRRAS2 promotes myogenic differentiation of bovine MuSCs and is a novel regulatory molecule of muscle development.

The proliferation and myogenic differentiation of muscle stem cells (MuSCs) are important factors affecting muscle development and beef quality. There is increasing evidence that circRNAs can regulate myogenesis. We found a novel circRNA, named circRRAS2 that is significantly upregulated in the differentiation phase of bovine MuSCs. Here, we aimed to determine its roles in the proliferation and myogenic differentiation of these cells. The results showed that circRRAS2 was expressed in several bovine tissues. CircRRAS2 inhibited MuSCs proliferation and promoted myoblast differentiation. In addition, chromatin isolation by using RNA purification and mass spectrometry in differentiated muscle cells identified 52 RNA-binding proteins that could potentially bind to circRRAS2, in order to regulate their differentiation. The results suggest that circRRAS2 could be a specific regulator of myogenesis in bovine muscle.HighlightsCircRRAS2 expression is higher in DM cells than in GM cells.CircRRAS2 could significantly inhibit the proliferation and apoptosis of bovine MuSCs.CircRRAS2 promotes the differentiation of bovine MuSCs into myotubes.CircRRAS2 may exert regulatory effects through multiple RNA binding proteins.

Ceratocystis fimbriata Causing Postharvest Fruit Rot of Pear in Punjab, Pakistan.

Pear (Pyrus communis) is an important deciduous fruit cultivated on a worldwide scale including Pakistan. During August 2021, a postharvest fruit rot disease was observed on several pears at various farmers market in Okara- a district of Punjab Province, Pakistan. The incidence of the disease varied from 7 to 20% with 35% disease severity. Necrotic spots (10 to 20 mm diameter) were first observed on the infected pear fruit. The spots enlarged gradually and developed into a brown, water-soaked and rotted lesion. Eventually, the whole fruit became soft, rotted and covered with a gray-brown mycelium. The isolates were obtained from the symptomatic tissues (n = 18) incubated on carrot discs that had been surface sterilized in 100-ppm streptomycin solution. After consistent sporulation of a fungus on the carrot discs, the ascospore masses formed at the tip of perithecia were transferred to malt extract agar (MEA). Primary conidia were cylindrical and hyaline (7 to 11 × 4 to 7 µm) and secondary conidia were hyaline and barrel-shaped (7 to 12 × 5 to 8 µm). Endoconidiophores with primary conidia were (12 to 27 × 2.6 to 5.5 µm). Perithecia produced on carrot discs were dark brown to black, and the base was 157 to 278 µm in diameter. Ascomatal necks were 512 to 656 µm long, dark brown to black, lighter in color at apices, tapering from base (23 to 45 µm diameter) to apex (13 to 24 µm diameter). Ostiolar hyphae were 41 to 79 µm long. Ascospores were hyaline, hat shaped, 3 to 4 µm long, and accumulated in a sticky matrix at the tips of perithecial necks. Mycelium was initially hyaline but became dark greenish brown after 7 days. Dark brown, thick-walled aleuroconidia (13 to 19.5 × 9 to 14 µm) appeared on culture plates after 2 months. Based on morphological characteristics, the fungus was identified as Ceratocystis fimbriata (Engelbrecht, 2005; Suwandi et al. 2021). To further confirm species identification, genomic DNA of two representative isolates (UO-05 and UO-06) was obtained using an extraction kit. The internal transcribed spacer (ITS) region was amplified using ITS1/4 (White et al. 1990). A BLAST search with GenBank accession nos. OR185451 and OR185456 indicated 99 to 100% identity with several C. fimbriata including type species (MH856050.1; KC493160.1; MT560374.1). Pathogenicity tests were conducted by inoculating nine disease-free pear (cv. Concord) fruit after disinfesting in 75% ethanol. A prepared spore suspension (1.0 × 106 spores/ml) was dropped on the wounds (a depth of 1 mm diameter) on the pear surface, which were made by a sterilized needle. 10 µl of a prepared spore suspension was dropped onto nine pears. Sterile water (10 µl) was dropped on the wounded sites of nine pear fruits as negative controls and all fruits were incubated in a growth chamber at 30/26°C (day/night, 90% relative humidity). Symptoms similar to those on the naturally infected fruits began after 4 to 5 days of inoculation, while controls remained healthy. The fungal isolates recovered from inoculated pears were morphologically identical to the C. fimbriata isolates originally recovered from symptomatic fruits fulfilling Koch's postulates. The pathogen has been reported to cause postharvest fruit rot of passion fruit and cucumber (Firmino et al. 2016; Li et al. 2019). To our knowledge, this is the first report of C. fimbriata causing fruit rot of pear in Punjab Province. The detection of this disease will help pear growers to take actions to monitor and prevent disease outbreak as well as develop an effective management practice when it occurs.

[Research Progress in Niacinamide in the Prevention and Treatment of Mouth and Systemic Diseases].

Nicotinamide (NAM) is the amide form of niacin and one of the precursors of nicotinamide adenine dinucleotide (NAD +). NAM can be used as a dietary supplement or clinical therapeutic drug to replenish NAD + levels in the human body and participate in key bodily functions such as cellular metabolism and DNA repair. NAM has the advantage of low cost, wide availability, and sound biosafety. It also has multiple biological functions, including antibacterial effect, anti-inflammatory effect, and modulation of cellular immunity, producing significant ameliorative effects on skin and neurodegenerative diseases. However, most studies on NAM are still at the laboratory stage. Herein we reviewed the role and mechanism of NAM in the prevention and treatment of oral and systemic diseases, explored its potential as clinical therapeutic medication, provided some basis and references for the clinical application of nicotinamide in the prevention and treatment of various diseases, and discussed its prospects for future research and application.

Effect of Ga1-xInxAs1-yPy Al-free asymmetric barrier on GaAs-based 808-nm laser diode.

A GaInAsP/GaAs/GaAsP Al-free laser with asymmetric potential barriers is designed theoretically to prevent carrier leakage. The band alignment demonstrates that a high height of the potential barrier decreases the leakage current. The internal quantum efficiency increases by increasing the injection efficiency, which is attributed to the decreasing electron potential barrier heights. Moreover, the threshold current and operating voltage decrease by adopting a novel barrier so that the output power and power conversion efficiency (PCE) increase. When the injection current is 5 kA/cm2, the PCE is 77.82% and the output power is 13.21 W. The physical mechanism of potential barrier heights affecting carrier transport is investigated, which will provide a theoretical basis for optimizing laser diodes.

Facile one-pot iodine gas phase doping on 2D MoS2/CuS FET at room temperature.

Electronic devices composed of semiconducting two-dimensional (2D) materials and ultrathin 2D metallic electrode materials, accompanying synergistic interactions and extraordinary properties, are becoming highly promising for future flexible and transparent electronic and optoelectronic device applications. Unlike devices with bulk metal electrode and 2D channel materials, devices with ultrathin 2D electrode and 2D channel are susceptible to chemical reactions in both channel and electrode surface due to the high surface to volume ratio of the 2D structures. However, so far, the effect of doping was primary concerned on the channel component, and there is lack of understanding in terms of how to modulate electrical properties of devices by engineering electrical properties of both the metallic electrode and the semiconducting channel. Here, we propose the novel, one-pot doping of the field-effect transistor (FET) based on 2D molybdenum disulfide (MoS2) channel and ultrathin copper sulfide (CuS) electrodes under mild iodine gas environment at room temperature, which simultaneously modulates electrical properties of the 2D MoS2channel and 2D CuS electrode in a facile and cost-effective way. After one-pot iodine doping, effective p-type doping of the channel and electrode was observed, which was shown through decreased off current level, improvedIon/Ioffratio and subthreshold swing value. Our results open up possibility for effectively and conveniently modulating electrical properties of FETs made of various 2D semiconductors and ultrathin contact materials without causing any detrimental damage.

Comprehensive analysis of dihydromyricetin metabolites in rats using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry.

As the most abundant and bioactive constituent in vine tea (Ampelopsis grossedentata), dihydromyricetin possesses numerous biological activities. A rapid profiling and identification method for dihydromyricetin metabolites in rats after the oral administration has been established using ultra-high-performance liquid chromatography-Q-Exactive Orbitrap mass spectrometry coupled with multiple data-mining methods. Herein, an efficient analytical strategy characterized by a parallel reaction monitoring mode combining diagnostic fragment ions filtering techniques was developed for the comprehensive identification of dihydromyricetin metabolites in rat plasma, urine, and feces. And then, the biotransformation pathways of dihydromyricetin were further revealed. As a result, a total of 49 metabolites were finally identified by comparing diagnostic fragment ions, chromatographic retention times, neutral loss fragment ions, and accurate mass measurement with those of the dihydromyricetin reference standard. These metabolites were presumed to be dominantly generated through hydroxylation, dehydroxylation, methylation, reduction, sulfation, decarbonylation, glucuronidation, glucosylation, and their composite reactions. In a word, our present results not only supplied a solid foundation to better understand the action mechanism of dihydromyricetin, but also provided some models for the metabolism study of the other compounds in traditional Chinese medicines or natural plants.

[Inhibitory Effects of Nicotinamide on Streptococcus mutans Growth and Biofilm Formation].

Objective: To explore the effects of nicotinamide (NAM) on the growth, biofilm formation and exopolysaccharides (EPS) production of Streptococcus mutans. Methods: The minimum inhibitory concentration (MIC) of NAM on S. mutanswas determined by the planktonic bacterial susceptibility assay. The NAM mass concentrations were set as 1/2 MIC, 1/4 MIC and 1/8 MIC for hree separate treatment groups. Culture medium without NAM was used in the negative control group and culture medium containing 0.1 mg/mL NaF was used for the positive control group (except for the scanning electron microscopy). The growth curves of S. mutans under different NAM concentrations were drawn. Crystal violet assay and anthrone-sulfuric acid method were used to explore the effects of NAM on S. mutans biofilm formation and water-insoluble EPS production, respectively. The morphology and structure of S. mutansplanktons and biofilms after NAM treatment were observed by scanning electron microscopy. Results: The MIC of NAM on S. mutans was 32 µg/µL. After 16 µg/µL (1/2 MIC), 8 µg/µL (1/4 MIC) and 4 µg/µL (1/8 MIC) NAM treatments, S. mutans growth and biofilm formation were inhibited, with the 16 µg/µL NAM group displaying the most significant inhibitory effects. The synthesis of EPS decreased significantly in the 16 µg/µL and 8 µg/µL NAM groups in comparison with that of the negative control group (P<0.05). Under scanning electron microscope, the cell length of S. mutans was shortened, the cell width was extended, and the length/width ratio was decreased, showing significant difference when comparing the 16 µg/µL and 8 µg/µL NAM groups with the negative control group (P<0.05). Conclusion: Under the influence of NAM at certain concenrations, the growth, biofilm formation, and EPS synthesis of S. mutanswere inhibited.

Atomically Dispersed Ni/α-MoC Catalyst for Hydrogen Production from Methanol/Water.

Methanol-water reforming is a promising solution for H2 production/transportation in stationary and mobile hydrogen applications. Developing inexpensive catalysts with sufficiently high activity, selectivity, and stability remains challenging. In this paper, nickel-supported over face-centered cubic (fcc) phase α-MoC has been discovered to exhibit extraordinary hydrogen production activity in the aqueous-phase methanol reforming reaction. Under optimized condition, the hydrogen production rate of 2% Ni/α-MoC is about 6 times higher than that of conventional noble metal 2% Pt/Al2O3 catalyst. We demonstrate that Ni is atomically dispersed over α-MoC via carbon bridge bonds, forming a Ni1-Cx motif on the carbide surface. Such Ni1-Cx motifs can effectively stabilize the isolated Ni1 sites over the α-MoC substrate, rendering maximized active site density and high structural stability. In addition, the synergy between Ni1-Cx motif and α-MoC produces an active interfacial structure for water dissociation, methanol activation, and successive reforming processes with compatible activity.

Simple mechanisms of CH4 reforming with CO2 and H2O on a supported Ni/ZrO2 catalyst.

To understand the metal-support interaction of oxide supported transition metal catalysts, we computed the reaction mechanisms of dry and steam reforming of methane on a tetragonal ZrO2(101) supported Ni catalyst. Based on the limited number of active sites on the surface, an irregular and non-ideal Ni13 cluster on ZrO2(101) is identified as a catalyst. A simple reaction mechanism is proposed, and the first direct dissociation step of CO2, CH4 and H2O is the most difficult based on the computed Gibbs free energies and no surface CHXO and CHXOH intermediates are involved, different from that on the flat Ni(111) surface. Analysis of other supported nickel catalysts shows that not only the support but also the size and shape of the metal clusters play an important role in the reaction mechanisms and kinetics.

Associations of Changes in Serum Inflammatory Factors, MMP-3, 25(OH)D and Intestinal Flora with Osteoporosis and Disease Activity in Rheumatoid Arthritis Patients.

BACKGROUND: To explore the associations of changes in serum inflammatory factors, matrix metalloproteinase-3 (MMP-3), 25-hydroxy vitamin D [25(OH)D], and intestinal flora with osteoporosis and disease activity in rheumatoid arthritis (RA) patients, so as to provide references for clinical diagnosis and treatment. METHODS: A total of 98 RA patients were selected as the objects of study (RA group), and divided into active-stage group (n = 56) and remission-stage group (n = 42) according to the disease activity score (DAS28). Another 50 healthy people receiving physical examination in our hospital during the same period were selected as the control group. The changes in serum inflammatory factors, MMP-3, 25(OH)D, and intestinal flora were compared among the three groups, and the osteoporosis of the subjects was analyzed in each group. Moreover, the associations of changes in serum inflammatory factors, MMP-3, 25(OH)D, and intestinal flora with osteoporosis and disease activity in RA patients were analyzed using the Pearson's method. RESULTS: Compared with those in the control group, the levels of serum MMP-3, interleukin-6 (IL-6), IL-10, and C-reactive protein (CRP). The Escherichia coli count were significantly increased, while the level of serum 25(OH)D, bone mineral density (BMD), and Lactobacillus and Bifidobacterium counts were significantly decreased in the active-stage group and remission-stage group, more obviously in active-stage group (p < 0.05). The osteoporosis and disease activity in RA patients were positively correlated with serum IL-6, IL-10, CRP, MMP-3, Escherichia coli and BMD, but negatively correlated with 25(OH)D, Lactobacillus and Bifidobacterium (p < 0.05), and not correlated with the sharp score (p > 0.05). CONCLUSIONS: There are certain associations of changes in serum inflammatory factors, MMP-3, 25(OH)D, and in-testinal flora with osteoporosis and disease activity in RA patients, showing certain value in clinical application.