85 research outputs found

    The Murine Reg3a Stimulated by Lactobacillus casei Promotes Intestinal Cell Proliferation and Inhibits the Multiplication of Porcine Diarrhea Causative Agent in vitro

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    Lactobacillus casei (L. casei), a normal resident of the gastrointestinal tract of mammals, has been extensively studied over the past few decades for its probiotic properties in clinical and animal models. Some studies have shown that some bacterium of Lactobacillus stimulate the production of antimicrobial peptides in intestinal cells to clear enteric pathogens, however, which antimicrobial peptides are produced by L. casei stimulation and its function are still not completely understood. In this study, we investigated the changes of antimicrobial peptides’ expression after intragastric administration of L. casei to mice. The bioinformatics analysis revealed there were nine genes strongly associated with up-regulated DEGs. But, of these, only the antimicrobial peptide mReg3a gene was continuously up-regulated, which was also confirmed by qRT-PCR. We found out the mReg3a expressed in engineering E.coli promoted cell proliferation and wound healing proved by CCK-8 assay and wound healing assay. Moreover, the tight junction proteins ZO-1 and E-cadherin in mReg3a treatment group were significantly higher than that in the control group under the final concentration of 0.2 mg/ml both in Porcine intestinal epithelial cells (IPEC-J2) and Mouse intestinal epithelial cells (IEC-6) (p < 0.05). Surprisingly, the recombinant mReg3a not only inhibited Enterotoxigenic Escherichia coli (ETEC), but also reduced the copy number of the piglet diarrheal viruses, porcine epidemic diarrhea virus (PEDV), porcine transmissible gastroenteritis virus (TGEV), and porcine rotavirus (PoRV), indicating the antimicrobial peptides mReg3a may be feed additives to resist the potential of the intestinal bacterial and viral diarrhea disease

    Orbital parameters for an ELM white dwarf with a white dwarf companion: LAMOST J033847.06+413424.2

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    Double white dwarf systems are of great astrophysical importance in the field of gravitational wave and Type Ia supernova. While the binary fraction of CO core white dwarf is about a few percents, the extremely low mass white dwarfs are all thought to be within binary systems. In this work, we report the orbital solution of a double degenerate system: J033847.06+413424.24, an extremely low mass He core white dwarf orbiting a CO core white dwarf. With LAMOST and P200, time domain spectroscopic observations have been made and spectral atmosphere parameters are estimated to be Teff22500T_{\rm eff}\sim22500 K and log g5.6g\sim5.6 dex. Combining Gaia parallax, 3D extinction, and evolution tracks, we estimate a radius of 0.12\sim0.12 RR_{\odot} and a mass of 0.22\sim0.22 MM_{\odot}. With the 37 single exposure spectra, the radial velocities are measured and the orbital parameters are estimated to be P=0.1253132(1)P=0.1253132(1) days, K1=289±4K1=289\pm4 km/s and Vsys=41±3V_{sys}=-41\pm3 km/s. The radial velocity based system ephemeris is also provided. The light curves from several photometric surveys show no orbital modulation. The orbital solution suggests that the invisible companion has a minimum mass of about 0.60 MM_{\odot} and is 0.79\sim0.79 MM_{\odot} for an inclination of 60.060.0^{\circ}, indicating most probably a CO core white dwarf. The system is expected to merge in about 1 Gyr. With present period and distance (596\sim596 pc) it can not irradiate strong enough gravitational wave for LISA. More double degenerate systems are expected to be discovered and parameterized as the LAMOST survey goes on.Comment: 12 pages, 11 figure

    Isolation and Characterization of Cytotoxic, Aggregative Citrobacter freundii

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    Citrobacter freundii is an infrequent but established cause of diarrhea in humans. However, little is known of its genetic diversity and potential for virulence. We analyzed 26 isolates, including 12 from human diarrheal patients, 2 from human fecal samples of unknown diarrheal status, and 12 from animals, insects, and other sources. Pulsed field gel electrophoresis using XbaI allowed us to divide the 26 isolates into 20 pulse types, while multi-locus sequence typing using 7 housekeeping genes allowed us to divide the 26 isolates into 6 sequence types (STs) with the majority belonging to 4 STs. We analyzed adhesion and cytotoxicity to HEp-2 cells in these 26 strains. All were found to adhere to HEp-2 cells. One strain, CF74, which had been isolated from a goat, showed the strongest aggregative adhesion pattern. Lactate dehydrogenase (LDH) released from HEp-2 cells was evaluated as a measure of cytotoxicity, averaging 7.46%. Strain CF74 induced the highest level of LDH, 24.3%, and caused >50% cell rounding, detachment, and death. We named strain CF74 “cytotoxic and aggregative C. freundii.” Genome sequencing of CF74 revealed that it had acquired 7 genomic islands, including 2 fimbriae islands and a type VI secretion system island, all of which are potential virulence factors. Our results show that aggregative adherence and cytotoxicity play an important role in the pathogenesis of C. freundii

    Design and Implementation of DDC Based on Walsh Transform for HF Radar Receiver

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    Finite element analysis of individualized magnesium alloy meshes with different thickness

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    Objective To investigate the stress-strain distribution of magnesium alloy meshes with different thickness during bone healing by three-dimensional finite element analysis in order to provide a reference for the design of personalized magnesium alloy mesh. Methods After the cone-beam computed tomography (CBCT) data of a patient with tooth loss of C2-D2 and large alveolar defect were extracted, three-dimensional reconstruction was performed on the bone defect area. Three-dimensional finite element models of bone implant material and magnesium alloy meshes with different thickness were designed, and their stress-strain distributions were analyzed. Results The strain and stress showed a decreasing trend with the increase of the thickness of magnesium alloy mesh. During the process of bone healing, the stress of the bone implant material was gradually increased while the strain was gradually decreased. The strain of immature and mature bone was less than the strain at break. The stress was decreased first and then increased in the degradation of magnesium alloy mesh. Conclusion Magnesium alloy mesh of 0.3 and 0.4 mm thickness can only bear a small load, and can't meet the need of large area guided bone regeneration (GBR). The maximum equivalent stress of 0.5 mm-thickness magnesium alloy mesh is within the safe range, and the mesh has enough strength in the process of degradation, and can guide good bone healing and meet the clinical needs of GBR

    An Optical Acoustic Detection System Based on Fabry Pérot Etalon Stability Structure

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    The optical acoustic detection system based on the Fabry Pérot Etalon (FPE) with high quality–factor (High Q) and stability structure is described and tested. The FPE contains two high–reflectivity Plano–Concave lenses, achieving high fineness and stability. The protective structure of the confocal stabilized FPE is composed of an invar tube, copper sheath, Bakelite sheath and aluminum housing to protect the sensor from the effects of ambient temperature and vibration. The audio signal is injected into the cavity through the sound hole located in the center of the cavity. Acoustic waves induce the vibration of the medium in the cavity, which leads to a simultaneous change in the FPE optical path and a shift of the interference spectrum. The acoustic detection system is built, and the frequency of the laser is locked on the resonant frequency points of the FPE by using phase modulation technology, so as to detect acoustic signals of different frequencies and amplitudes. In addition, the sensitivity of the proposed sensor exceeds 34.49 mV/Pa in the range of 20 Hz–20 kHz. A Signal-to-Noise Ratio (SNR) of 37 dB can be achieved at 20 Hz. Acoustic signal detection technology based on the FPE stability model is used to test the theoretical feasibility of the future high sensitivity Fabry Pérot Interferometric (FPI) acoustic sensors

    A “Turn-On” Fluorescence Copper Biosensor Based on DNA Cleavage-Dependent Graphene Oxide-dsDNA-CdTe Quantum Dots Complex

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    A novel “turn-on” fluorescent copper biosensor is developed successfully based on the graphene oxide (GO)-dsDNA-CdTe quantum dots (QDs) complex via chemical crosslink method. The optical and structure properties of GO-dsDNA-CdTe QDs complex are studied by fluorescence (FL) spectra and transmission electron microscopy (TEM) in detail. It is demonstrated that the fluorescence quenching of CdTe QDs is a process of fluorescence resonance energy transfer (FRET) due to the essential surface and quenching properties of two-dimensional GO. Copper ions induce the catalytic reaction of DNA chain and irreversibly break at the cleavage site, which will cause the G-quadruplex formation, moreover further result in the CdTe QDs separated from GO and restored its fluorescence. Therefore, a significant recovery effect on the fluorescence of the GO-dsDNA-CdTe QDs complex is observed in the presence of copper ions. The fluorescence responses are concentration-dependent and can be well described by a linear equation. Compared with other metal ions, the sensor performs good selectivity for copper ions
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