The high turbulence of unstable combustion in the working process of liquid rocket engine will cause periodic pressure pulsation.Therefore,a pressure pulsation device that is easy to reuse,broadband,suited for poisono...The high turbulence of unstable combustion in the working process of liquid rocket engine will cause periodic pressure pulsation.Therefore,a pressure pulsation device that is easy to reuse,broadband,suited for poisonous media,and high pressure is designed and produced.Numerical and experimental studies show that the pulsator produces stable pressure waveforms at different flow rates,pressures,and frequencies,while the pressure waveform amplitude at the excitation frequency is larger.The pressure waveform amplitude increases exponentially with the flow rate and with smaller gaps and linear pressure increasing.The pressure waveform amplitude varies greatly at different frequencies along the pipeline.As the frequency increases,the pressure waveform amplitude of the excitation increases first and then decreases.The pressure waveform amplitude at low frequencies changes little along the pipeline.The pressure waveform amplitude at medium frequencies readily couples to the pipeline flow field and increases its value.The pressure waveform amplitude at high frequencies attenuates along the pipeline,where attenuation increases with frequency.The ability of the pulsator to provide stable excitation and high pressure is verified through normal and high pressure testsindifferentpipelinesystems.展开更多
The gating system and the overflow system were designed according to the casting structure during high pressure die casting(HPDC) process. The simulation was carried out by ProCAST software to visualize the injection ...The gating system and the overflow system were designed according to the casting structure during high pressure die casting(HPDC) process. The simulation was carried out by ProCAST software to visualize the injection chamber pre-crystallization and the flow of molten metal. The main work is to research four die casting process parameters, i.e. injection temperature, low-pressure velocity, high-and low-pressure velocity’s switching position, and high-pressure velocity. Experimental results show that the higher injection temperature and lowpressure velocity can mitigate the pre-crystallization of the injection chamber. However, when the low-pressure velocity exceeds 0.2 m·s-1, the air entrapment in the chamber occurs. Besides, when the high-pressure velocity is greater than 2.5 m·s-1, the overflow channel at the final filling position is covered by the liquid metal too early. Finally, the injection temperature of 650 °C, the low-pressure velocity of 0.2 m·s-1, the high-and low-pressure velocity’s switching position of 320 mm and the high-pressure velocity of 2 m·s-1 are obtained as the optimal parameters by the software simulation, which has been verified by actual production.展开更多
Background:Lactic acid bacteria(LAB)participating in milk fermentation naturally release and enrich the fermented dairy product with a broad range of bioactive metabolites,which has numerous roles in the intestinal he...Background:Lactic acid bacteria(LAB)participating in milk fermentation naturally release and enrich the fermented dairy product with a broad range of bioactive metabolites,which has numerous roles in the intestinal health-promot-ing of the consumer.However,information is lacking regarding the application prospect of LAB fermented milk in the animal industry.This study investigated the effects of lactic acid bacteria-fermented formula milk(LFM)on the growth performance,intestinal immunity,microbiota composition,and transcriptomic responses in weaned piglets.A total of 24 male weaned piglets were randomly divided into the control(CON)and LFM groups.Each group consisted of 6 replicates(cages)with 2 piglets per cage.Each piglet in the LFM group were supplemented with 80 mL LFM three times a day,while the CON group was treated with the same amount of drinking water.Results:LFM significantly increased the average daily gain of piglets over the entire 14 d(P<0.01)and the average daily feed intake from 7 to 14 d(P<0.05).Compared to the CON group,ileal goblet cell count,villus-crypt ratio,sIgA,and lactate concentrations in the LFM group were significantly increased(P<0.05).Transcriptomic analysis of ileal mucosa identified 487 differentially expressed genes(DEGs)between two groups.Especially,DEGs involved in the intestinal immune network for IgA production pathways,such as polymeric immunoglobulin receptor(PIGR),were significantly up-regulated(P<0.01)by LFM supplementation.Moreover,trefoil factor 2(TFF2)in the LFM group,one of the DEGs involved in the secretory function of goblet cells,was also significantly up-regulated(P<0.01).Sequenc-ing of the 16S rRNA gene of microbiota demonstrated that LFM led to selective enrichment of lactate-producing and short-chain fatty acid(SCFA)-producing bacteria in the ileum,such as an increase in the relative abundance of Entero-coccus(P=0.09)and Acetitomaculum(P<0.05).Conclusions:LFM can improve intestinal health and immune tolerance,thus enhancing the growth performance of weaned piglets.The changes in microbiota and metabolites induced by LFM might mediate the regulation of the secretory function of goblet cells.展开更多
Backgroud: This study aimed to determine the effects of early antibiotic intervention(EAI) on subsequent blood parameters, apparent nutrient digestibility, and fecal fermentation profile in pigs with different diet...Backgroud: This study aimed to determine the effects of early antibiotic intervention(EAI) on subsequent blood parameters, apparent nutrient digestibility, and fecal fermentation profile in pigs with different dietary crude protein(CP) levels. Eighteen litters of piglets(total 212) were randomly allocated to 2 groups and were fed a creep feed diet with or without in-feed antibiotics(olaquindox, oxytetracycline calcium and kitasamycin) from postnatal d 7 to d 42. On d 42, the piglets within the control or antibiotic group were mixed, respectively, and then further randomly assigned to a normal-(20%, 18%, and 14% CP from d 42 to d 77, d 77 to d 120, and d 120 to d 185,respectively) or a low-CP diet(16%, 14%, and 10% CP from d 42 to d 77, d 77 to d 120, and d 120 to d 185,respectively), generating 4 groups. On d 77(short-term) and d 185(long-term), serum and fecal samples were obtained for blood parameters, microbial composition and microbial metabolism analysis.Results: EAI increased(P 〈 0.05) albumin and glucose concentrations in low-CP diet on d 77, and increased(P 〈 0.05) urea concentration in normal-CP diet. On d 185, EAI increased(P 〈 0.05) globulin concentration in normal-CP diets, but decreased glucose concentration. For nutrient digestibility, EAI increased(P 〈 0.05)digestibility of CP on d 77. For fecal microbiota, the EAI as well as low-CP diet decreased(P 〈 0.05) E. coli count on d 77. For fecal metabolites, on d 77, EAI decreased(P 〈 0.05) total amines concentration but increased skatole concentration in low-CP diet. On d 185, the EAI increased(P 〈 0.05) putrescine and total amines concentrations in low-CP diets but reduced(P 〈 0.05) in the normal-CP diets. The low-CP diet decreased the concentrations of these compounds.Conclusions: Collectively, these results indicate that EAI has short-term effects on the blood parameters and fecal microbial fermentation profile. The effects of EAI varied between CP levels, which was characterized by the significant alteration of glucose and putrescine concentration.展开更多
The dynamic soft sensor based on a single Gaussian process regression(GPR) model has been developed in fermentation processes.However,limitations of single regression models,for multiphase/multimode fermentation proce...The dynamic soft sensor based on a single Gaussian process regression(GPR) model has been developed in fermentation processes.However,limitations of single regression models,for multiphase/multimode fermentation processes,may result in large prediction errors and complexity of the soft sensor.Therefore,a dynamic soft sensor based on Gaussian mixture regression(GMR) was proposed to overcome the problems.Two structure parameters,the number of Gaussian components and the order of the model,are crucial to the soft sensor model.To achieve a simple and effective soft sensor,an iterative strategy was proposed to optimize the two structure parameters synchronously.For the aim of comparisons,the proposed dynamic GMR soft sensor and the existing dynamic GPR soft sensor were both investigated to estimate biomass concentration in a Penicillin simulation process and an industrial Erythromycin fermentation process.Results show that the proposed dynamic GMR soft sensor has higher prediction accuracy and is more suitable for dynamic multiphase/multimode fermentation processes.展开更多
The effects of rare earth elements(La,Sm)on the high-temperature(250℃)microstructure and mechanical properties of Al-Si-Cu alloys were analyzed.The experimental results show that with the addition of La and Sm,theα-...The effects of rare earth elements(La,Sm)on the high-temperature(250℃)microstructure and mechanical properties of Al-Si-Cu alloys were analyzed.The experimental results show that with the addition of La and Sm,theα-Al was significantly refined,and the eutectic Si changed from acicular to rod-like and granular.XRD and SEM analysis shows that the rare earth phases in the alloy were mainly AlSiRe and AlRe.Fracture morphology observations show the fracture mode of the alloy changes from brittle and ductile fracture to ductile fracture.With the increase of La or Sm contents,the mechanical properties of the alloys at 250℃ increase at first,and then decrease.When the contents of La and Sm are 0.4wt.%and 0.2wt.%,the tensile strength of the alloy reaches maximum of 143.91 MPa and 201.48 MPa,respectively.展开更多
Single-crystalline Ga-doped SnO2 nanowires and SnO2:Ga2O3 heterogeneous microcombs were synthesized by a simple one-step thermal evaporation and condensation method. They were characterized by means of X-ray powder d...Single-crystalline Ga-doped SnO2 nanowires and SnO2:Ga2O3 heterogeneous microcombs were synthesized by a simple one-step thermal evaporation and condensation method. They were characterized by means of X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). FE-SEM images showed that the products consisted of nanowires and mierocombs that represent a novel morphology. XRD, SAED and EDS indicated that they were single-crystalline tetragonal SnO2. The influence of experimental conditions on the morphologies of the products is discussed. The morphology of the product showed a ribbon-like stem and nanoribbon array aligned evenly along one or both side of the nanoribbon. It was found that many Ga2O3 nanoparticles deposited on the surface of the microcombs. The major core nanoribbon grew mainly along the [110] direction and the self-organized branching nanoribbons grew epitaxially along [110] or [110] orientation from the (110) plane of the stem. A growth process was proposed for interpreting the growth of these remarkable SnO2:Ga2O3 heterogeneous microcombs. Due to the heavy doping of Ga, the emission peak in photoluminescence spectra has red-shifted as well as broadened significantly.展开更多
Understanding alkali metal ions’(e.g.,Li^(+)/Na^(+)/K^(+))transport mechanism is challenging but critical to improving the performance of alkali metal batteries.Herein using a-MnO_(2)nanowires as cathodes,the transpo...Understanding alkali metal ions’(e.g.,Li^(+)/Na^(+)/K^(+))transport mechanism is challenging but critical to improving the performance of alkali metal batteries.Herein using a-MnO_(2)nanowires as cathodes,the transport kinetics of Li^(+)/Na^(+)/K^(+)in the 2×2 channels of a-MnO_(2)with a growth direction of[001]is revealed.We show that ion radius plays a decisive role in determining the ion transport and electrochemistry.Regardless of the ion radii,Li^(+)/Na^(+)/K^(+)can all go through the 2×2 channels of a-MnO_(2),generating large stress and causing channel merging or opening.However,smaller ions such as Li^(+)and Na^(+)cannot only transport along the[001]direction but also migrate along the<110>direction to the nanowire surface;for large ion such as K^(+),diffusion along the<110>direction is prohibited.The different ion transport behavior has grand consequences in the electrochemistry of metal oxygen batteries(MOBs).For Li-O_(2)battery,Li^(+)transports uniformly to the nanowire surface,forming a uniform layer of oxide;Na^(+)also transports to the nanowire surface but may be clogged locally due to its larger radius,therefore sporadic pearl-like oxides form on the nanowire surface;K^(+)cannot transport to the nanowire surface due to its large radius,instead,it breaks the nanowire locally,causing local deposition of potassium oxides.The study provides atomic scale understanding of the alkali metal ion transport mechanism which may be harnessed to improve the performance of MOBs.展开更多
Background Serotonin is an important signaling molecule that regulates secretory and sensory functions in the gut.Gut microbiota has been demonstrated to affect serotonin synthesis in rodent models.However,how gut mic...Background Serotonin is an important signaling molecule that regulates secretory and sensory functions in the gut.Gut microbiota has been demonstrated to affect serotonin synthesis in rodent models.However,how gut microbes regulate intestinal serotonin production in piglets remains vague.To investigate the relationship between microbiota and serotonin specifically in the colon,microbial composition and serotonin concentration were analyzed in ileum-cannulated piglets subjected to antibiotic infusion from the ileum when comparing with saline infusion.Microbes that correlated positively with serotonin production were isolated from piglet colon and were further used to investi-gate the regulation mechanisms on serotonin production in IPEC-J2 and a putative enterochromaffin cell line RIN-14B cells.Results Antibiotic infusion increased quantities of Lactobacillus amylovorus(LA)that positively correlated with increased serotonin concentrations in the colon,while no effects observed for Limosilactobacillus reuteri(LR).To understand how microbes regulate serotonin,representative strains of LA,LR,and Streptococcus alactolyticus(SA,enriched in feces from prior observation)were selected for cell culture studies.Compared to the control group,LA,LR and SA supernatants significantly up-regulated tryptophan hydroxylase 1(TPH1)expression and promoted serotonin production in IPEC-J2 cells,while in RIN-14B cells only LA exerted similar action.To investigate potential mechanisms mediated by microbe-derived molecules,microbial metabolites including lactate,acetate,glutamine,andγ-aminobutyric acid were selected for cell treatment based on computational and metabolite profiling in bacte-rial supernatant.Among these metabolites,acetate upregulated the expression of free fatty acid receptor 3 and TPH1 while downregulated indoleamine 2,3-dioxygenase 1.Similar effects were also recapitulated when treating the cells with AR420626,an agonist targeting free fatty acid receptor 3.Conclusions Overall,these results suggest that Lactobacillus amylovorus showed a positive correlation with sero-tonin production in the pig gut and exhibited a remarkable ability to regulate serotonin production in cell cultures.These findings provide evidence that microbial metabolites mediate the dialogue between microbes and host,which reveals a potential approach using microbial manipulation to regulate intestinal serotonin biosynthesis.展开更多
Nano-floating gate memory devices with ZnO nano-crystals as charge storage layers are fabricated,and the influence of post-deposition annealing temperature and thickness of the ZnO layer are investigated.Atomic force ...Nano-floating gate memory devices with ZnO nano-crystals as charge storage layers are fabricated,and the influence of post-deposition annealing temperature and thickness of the ZnO layer are investigated.Atomic force microscopy and scanning electron microscopy reveal the morphology of discrete ZnO nano-crystals.For capacitance-voltage measurements,it is found that the memory device with 1.5 nm ZnO and annealed at 700℃shows a larger memory window of 4.3 V(at±6 V)and better retention characteristics than memoriy devices with2.5 nm ZnO or annealed at other temperatures.These results indicate that the nano-floating gate memory with ZnO nano-crystals can obtain good trade-off memory properties.展开更多
High-speed target three-dimensional[3D]trajectory and velocity measurement methods have important uses in many fields,including explosive debris and rotating specimen trajectory tracking.The conventional approach uses...High-speed target three-dimensional[3D]trajectory and velocity measurement methods have important uses in many fields,including explosive debris and rotating specimen trajectory tracking.The conventional approach uses a binocular system with two high-speed cameras to capture the target’s 3D motion information.Hardware cost for the conventional approach is high,and accurately triggering several high-speed cameras is difficult.Event-based cameras have recently received considerable attention due to advantages in dynamic range,temporal resolution,and power consumption.To address problems of camera synchronization difficulties,data redundancy,and motion blur in high-speed target 3D trajectory measurement,this Letter proposes a 3D trajectory measurement method based on a single-event camera and a four-mirror adaptor.The 3D trajectory and velocity of a particle flight process and a marker on a rotating disc were measured with the proposed method,and the results show that the proposed method can monitor the operational state of high-speed flying and rotating objects at a very low hardware cost.展开更多
The widespread applications of lithium-ion batteries(LIBs)generate tons of spent LIBs.Therefore,recycling LIBs is of paramount importance in protecting the environment and saving the resources.Current commercialized L...The widespread applications of lithium-ion batteries(LIBs)generate tons of spent LIBs.Therefore,recycling LIBs is of paramount importance in protecting the environment and saving the resources.Current commercialized LIBs mostly adopt layered oxides such as LiCoO_(2)(LCO)or LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(NMC)as the cathode materials.Converting the intercalation-type spent oxides into conversion-type cathodes(such as metal fluorides(MFs))offers a valid recycling strategy and provides substantially improved energy densities for LIBs.Herein,two typical Co-based cathodes,LCO and LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NMC622),in spent LIBs were successfully converted to CoF_(2) and(Ni_(x)Co_(y)Mn_(z))F_(2) cathodes by a reduction and fluorination technique.The as converted CoF_(2) and(Ni_(x)Co_(y)Mn_(z))F_(2) delivered cell energy densities of 650 and 700 Wh/kg,respectively.Advanced atomic-level electron microscopy revealed that the used LCO and NMC622 were converted to highly phase pure Co metal and Ni_(0.6)Co_(0.2)Mn_(0.2) alloys in the used graphite-assisted reduction roasting,simultaneously producing the important product of Li_(2)CO_(3) using only environment friendly solvent.Our study provided a versatile strategy to convert the intercalation-type Co-based cathode in the spent LIBs into conversion-type MFs cathodes,which offers a new avenue to recycle the spent LIBs and substantially increase the energy densities of next generation LIBs.展开更多
Gut microbiota is generally recognized to play a crucial role in maintaining host health and metabolism.The correlation among gut microbiota,glycolipid metabolism,and metabolic diseases has been well reviewed in human...Gut microbiota is generally recognized to play a crucial role in maintaining host health and metabolism.The correlation among gut microbiota,glycolipid metabolism,and metabolic diseases has been well reviewed in humans.However,the interplay between gut microbiota and host metabolism in swine remains incompletely understood.Given the limitation in conducting human experiments and the high similarity between swine and humans in terms of anatomy,physiology,polyphagy,habits,and metabolism and in terms of the composition of gut microbiota,there is a pressing need to summarize the knowledge gained regarding swine gut microbiota,its interplay with host metabolism,and the underlying mechanisms.This review aimed to outline the bidirectional regulation between gut microbiota and nutrient metabolism in swine and to emphasize the action mechanisms underlying the complex microbiomeehost crosstalk via the gut microbiotaegutebrain axis.Moreover,it highlights the new advances in knowledge of the diurnal rhythmicity of gut microbiota.A better understanding of these aspects can not only shed light on healthy and efficient pork production but also promote our knowledge on the associations between gut microbiota and the microbiomeehost crosstalk mechanism.More importantly,knowledge on microbiota,host health and metabolism facilitates the development of a precise intervention therapy targeting the gut microbiota.展开更多
The tensile creep behavior of extruded Mg-6 Gd alloy,having the tensile yield strength of~ 110 MPa at 175 ℃,has been investigated under 175 ℃ and 150 MPa. In this study, the extruded Mg-6 Gd sample exhibits the tot...The tensile creep behavior of extruded Mg-6 Gd alloy,having the tensile yield strength of~ 110 MPa at 175 ℃,has been investigated under 175 ℃ and 150 MPa. In this study, the extruded Mg-6 Gd sample exhibits the total tensile strain of ~10.5% after the creep time of 1100 h,and the fast plastic strain of ~4.6% at the beginning of the creep test. The microstructure result suggests that the dislocation deformation is the main deformation mode during creep, and the grains with orientation close to(0001) II ED disappear after creep. The creep process containing a low creep strain has no effective promotion for the precipitation compared with the aging process without strain. The origination of creep crack is related to the formation of precipitate-free zone during creep. The work offers an important implication to research the microstructure evolution under an applied stress in a weak aging response Mg alloy.展开更多
The mechanical force between cells and the extracellular microenvironment is crucial to many physiological processes such as cancer metastasis and stem cell differentiation. Mitosis plays an essential role in all thes...The mechanical force between cells and the extracellular microenvironment is crucial to many physiological processes such as cancer metastasis and stem cell differentiation. Mitosis plays an essential role in all these processes and thus an in-depth understanding of forces during mitosis gains insight into disease diagnosis and disease treatment. Here, we develop a traction force microscope method based on monolayer fluorescent beads for measuring the weak traction force (tens of Pa) of mitotic cells in three dimensions. We quantify traction forces of human ovarian granulosa (KGN) cells exerted on the extracellular matrix throughout the entire cell cycle in three dimensions. Our measurements reveal how forces vary during the cell cycle, especially during cell division. Furthermore, we study the effect of paclitaxel (PTX) and nocodazole (NDZ) on mitotic KGN cells through the measurement of traction forces. Our results show that mitotic cells with high concentrations of PTX exert a larger force than those with high concentrations of NDZ, which proved to be caused by changes in the structure and number of microtubules. These findings reveal the key functions of microtubule in generating traction forces during cell mitosis and explain how dividing cells regulate themselves in response to anti-mitosis drugs. This work provides a powerful tool for investigating cell-matrix interactions during mitosis and may offer a potential way to new therapies for cancer.展开更多
Dear Editor,Intensity-modulated radiotherapy(IMRT)has a distinct advantage of high conformity and is an appropriate tech-nique for treating nasopharyngeal carcinoma(NPC).Pre-vious studies have demonstrated that anatom...Dear Editor,Intensity-modulated radiotherapy(IMRT)has a distinct advantage of high conformity and is an appropriate tech-nique for treating nasopharyngeal carcinoma(NPC).Pre-vious studies have demonstrated that anatomical changes in the external contour,shape,and location of the target and critical structures are significant and result in dosi-metric changes[1,2].Patients’quality of life and clini-cal outcomes might be improved by IMRT replanning[3].Therefore,replanning strategies should be consid-ered instead of single-planning strategies throughout the entire course of radiotherapy.However,there are sub-stantial controversies on(1)the appropriate time for tar-get redelineation,(2)how to modify the target volumes,and(3)how to evaluate the modified plans.The present study provides a new perspective in replanning with regard to these three aspects.展开更多
The operational numerical weather prediction system established by the China Meteorological Administration(CMA),based on the Global/Regional Assimilation and Prediction System(GRAPES)model,adopts the classical semi-im...The operational numerical weather prediction system established by the China Meteorological Administration(CMA),based on the Global/Regional Assimilation and Prediction System(GRAPES)model,adopts the classical semi-implicit semi-Lagrangian(SISL)time integration algorithm.This paper describes a major upgrade to the dynamical core of the CMA global forecast system(CMA-GFS),which was successfully incorporated into operation in 2020.In the upgrade,the classical SISL is further developed into a predictor–corrector scheme,a three-dimensional(3D)reference profile instead of the original isothermal reference profile is applied when implementing the semi-implicit algorithm,and a hybrid terrain-following vertical coordinate system is also applied.The new version of the dynamical core greatly improves the model performance,the time integration reaches second-order accuracy,the time step can be extended by 50%,and the efficiency is greatly improved(by approximately 30%).Atmospheric circulation simulation is systematically improved,and deviations in temperature,wind,and humidity are reduced.The new version of the dynamical core provides a solid foundation for further development of the entire operational system of the CMA.展开更多
Short-chain fatty acids(SCFA)can regulate appetite by stimulating the secretion of satiety hormones.However,the impact of short-chain fatty acid propionate on the release of gut satiety hormones and appetite regulatio...Short-chain fatty acids(SCFA)can regulate appetite by stimulating the secretion of satiety hormones.However,the impact of short-chain fatty acid propionate on the release of gut satiety hormones and appetite regulation in pigs is not completely understood.In this study,16 pigs were infused with saline or sodium propionate through a fistula in the caecum during a 28-day experimental period.We characterized the effects of propionate administration on peptide YY(PYY)and glucagon-like peptide 1(GLP-1)secretion from colonic tissue,and investigated the role of propionate infusion on the expression of appetite-related genes in the colon and hypothalamus.Further,the direct impact of propionate administration on the expression of orexigenic neuropeptide agouti-related protein(AgRP)in hypothalamic N38 cells was also examined.The results showed that intra-cecal infusion of propionate reduced the short-term feed intake(P<0.05)but not the long-term feed intake in pigs(P>0.05).Propionate administration stimulated PYY and GLP-1 release from colon tissue in vivo and ex vivo(P<0.05).It also upregulated PYY expression in the colonic mucosa(P<0.05).Meanwhile,the GLP-1 and PYY levels in the blood were increased after intra-cecal infusion of propionate at d 28(P<0.05).Additionally,intra-cecal infusion of propionate upregulated the mRNA and protein expression of free fatty acid receptor 2/3(FFAR2/FFAR3)in the colonic mucosa(P<0.05).Propionate infusion also downregulated the orexigenic AgRP mRNA expression(P<0.05)and upregulated the anorexigenic cocaine-and amphetamine-regulated transcript(CART)mRNA expression(P=0.09)in the hypothalamus.Moreover,propionate administration directly downregulated AgRP expression in hypothalamic N38 cells in a dose-dependent manner(P<0.05).Collectively,these findings demonstrated that cecal propionate stimulated colonic secretion of satiety hormones and suppressed appetite to reduce the short-term feed intake in pigs.This study highlights that microbial-derived propionate exerts an important role in regulating the physical functions of the host.展开更多
Objective:The current meta-analysis determined the relevance of HLA-DRB1 gene polymor-phisms in a Chinese population with pulmonary tuberculosis.Methods:The CBM,CNKI,and MEDLINE databases were retrieved by computers.D...Objective:The current meta-analysis determined the relevance of HLA-DRB1 gene polymor-phisms in a Chinese population with pulmonary tuberculosis.Methods:The CBM,CNKI,and MEDLINE databases were retrieved by computers.Domes-tic and international documents involving studies on the relevance of HLA-DRB1 gene polymor-phisms in a Chinese population with pulmonary tuberculosis were collected from the database until May 2013,and statistical analysis was performed on all of the eligible results with RevMan5.0 software.Results:Eleven case-control studies were collected,including 1364 cases in the pulmonary tuberculosis group and 1496 cases in the control group.The consolidated OR values and 95%confidence intervals of the case and control groups of HLA-DRB1*04,HLA-DRB1*15,and HLA-DRB1*16 were 1.32(1.09-1.60),1.40(1.01-1.93),and 1.36(1.01-1.83),respectively.Conclusion:HLA-DRB1*04,HLA-DRB1*15,and HLA-DRB1*16 may be susceptibility genes for pulmonary tuberculosis in a Chinese population.展开更多
基金National Science and Technology Major Projects(2017-V-0012-0064)。
文摘The high turbulence of unstable combustion in the working process of liquid rocket engine will cause periodic pressure pulsation.Therefore,a pressure pulsation device that is easy to reuse,broadband,suited for poisonous media,and high pressure is designed and produced.Numerical and experimental studies show that the pulsator produces stable pressure waveforms at different flow rates,pressures,and frequencies,while the pressure waveform amplitude at the excitation frequency is larger.The pressure waveform amplitude increases exponentially with the flow rate and with smaller gaps and linear pressure increasing.The pressure waveform amplitude varies greatly at different frequencies along the pipeline.As the frequency increases,the pressure waveform amplitude of the excitation increases first and then decreases.The pressure waveform amplitude at low frequencies changes little along the pipeline.The pressure waveform amplitude at medium frequencies readily couples to the pipeline flow field and increases its value.The pressure waveform amplitude at high frequencies attenuates along the pipeline,where attenuation increases with frequency.The ability of the pulsator to provide stable excitation and high pressure is verified through normal and high pressure testsindifferentpipelinesystems.
基金financially supported by the National Key Research and Development Program of China(No.2016YFB0301003)
文摘The gating system and the overflow system were designed according to the casting structure during high pressure die casting(HPDC) process. The simulation was carried out by ProCAST software to visualize the injection chamber pre-crystallization and the flow of molten metal. The main work is to research four die casting process parameters, i.e. injection temperature, low-pressure velocity, high-and low-pressure velocity’s switching position, and high-pressure velocity. Experimental results show that the higher injection temperature and lowpressure velocity can mitigate the pre-crystallization of the injection chamber. However, when the low-pressure velocity exceeds 0.2 m·s-1, the air entrapment in the chamber occurs. Besides, when the high-pressure velocity is greater than 2.5 m·s-1, the overflow channel at the final filling position is covered by the liquid metal too early. Finally, the injection temperature of 650 °C, the low-pressure velocity of 0.2 m·s-1, the high-and low-pressure velocity’s switching position of 320 mm and the high-pressure velocity of 2 m·s-1 are obtained as the optimal parameters by the software simulation, which has been verified by actual production.
基金supported by the National Natural Science Foundation of China(31872362 and 32072688)the Agricultural Science and Technology Independent Innovation Fund Project of Jiangsu Province[CX(19)1006].
文摘Background:Lactic acid bacteria(LAB)participating in milk fermentation naturally release and enrich the fermented dairy product with a broad range of bioactive metabolites,which has numerous roles in the intestinal health-promot-ing of the consumer.However,information is lacking regarding the application prospect of LAB fermented milk in the animal industry.This study investigated the effects of lactic acid bacteria-fermented formula milk(LFM)on the growth performance,intestinal immunity,microbiota composition,and transcriptomic responses in weaned piglets.A total of 24 male weaned piglets were randomly divided into the control(CON)and LFM groups.Each group consisted of 6 replicates(cages)with 2 piglets per cage.Each piglet in the LFM group were supplemented with 80 mL LFM three times a day,while the CON group was treated with the same amount of drinking water.Results:LFM significantly increased the average daily gain of piglets over the entire 14 d(P<0.01)and the average daily feed intake from 7 to 14 d(P<0.05).Compared to the CON group,ileal goblet cell count,villus-crypt ratio,sIgA,and lactate concentrations in the LFM group were significantly increased(P<0.05).Transcriptomic analysis of ileal mucosa identified 487 differentially expressed genes(DEGs)between two groups.Especially,DEGs involved in the intestinal immune network for IgA production pathways,such as polymeric immunoglobulin receptor(PIGR),were significantly up-regulated(P<0.01)by LFM supplementation.Moreover,trefoil factor 2(TFF2)in the LFM group,one of the DEGs involved in the secretory function of goblet cells,was also significantly up-regulated(P<0.01).Sequenc-ing of the 16S rRNA gene of microbiota demonstrated that LFM led to selective enrichment of lactate-producing and short-chain fatty acid(SCFA)-producing bacteria in the ileum,such as an increase in the relative abundance of Entero-coccus(P=0.09)and Acetitomaculum(P<0.05).Conclusions:LFM can improve intestinal health and immune tolerance,thus enhancing the growth performance of weaned piglets.The changes in microbiota and metabolites induced by LFM might mediate the regulation of the secretory function of goblet cells.
基金supported by National Key Basic Research Program of China(2013CB127300)Natural Science Foundation of China(31430082)
文摘Backgroud: This study aimed to determine the effects of early antibiotic intervention(EAI) on subsequent blood parameters, apparent nutrient digestibility, and fecal fermentation profile in pigs with different dietary crude protein(CP) levels. Eighteen litters of piglets(total 212) were randomly allocated to 2 groups and were fed a creep feed diet with or without in-feed antibiotics(olaquindox, oxytetracycline calcium and kitasamycin) from postnatal d 7 to d 42. On d 42, the piglets within the control or antibiotic group were mixed, respectively, and then further randomly assigned to a normal-(20%, 18%, and 14% CP from d 42 to d 77, d 77 to d 120, and d 120 to d 185,respectively) or a low-CP diet(16%, 14%, and 10% CP from d 42 to d 77, d 77 to d 120, and d 120 to d 185,respectively), generating 4 groups. On d 77(short-term) and d 185(long-term), serum and fecal samples were obtained for blood parameters, microbial composition and microbial metabolism analysis.Results: EAI increased(P 〈 0.05) albumin and glucose concentrations in low-CP diet on d 77, and increased(P 〈 0.05) urea concentration in normal-CP diet. On d 185, EAI increased(P 〈 0.05) globulin concentration in normal-CP diets, but decreased glucose concentration. For nutrient digestibility, EAI increased(P 〈 0.05)digestibility of CP on d 77. For fecal microbiota, the EAI as well as low-CP diet decreased(P 〈 0.05) E. coli count on d 77. For fecal metabolites, on d 77, EAI decreased(P 〈 0.05) total amines concentration but increased skatole concentration in low-CP diet. On d 185, the EAI increased(P 〈 0.05) putrescine and total amines concentrations in low-CP diets but reduced(P 〈 0.05) in the normal-CP diets. The low-CP diet decreased the concentrations of these compounds.Conclusions: Collectively, these results indicate that EAI has short-term effects on the blood parameters and fecal microbial fermentation profile. The effects of EAI varied between CP levels, which was characterized by the significant alteration of glucose and putrescine concentration.
基金Supported by the Natural Science Foundation of Jiangsu Province of China(BK20130531)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD[2011]6)Jiangsu Government Scholarship
文摘The dynamic soft sensor based on a single Gaussian process regression(GPR) model has been developed in fermentation processes.However,limitations of single regression models,for multiphase/multimode fermentation processes,may result in large prediction errors and complexity of the soft sensor.Therefore,a dynamic soft sensor based on Gaussian mixture regression(GMR) was proposed to overcome the problems.Two structure parameters,the number of Gaussian components and the order of the model,are crucial to the soft sensor model.To achieve a simple and effective soft sensor,an iterative strategy was proposed to optimize the two structure parameters synchronously.For the aim of comparisons,the proposed dynamic GMR soft sensor and the existing dynamic GPR soft sensor were both investigated to estimate biomass concentration in a Penicillin simulation process and an industrial Erythromycin fermentation process.Results show that the proposed dynamic GMR soft sensor has higher prediction accuracy and is more suitable for dynamic multiphase/multimode fermentation processes.
基金the National Key Research and Development Program of China(No.2016YFB0301003)。
文摘The effects of rare earth elements(La,Sm)on the high-temperature(250℃)microstructure and mechanical properties of Al-Si-Cu alloys were analyzed.The experimental results show that with the addition of La and Sm,theα-Al was significantly refined,and the eutectic Si changed from acicular to rod-like and granular.XRD and SEM analysis shows that the rare earth phases in the alloy were mainly AlSiRe and AlRe.Fracture morphology observations show the fracture mode of the alloy changes from brittle and ductile fracture to ductile fracture.With the increase of La or Sm contents,the mechanical properties of the alloys at 250℃ increase at first,and then decrease.When the contents of La and Sm are 0.4wt.%and 0.2wt.%,the tensile strength of the alloy reaches maximum of 143.91 MPa and 201.48 MPa,respectively.
基金This work was supported by the National Natural Science Foundation of China (No.20671027), and the Natural Science Foundation of Anhui province, China (No.050440904).
文摘Single-crystalline Ga-doped SnO2 nanowires and SnO2:Ga2O3 heterogeneous microcombs were synthesized by a simple one-step thermal evaporation and condensation method. They were characterized by means of X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and selected-area electron diffraction (SAED). FE-SEM images showed that the products consisted of nanowires and mierocombs that represent a novel morphology. XRD, SAED and EDS indicated that they were single-crystalline tetragonal SnO2. The influence of experimental conditions on the morphologies of the products is discussed. The morphology of the product showed a ribbon-like stem and nanoribbon array aligned evenly along one or both side of the nanoribbon. It was found that many Ga2O3 nanoparticles deposited on the surface of the microcombs. The major core nanoribbon grew mainly along the [110] direction and the self-organized branching nanoribbons grew epitaxially along [110] or [110] orientation from the (110) plane of the stem. A growth process was proposed for interpreting the growth of these remarkable SnO2:Ga2O3 heterogeneous microcombs. Due to the heavy doping of Ga, the emission peak in photoluminescence spectra has red-shifted as well as broadened significantly.
基金financially supported by the National Natural Science Foundation of China(22279112,52022088,51971245,51772262,21406191,U20A20336,21935009)the Natural Science Foundation of Hebei Province,China(B2022203018,F2021203097,B2020203037,B2018203297)+2 种基金the Hunan Innovation Team,China(2018RS3091)the Beijing Natural Science Foundation,China(2202046)the Fok Ying-Tong Education Foundation of China(171064)。
文摘Understanding alkali metal ions’(e.g.,Li^(+)/Na^(+)/K^(+))transport mechanism is challenging but critical to improving the performance of alkali metal batteries.Herein using a-MnO_(2)nanowires as cathodes,the transport kinetics of Li^(+)/Na^(+)/K^(+)in the 2×2 channels of a-MnO_(2)with a growth direction of[001]is revealed.We show that ion radius plays a decisive role in determining the ion transport and electrochemistry.Regardless of the ion radii,Li^(+)/Na^(+)/K^(+)can all go through the 2×2 channels of a-MnO_(2),generating large stress and causing channel merging or opening.However,smaller ions such as Li^(+)and Na^(+)cannot only transport along the[001]direction but also migrate along the<110>direction to the nanowire surface;for large ion such as K^(+),diffusion along the<110>direction is prohibited.The different ion transport behavior has grand consequences in the electrochemistry of metal oxygen batteries(MOBs).For Li-O_(2)battery,Li^(+)transports uniformly to the nanowire surface,forming a uniform layer of oxide;Na^(+)also transports to the nanowire surface but may be clogged locally due to its larger radius,therefore sporadic pearl-like oxides form on the nanowire surface;K^(+)cannot transport to the nanowire surface due to its large radius,instead,it breaks the nanowire locally,causing local deposition of potassium oxides.The study provides atomic scale understanding of the alkali metal ion transport mechanism which may be harnessed to improve the performance of MOBs.
基金the Natural Science Foundation of China(31902166,32030104).
文摘Background Serotonin is an important signaling molecule that regulates secretory and sensory functions in the gut.Gut microbiota has been demonstrated to affect serotonin synthesis in rodent models.However,how gut microbes regulate intestinal serotonin production in piglets remains vague.To investigate the relationship between microbiota and serotonin specifically in the colon,microbial composition and serotonin concentration were analyzed in ileum-cannulated piglets subjected to antibiotic infusion from the ileum when comparing with saline infusion.Microbes that correlated positively with serotonin production were isolated from piglet colon and were further used to investi-gate the regulation mechanisms on serotonin production in IPEC-J2 and a putative enterochromaffin cell line RIN-14B cells.Results Antibiotic infusion increased quantities of Lactobacillus amylovorus(LA)that positively correlated with increased serotonin concentrations in the colon,while no effects observed for Limosilactobacillus reuteri(LR).To understand how microbes regulate serotonin,representative strains of LA,LR,and Streptococcus alactolyticus(SA,enriched in feces from prior observation)were selected for cell culture studies.Compared to the control group,LA,LR and SA supernatants significantly up-regulated tryptophan hydroxylase 1(TPH1)expression and promoted serotonin production in IPEC-J2 cells,while in RIN-14B cells only LA exerted similar action.To investigate potential mechanisms mediated by microbe-derived molecules,microbial metabolites including lactate,acetate,glutamine,andγ-aminobutyric acid were selected for cell treatment based on computational and metabolite profiling in bacte-rial supernatant.Among these metabolites,acetate upregulated the expression of free fatty acid receptor 3 and TPH1 while downregulated indoleamine 2,3-dioxygenase 1.Similar effects were also recapitulated when treating the cells with AR420626,an agonist targeting free fatty acid receptor 3.Conclusions Overall,these results suggest that Lactobacillus amylovorus showed a positive correlation with sero-tonin production in the pig gut and exhibited a remarkable ability to regulate serotonin production in cell cultures.These findings provide evidence that microbial metabolites mediate the dialogue between microbes and host,which reveals a potential approach using microbial manipulation to regulate intestinal serotonin biosynthesis.
基金Supported by the National Natural Science Foundation of China under Grant No 61404055
文摘Nano-floating gate memory devices with ZnO nano-crystals as charge storage layers are fabricated,and the influence of post-deposition annealing temperature and thickness of the ZnO layer are investigated.Atomic force microscopy and scanning electron microscopy reveal the morphology of discrete ZnO nano-crystals.For capacitance-voltage measurements,it is found that the memory device with 1.5 nm ZnO and annealed at 700℃shows a larger memory window of 4.3 V(at±6 V)and better retention characteristics than memoriy devices with2.5 nm ZnO or annealed at other temperatures.These results indicate that the nano-floating gate memory with ZnO nano-crystals can obtain good trade-off memory properties.
基金supported by the National Natural Science Foundation of China(Nos.12102423,11872354,and11627803)the Fundamental Research Funds for the Central Universities(No.WK2090000033)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB22040502)。
文摘High-speed target three-dimensional[3D]trajectory and velocity measurement methods have important uses in many fields,including explosive debris and rotating specimen trajectory tracking.The conventional approach uses a binocular system with two high-speed cameras to capture the target’s 3D motion information.Hardware cost for the conventional approach is high,and accurately triggering several high-speed cameras is difficult.Event-based cameras have recently received considerable attention due to advantages in dynamic range,temporal resolution,and power consumption.To address problems of camera synchronization difficulties,data redundancy,and motion blur in high-speed target 3D trajectory measurement,this Letter proposes a 3D trajectory measurement method based on a single-event camera and a four-mirror adaptor.The 3D trajectory and velocity of a particle flight process and a marker on a rotating disc were measured with the proposed method,and the results show that the proposed method can monitor the operational state of high-speed flying and rotating objects at a very low hardware cost.
基金supported by the National Natural Science Foundation of China(Nos.U20A20336,21935009,52002346,52022088,51971245,22205191)the Science and Technology Innovation Program of Hunan Province(No.2021RC3109)+1 种基金the Natural Science Foundation of Hunan Province,China(No.2022JJ40446)Natural Science Foundation of Hebei Province(Nos.B2020203037,B2018203297).
文摘The widespread applications of lithium-ion batteries(LIBs)generate tons of spent LIBs.Therefore,recycling LIBs is of paramount importance in protecting the environment and saving the resources.Current commercialized LIBs mostly adopt layered oxides such as LiCoO_(2)(LCO)or LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)(NMC)as the cathode materials.Converting the intercalation-type spent oxides into conversion-type cathodes(such as metal fluorides(MFs))offers a valid recycling strategy and provides substantially improved energy densities for LIBs.Herein,two typical Co-based cathodes,LCO and LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2)(NMC622),in spent LIBs were successfully converted to CoF_(2) and(Ni_(x)Co_(y)Mn_(z))F_(2) cathodes by a reduction and fluorination technique.The as converted CoF_(2) and(Ni_(x)Co_(y)Mn_(z))F_(2) delivered cell energy densities of 650 and 700 Wh/kg,respectively.Advanced atomic-level electron microscopy revealed that the used LCO and NMC622 were converted to highly phase pure Co metal and Ni_(0.6)Co_(0.2)Mn_(0.2) alloys in the used graphite-assisted reduction roasting,simultaneously producing the important product of Li_(2)CO_(3) using only environment friendly solvent.Our study provided a versatile strategy to convert the intercalation-type Co-based cathode in the spent LIBs into conversion-type MFs cathodes,which offers a new avenue to recycle the spent LIBs and substantially increase the energy densities of next generation LIBs.
基金supported by the National Natural Science Foundation of China(3187130113)the National Key R&D Program of China(2018YFD0500404)
文摘Gut microbiota is generally recognized to play a crucial role in maintaining host health and metabolism.The correlation among gut microbiota,glycolipid metabolism,and metabolic diseases has been well reviewed in humans.However,the interplay between gut microbiota and host metabolism in swine remains incompletely understood.Given the limitation in conducting human experiments and the high similarity between swine and humans in terms of anatomy,physiology,polyphagy,habits,and metabolism and in terms of the composition of gut microbiota,there is a pressing need to summarize the knowledge gained regarding swine gut microbiota,its interplay with host metabolism,and the underlying mechanisms.This review aimed to outline the bidirectional regulation between gut microbiota and nutrient metabolism in swine and to emphasize the action mechanisms underlying the complex microbiomeehost crosstalk via the gut microbiotaegutebrain axis.Moreover,it highlights the new advances in knowledge of the diurnal rhythmicity of gut microbiota.A better understanding of these aspects can not only shed light on healthy and efficient pork production but also promote our knowledge on the associations between gut microbiota and the microbiomeehost crosstalk mechanism.More importantly,knowledge on microbiota,host health and metabolism facilitates the development of a precise intervention therapy targeting the gut microbiota.
基金supported by the National Natural Science Foundation of China(Grant Nos.51201158 and51871069)Natural Science Foundation of Liaoning Province of China(20180550299 and 20180551117)+4 种基金the Natural Science Foundation of Heilongjiang Province of China(E2017030)the Science Research Project of Liaoning Province Education Department(Grant Nos.L2016004 and LQ2017014)the Liaoning Province Doctor Startup Fund(Grant No.20170520390)the Fundamental Research Funds for the Central Universities(Grant No.HEUCFM181002)the Shenyang Science and Technology Plan Projects(Grant No.F16-228-6-00)
文摘The tensile creep behavior of extruded Mg-6 Gd alloy,having the tensile yield strength of~ 110 MPa at 175 ℃,has been investigated under 175 ℃ and 150 MPa. In this study, the extruded Mg-6 Gd sample exhibits the total tensile strain of ~10.5% after the creep time of 1100 h,and the fast plastic strain of ~4.6% at the beginning of the creep test. The microstructure result suggests that the dislocation deformation is the main deformation mode during creep, and the grains with orientation close to(0001) II ED disappear after creep. The creep process containing a low creep strain has no effective promotion for the precipitation compared with the aging process without strain. The origination of creep crack is related to the formation of precipitate-free zone during creep. The work offers an important implication to research the microstructure evolution under an applied stress in a weak aging response Mg alloy.
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation of China(Nos.11872355,11627803,12072339,and 11872354)the Strategic Priority Research Program of the Chinese Academy of Science(No.XDB22040502).
文摘The mechanical force between cells and the extracellular microenvironment is crucial to many physiological processes such as cancer metastasis and stem cell differentiation. Mitosis plays an essential role in all these processes and thus an in-depth understanding of forces during mitosis gains insight into disease diagnosis and disease treatment. Here, we develop a traction force microscope method based on monolayer fluorescent beads for measuring the weak traction force (tens of Pa) of mitotic cells in three dimensions. We quantify traction forces of human ovarian granulosa (KGN) cells exerted on the extracellular matrix throughout the entire cell cycle in three dimensions. Our measurements reveal how forces vary during the cell cycle, especially during cell division. Furthermore, we study the effect of paclitaxel (PTX) and nocodazole (NDZ) on mitotic KGN cells through the measurement of traction forces. Our results show that mitotic cells with high concentrations of PTX exert a larger force than those with high concentrations of NDZ, which proved to be caused by changes in the structure and number of microtubules. These findings reveal the key functions of microtubule in generating traction forces during cell mitosis and explain how dividing cells regulate themselves in response to anti-mitosis drugs. This work provides a powerful tool for investigating cell-matrix interactions during mitosis and may offer a potential way to new therapies for cancer.
文摘Dear Editor,Intensity-modulated radiotherapy(IMRT)has a distinct advantage of high conformity and is an appropriate tech-nique for treating nasopharyngeal carcinoma(NPC).Pre-vious studies have demonstrated that anatomical changes in the external contour,shape,and location of the target and critical structures are significant and result in dosi-metric changes[1,2].Patients’quality of life and clini-cal outcomes might be improved by IMRT replanning[3].Therefore,replanning strategies should be consid-ered instead of single-planning strategies throughout the entire course of radiotherapy.However,there are sub-stantial controversies on(1)the appropriate time for tar-get redelineation,(2)how to modify the target volumes,and(3)how to evaluate the modified plans.The present study provides a new perspective in replanning with regard to these three aspects.
基金Supported by the National Natural Science Foundation of China(42090032 and 42275168).
文摘The operational numerical weather prediction system established by the China Meteorological Administration(CMA),based on the Global/Regional Assimilation and Prediction System(GRAPES)model,adopts the classical semi-implicit semi-Lagrangian(SISL)time integration algorithm.This paper describes a major upgrade to the dynamical core of the CMA global forecast system(CMA-GFS),which was successfully incorporated into operation in 2020.In the upgrade,the classical SISL is further developed into a predictor–corrector scheme,a three-dimensional(3D)reference profile instead of the original isothermal reference profile is applied when implementing the semi-implicit algorithm,and a hybrid terrain-following vertical coordinate system is also applied.The new version of the dynamical core greatly improves the model performance,the time integration reaches second-order accuracy,the time step can be extended by 50%,and the efficiency is greatly improved(by approximately 30%).Atmospheric circulation simulation is systematically improved,and deviations in temperature,wind,and humidity are reduced.The new version of the dynamical core provides a solid foundation for further development of the entire operational system of the CMA.
基金the National Natural Science Foundation of China(31972528 and 31501962)the Jiangsu Agricultural Science and Technology Innovation Fund(CX(19)3012).
文摘Short-chain fatty acids(SCFA)can regulate appetite by stimulating the secretion of satiety hormones.However,the impact of short-chain fatty acid propionate on the release of gut satiety hormones and appetite regulation in pigs is not completely understood.In this study,16 pigs were infused with saline or sodium propionate through a fistula in the caecum during a 28-day experimental period.We characterized the effects of propionate administration on peptide YY(PYY)and glucagon-like peptide 1(GLP-1)secretion from colonic tissue,and investigated the role of propionate infusion on the expression of appetite-related genes in the colon and hypothalamus.Further,the direct impact of propionate administration on the expression of orexigenic neuropeptide agouti-related protein(AgRP)in hypothalamic N38 cells was also examined.The results showed that intra-cecal infusion of propionate reduced the short-term feed intake(P<0.05)but not the long-term feed intake in pigs(P>0.05).Propionate administration stimulated PYY and GLP-1 release from colon tissue in vivo and ex vivo(P<0.05).It also upregulated PYY expression in the colonic mucosa(P<0.05).Meanwhile,the GLP-1 and PYY levels in the blood were increased after intra-cecal infusion of propionate at d 28(P<0.05).Additionally,intra-cecal infusion of propionate upregulated the mRNA and protein expression of free fatty acid receptor 2/3(FFAR2/FFAR3)in the colonic mucosa(P<0.05).Propionate infusion also downregulated the orexigenic AgRP mRNA expression(P<0.05)and upregulated the anorexigenic cocaine-and amphetamine-regulated transcript(CART)mRNA expression(P=0.09)in the hypothalamus.Moreover,propionate administration directly downregulated AgRP expression in hypothalamic N38 cells in a dose-dependent manner(P<0.05).Collectively,these findings demonstrated that cecal propionate stimulated colonic secretion of satiety hormones and suppressed appetite to reduce the short-term feed intake in pigs.This study highlights that microbial-derived propionate exerts an important role in regulating the physical functions of the host.
文摘Objective:The current meta-analysis determined the relevance of HLA-DRB1 gene polymor-phisms in a Chinese population with pulmonary tuberculosis.Methods:The CBM,CNKI,and MEDLINE databases were retrieved by computers.Domes-tic and international documents involving studies on the relevance of HLA-DRB1 gene polymor-phisms in a Chinese population with pulmonary tuberculosis were collected from the database until May 2013,and statistical analysis was performed on all of the eligible results with RevMan5.0 software.Results:Eleven case-control studies were collected,including 1364 cases in the pulmonary tuberculosis group and 1496 cases in the control group.The consolidated OR values and 95%confidence intervals of the case and control groups of HLA-DRB1*04,HLA-DRB1*15,and HLA-DRB1*16 were 1.32(1.09-1.60),1.40(1.01-1.93),and 1.36(1.01-1.83),respectively.Conclusion:HLA-DRB1*04,HLA-DRB1*15,and HLA-DRB1*16 may be susceptibility genes for pulmonary tuberculosis in a Chinese population.