Improved insensitive to input parameters trajectory clustering algorithm

The existing trajectory clustering （TRACLUS） is sensitive to the input parameters c and MinLns. The parameter value is changed a little, but cluster results are entirely different. Aiming at this vulnerability, a shielding parameters sensitivity trajectory cluster （SPSTC） algorithm is proposed which is insensitive to the input parameters. Firstly, some definitions about the core distance and reachable distance of line segment are presented, and then the algorithm generates cluster sorting according to the core dis- tance and reachable distance. Secondly, the reachable plots of line segment sets are constructed according to the cluster sorting and reachable distance. Thirdly, a parameterized sequence is extracted according to the reachable plot, and then the final trajectory cluster based on the parameterized sequence is acquired. The parameterized sequence represents the inner cluster structure of trajectory data. Experiments on real data sets and test data sets show that the SPSTC algorithm effectively reduces the sensitivity to the input parameters, meanwhile it can obtain the better quality of the trajectory cluster.

Dietary Litsea cubeba essential oil supplementation improves growth performance and intestinal health of weaned piglets

This paper was to determine the effects of dietary Litsea cubeba essential oil(LEO)supplementation on growth performance,immune function,antioxidant level,intestinal morphology and microbial composition in weaned piglets.One hundred and ninety-two piglets(Duroc×[Large White×Landrace])with 6.85±0.22 kg mean body weight weaned at 21 d of age were randomly assigned to 4 treatment groups with 8 replicates and were fed with a basal diet(CON)or CON diet containing 100(LLEO),200(MLEO)and 400(HLEO)mg/kg LEO.The results revealed that HLEO supplementation(P<0.05)increased the average daily gain on d 28 compared with CON.MLEO and HLEO supplementation decreased(P<0.05)feed conversion ratio.LEO-containing diets had a lower(P<0.05)diarrhea rate.Supple-mentation with HLEO increased(P<0.05)total antioxidant capacity(T-AOC)both in the serum and liver.Meanwhile,the supplementation of MLEO and HLEO resulted in higher(P<0.05)glutathione peroxidase(GPx)activities both in serum and liver.Supplementation of HLEO increased(P<0.05)serum immu-noglobulin A,immunoglobulin G and interleukin-10,whereas supplementation with MLEO and HLEO decreased(P<0.05)tumor necrosis factor-α.Villus height in the duodenum or jejunum was increased(P<0.05)in the HLEO group,and the villus height to crypt depth ratio in the jejunum was also improved(P<0.05)in the MLEO group.The addition of LEO increased(P<0.05)the richness and diversity of the microbial community in the cecum,which mainly increased the relative abundance of Oscillospir-aceae_UCG-005,Faecalibacterium,Blautia and Coprococcus.Piglets supplemented with HLEO increased(P<0.05)the concentration of short chain fatty acids(SCFA),including acetic acid in the cecum and propionic acid in the colon.In conclusion,these findings indicated that LEO supplementation improved growth performance and intestinal health in weaned piglets.

Physiological function and application of dietary fiber in pig nutrition:A review

Dietary fiber(DF),divided into soluble dietary fiber(SDF)and insoluble dietary fiber(IDF),has attracted increasing attention in the field of pig nutrition.Although DF reduces nutrient digestibility and inhibits energy deposition in most cases,fiber-rich feeds have been widely used in pig diets.This is not only because of lower feed costs,but also from the continuous discovery about the nutritional value of DF,mainly including the improvement of piglet intestinal health and sow reproductive performance.The addition timing has also been further considered,which potentially enables the nutritional value of DF to be accurately used in applicable pig models.Furthermore,fiber degrading enzymes have been shown to alleviate the anti-nutritional effects of DF and have ensured the improvement effect of fiber on intestinal health in young piglet models.However,the regulatory effect of fiber on pork quality is still unclear,which requires consideration of the wide range of fiber sources and the complexity of the basic diet composition,as well as the impact of pig breeds.Taken together,future research needs to gain more insight into the combined effects of SDF and IDF,processing methods,and addition timing to improve the nutritional value of DF,and further explore the physiological functions and regulatory mechanisms of DF fermentation products short-chain fatty acids in pigs.

4-Phenylbutyric acid accelerates rehabilitation of barrier function in IPEC-J2 cell monolayer model

As the first line of defence against pathogens and endotoxins crossing the intestine-blood barrier,the intestinal epithelial barrier plays a determinant role in pigs’health and growth.4-Phenylbutyric acid(4-PBA),an aromatic fatty acid,was reported to benefit homeostasis of endoplasmic reticulum and protein synthesis.However,whether 4-PBA affects intestinal epithelial barrier function in pigs is unknown.This study aimed to explore the effects of 4-PBA on the intestinal barrier function,using in vitro models of well-differentiated intestinal porcine epithelial cell(IPEC-J2)monolayers in the transwell plates.Cell monolayers with or without 4-PBA(1.0 mmol/L)treatment were challenged with physical scratch,deoxynivalenol(DON,2.0μg/mL,48 h),and lipopolysaccharide(LPS,5.0μg/mL,48 h),respectively.Transepithelial electrical resistance(TEER)and fluorescein isothiocyanate-dextran(FD-4)permeability were measured to indicate barrier integrity and permeability.Real-time PCR and Western blot were conducted to determine relative gene and protein expressions of tight junction proteins.As expected,physical scratch,DON,and LPS challenges decreased TEER and increased FD-4 permeability.4-PBA treatment accelerated cell mitigation and rehabilitation of the physical scratch-damaged intestinal epithelial barrier but did not alleviate DON or LPS induced barrier damage.However,once 48-h DON and LPS challenges were removed,rehabilitation of the epithelial barrier function of IPEC-J2 monolayer was accelerated by the 4-PBA treatment.Also,the relative gene and protein expressions of zonula occludens-1(ZO-1),occludin,and claudin-1 were further upregulated by the 4-PBA treatment during the barrier rehabilitation.Taken together,4-PBA accelerated the IPEC-J2 cell monolayer barrier recovering from physical scratch,DON-,and LPS-induced damage,via enhancing cell mitigation and expressions of tight junction proteins.

电渣重熔结晶器旋转对M2高速钢凝固过程的影响

研究了自行设计的结晶器可旋转的电渣炉的旋转速率对M2高速钢凝固过程的影响,采用双极串联-电渣重熔方法,对不同结晶器转速下所制M2高速钢的二次枝晶、冷却速率、渗透率和渣皮厚度进行统计、计算和分析。结果表明,随结晶器转速增大,M2高速钢中心和边部的枝晶被打碎,结晶器转速越快,枝晶破碎越明显。结晶器转速由0增至19 r/min,M2高速钢在中心和边部的平均二次枝晶间距分别减小19.47%和25.23%,平均冷却速率分别增大97.01%和148.06%,平均渗透率分别降低34.94%和44.04%。结晶器旋转能将渣皮厚度降低40.41%,渣壳厚度的方差由0.163降至0.003,渣皮变得均匀,增大了金属熔池向外传热,使金属熔池变浅;另一方面,M2高速钢枝晶破碎、平均二次枝晶间距减小和渗透率降低使M2高速钢在凝固过程中的偏析得到控制,因而结晶器旋转可提高M2高速钢的凝固质量。

电渣重熔过程结晶器旋转对钢中夹杂物的影响

基于自行设计的双极串联结晶器旋转电渣重熔炉,采用ASPEX全自动夹杂物分析仪研究了结晶器转速对M2电渣锭洁净度的影响。结果表明,不论结晶器是否旋转,电渣锭中的夹杂物组成基本不变,主要由Al2O3, Al2O3–MnS, Al2O3–SiO2–CaO–MnS,MgO–Al2O3–SiO2–Ca O–MnO,MgO–Al2O3–SiO2–CaO–TiO2–MnS,Al2O3–SiO2–CaO–MnO–TiO2组成,其中以Al2O3,Al2O3–Si O2–CaO–MnO–TiO2和Al2O3–MnS数量最多。结晶器静止电渣重熔时,钢中的夹杂物数量较多,且存在50mm以上的大颗粒夹杂物,而结晶器转速为6和13 r/min时,夹杂物数量减少,大颗粒夹杂含量大大降低;转速增至19 r/min时,夹杂物数量及尺寸又进一步增加,同时钢中全氧含量、氮含量明显增加。电渣锭中大颗粒夹杂物得以去除的主要原因是结晶器旋转导致金属自耗电极末端的熔融层变薄、熔滴尺寸变小,渣–金接触面积增大,促进了夹杂物被熔渣去除;过快的转速会增加自耗电极氧化、减少渣–金接触时间,从而降低电渣重熔过程的精炼能力。