Cryptosporidium spp., ubiquitous enteric parasitic protozoa of vertebrates, recently emerged as an important cause of economic loss and zoonosis. The present study aimed to determine the distribution and species of Cryptosporidium in post-weaned and adult pigs in Shaanxi province, northwestern China. A total of 1,337 fresh fecal samples of post-weaned and adult pigs were collected by sterile disposable gloves from 8 areas of Shaanxi province. The samples were examined by Sheather's sugar flotation technique and microscopy at × 400 magnification for Cryptosporidium infection, and the species in positive samples was further identified by PCR amplification of the small subunit (SSU) rRNA gene. A total of 44 fecal samples were successfully amplified by the nested PCR of the partial SSU rRNA, with overall prevalence of 3.3%. The average prevalence of Cryptosporidium infection in each pig farms ranged from 0 to 14.4%. Species identification by sequencing of SSU rRNA gene revealed that 42 (3.1%) samples were Cryptosporidium suis and 2 (0.15%) were Cryptosporidium scrofarum. C. suis had the highest prevalence (7.5%) in growers and the lowest in breeding pigs (0.97%). C. suis was the predominant species in pre-weaned and adult pigs, while C. scrofarum infected pigs older than 3 months only. A season-related difference of C. suis was observed in this study, with the highest prevalence in autumn (5.5%) and the lowest (1.7%) in winter. The present study provided basic information for control of Cryptosporidium infection in pigs and assessment of zoonotic transmission of pigs in Shaanxi province, China.

Lancet flukes parasitize the bile ducts and gall bladder of a range of mammals, including humans, causing dicrocoeliosis. In the present study, we sequenced and characterized the complete mitochondrial (mt) genomes as well as the first and second internal transcribed spacers (ITS-1 and ITS-2=ITS) of nuclear ribosomal DNA (rDNA) of two lancet flukes, Dicrocoelium chinensis and D. dendriticum. Sequence comparison of a conserved mt gene and nuclear rDNA sequences among multiple individual lancet flukes revealed substantial nucleotide differences between the species but limited sequence variation within each of them. Phylogenetic analysis of the concatenated amino acid and multiple mt rrnS sequences using Bayesian inference supported the separation of D. chinensis and D. dendriticum into two distinct species-specific clades. Results of the present study support the proposal that D. dendriticum and D. chinensis represent two distinct lancet flukes. While providing the first mt genomes from members of the superfamily Plagiorchioidea, the novel mt markers described herein will be useful for further studies of the diagnosis, epidemiology and systematics of the lancet flukes and other trematodes of human and animal health significance.

Robust visual tracking has become an important topic in the field of computer vision. The integration of cues such as color, shape features has proved to be a promising approach to robust visual tracking. In this paper, an algorithm is presented which integrates Hu moments and color histogram. Moreover, this paper integrates the ABCshift algorithm to overcome color features drawbacks which easily lead to loss of target object when the color of object is similar to the color of background. The proposed algorithm has been compared with other trackers using challenging video sequences. Experimental work demonstrates that the proposed algorithm has strong robust and improves the tracking performance.

In order to develop a new broad-spectrum multi-epitope vaccine of type A foot-and-mouth disease virus(FMDV),one DNA fragment encoding VP1main epitope 135aa-160aa and 200aa-213aa was designed and synthesized according with the VP1gene sequences of six representative FMDV type A strains from GenBank database,and then attached to the gene of heavy chain constant region of bovine IgG.Via using the XhoⅠ,EcoRⅠand BamHⅠsites,both were cloned into the pET-30a(+)vector to form the recombinant plasmid pRE2IgG,with the gene of heavy chain constant region of bovine IgG.By using the BamHⅠ,EcoRⅠand XhoⅠsites,both of the two genes were cloned into the pET-30a(+)vector to form the recombinant plasmid pRE2IgG,and then transformed the recombinant plasmid into E.coli BL21(DE3)competent cells.SDS-PAGE and Western Blot results indicated that the fusion protein pET30a105106 IgG was highly expressed in the form of inclusion bodies in E.coli induced by IPTG,and its molecular weight is about 60ku,and can react with FMDV type A positive serum.

The present investigation was undertaken to determine the prevalence of common intestinal parasites in domestic pigs in Shaanxi province of China between May 2011 and February 2012. A total of 1339 pig fecal samples were collected from pre-weaners (252),growers (360), fatteners (417), breeding sows and boars (310) in 9 farms located in 8 counties/districts. Among them, 387 fecal samples were positive for intestinal parasites. Growers had the highest infection rate (41.4%), while pre-weaners had the lowest(22.2%). But only 39 pigs were infected with multiple parasites. The common intestinal parasites were Ascaris suum (10.23%), Strongyloides spp. (6.49%), Eimeria spp.(6.35%) and Cryptosporidium spp. (4.63%). Of the risk factors for intestinal parasite infection investigated in the present study, the farm management system played a remarkable role in the occurrence and intensity of intestine parasite infection. These results suggested that the efficient prevention and control measures should be taken to control intestinal parasites infection in pig in Shaanxi province. Key words: Intestinal parasites, prevalence, swine, Shaanxi province.

Dicrocoelium chinensis is commonly known as the "lancet fluke" or "small liver fluke" which lives in the bile ducts and gall bladder of domestic and wild ruminants. In this study, we examined sequence variability in two mitochondrial (mt) genes, namely cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes, among D. chinensis isolated from domestic yaks in Gansu and Sichuan provinces, China. A portion of the cox1 (pcox1) and nad1 (pnad1) genes was amplified by PCR separately from the individual adult D. chinensis, and the amplicons were subjected to sequencing from both directions. The lengths of the sequences of pcox1 and pnad1 were 358 and 458 bp, respectively. The A+T contents of the sequences were 58.94-59.22% for pcox1 and 60.04-60.48% for pnad1, respectively. The intra-specific sequence variations within D. chinensis were 0-0.84% for pcox1 and 0-0.87% for pnad1. The inter-specific sequence differences among members of the examined trematodes were significantly higher, being 22.9-29.3% and 33.6-41.5% for pcox1 and pnad1, respectively. Phylogenetic analysis utilizing combined sequences of pcox1 and pnad1 using Bayesian inference revealed that all of the D. chinensis isolates grouped together with high statistical support. These findings demonstrated the existence of low intra-specific variation in mitochondrial DNA (mtDNA) sequences among the D. chinensis isolates from domestic yaks in China and had implications for studying the molecular epidemiology and population genetics of D. chinensis.

We determined the complete mitochondrial DNA (mtDNA) sequence of a fluke, Paramphistomum cervi (Digenea: Paramphistomidae). This genome (14,014 bp) is slightly larger than that of Clonorchis sinensis (13,875 bp), but smaller than those of other digenean species. The mt genome of P. cervi contains 12 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and 2 non-coding regions (NCRs), a complement consistent with those of other digeneans. The arrangement of protein-coding and ribosomal RNA genes in the P. cervi mitochondrial genome is identical to that of other digeneans except for a group of Schistosoma species that exhibit a derived arrangement. The positions of some transfer RNA genes differ. Bayesian phylogenetic analyses, based on concatenated nucleotide sequences and amino-acid sequences of the 12 protein-coding genes, placed P. cervi within the Order Plagiorchiida, but relationships depicted within that order were not quite as expected from previous studies. The complete mtDNA sequence of P. cervi provides important genetic markers for diagnostics, ecological and evolutionary studies of digeneans.

14day-old chickens were inoculated with Eimeria maxima Yangling strain(YLm),the assay of drug resistance of YLm to 3coccidiostats(ammonia-topiramate,diclazuril premix and sufanhmide chlorine paradiazine sodinm) were conducted.Drug resistances were assessed by percent of optimum anticoccidial activity(POAA),anticoccidial index(ACI),relative oocysts production(ROP) and reduction of lesion scores(RLS).The experiment results revealed that YLm was complete resistant to diclazuril premix,ligh resistant to sufanhmide chlorine paradiazine sodinm,sensitive to ammonia-topiramate.

A survey of intestinal parasite infection in cattle was conducted in Shaanxi province, northwestern China from November 2010 to January 2012, including Qinchuan cattle and dairy cattle. A total of 1736 fecal specimens (783 and 953 for Qinchuan and dairy cattle, respectively) in 18 farms (including 7 Qinchuan cattle and 11 dairy cattle farms) were obtained. The prevalences of intestinal parasites in Qinchuan cattle were slightly different from that in dairy cattle but with no statistically difference (P>0.05) except nematodes. Coccidian oocysts were the most common intestinal parasite, which were found in all cattle farms with prevalences ranged from 17.44 to 67.69%. The nematode eggs were found in 17 of 18 farms investigated with prevalences ranged from 0 to 43.75%. Cryptosporidium oocysts and the cestode eggs were only found in 10 and 5 farms, respectively. The present study showed that the prevalences of the intestinal parasites were affected by the related factors of geographical region, breed, age, and season. Therefore, the integrated strategies and measures should be taken to control intestinal parasites infection in cattle in Shaanxi province.

The nuclear ribosomal DNA (rDNA) region spanning 5.8S rDNA and the second internal transcribed spacer (ITS-2) of Baylisascaris schroederi isolated from the Qinling subspecies of giant panda in Shaanxi Province, China were amplified and sequenced. Sequence variations in the two rDNA regions within B. schroederi and among species in the family Ascarididae were examined. The lengths of B. schroederi 5.8S and ITS-2 rDNA sequences were 156 bp and 327 bp, respectively, and no nucleotide variation was found in these two rDNA regions among the 20 B. schroederi samples examined, and these ITS-2 sequences were identical to that of B. schroederi isolated from giant panda in Sichuan province, China. The inter-species differences in 5.8S and ITS-2 rDNA sequences among members of the family Ascarididae were 0-1.3% and 0-17.7%, respectively. Phylogenetic relationships among species in the Ascarididae were re-constructed by Bayesian inference (Bayes), maximum parsimony (MP), and maximum likelihood (ML) analyses, based on combined sequences of 5.8S and ITS-2 rDNA. All B. schroederi samples clustered together and sistered to B. transfuga with high posterior probabilities/bootstrap values, which further confirmed that nematodes isolated from the Qinling subspecies of giant panda in Shaanxi Province, China represent B. schroederi. Because of the large number of ambiguously aligned sequence positions (difficulty of inferring homology by positions), ITS-2 sequence alone is likely unsuitable for phylogenetic analyses at the family level, but the combined 5.8S and ITS-2 rDNA sequences provide alternative genetic markers for the identification of B. schroederi and for phylogenetic analysis of parasites in the family Ascarididae.

In the present study, the phylogenetic position of Oesophagostomum asperum was examined based on the sequences of internal transcribed spacer (ITS) of ribosomal DNA. The DNA fragment spanning 3' end of 18S rDNA, complete ITS-1, 5.8S, ITS-2 rDNA, and 5' end of 28S rDNA was amplified from six nematodes morphologically identified as Oesophagostomum asperum from 3 infected Cashmere goats (one pair parasites for each animal) in Shaanxi province, China. The amplicons were sequenced, and compared with corresponding sequences of other Oesophagostomum species available in GenBank (TM). The ITS-1, 5.8S, and ITS-2 sequences of all the parasites were 374, 153 and 259 bp in length, respectively, with no sequence difference in 5.8S rDNA and only very subtle sequence heterogeneity in ITS-1 and ITS-2 rDNA. The interspecies difference in ITS-1 and ITS-2 rDNA between O. asperum and other Oesophagostomum species showed that O. asperum is closely related to O. venulosum. Phylogenetic studies using Bayesian analysis revealed that all the O. asperum isolates clustered together sistered to O. venulosum. Our study characterized the O. asperum at molecular level for the first time, which would have important implications for further molecular identification and differentiation, and the genetic analysis of this nematode between specimens and hosts and the haplotypic variation and within regions in Shaanxi province and other locations.

Two continuous field variables, called as continuity tensor and damage variable tensor, are used to describe the anisotropic responses of an elastic-brittle material under transverse impact load. Based on the continuum damage mechanics, anisotropic damage constitutive equations in both full and incremental forms are proposed here. The expressions of effective elastic module tensor, damage variable tensor and damage propagation force tensor are further derived, and the methods for determining the tensors are explained in detail. An example of strain and damage response of a fiber reinforced composite laminated plate under transverse impact load is employed to demonstrate the application of this theory. In the example, the damage variable coupled with geometric large deformation of laminated plate is also considered. The calculating results illustrate the influence of damage on strain field in the impacted laminated plate.

A dynamic contact algorithm for the case of an isotropic projectile impacting an orthotropic target is proposed in this paper. The projectile and the target are scattered into finite elements, then the process of the projectile impacting the target is regarded as a dynamic contact process between a node of the projectile and a surface of an element of the target. The dynamic contact conditions are determined based on the conditions of their deformation and the law of conservation of momentum. The effect of propagating speed of elastic wave in different materials on transmission of momentum is also accounted in calculating the conservation of momentum. In order to validate the algorithm, two examples are given and compared to references.

简述了竹材增强不饱和聚酯小型船体的结构和铺层设计的原则和结果;给出了用RTM工艺成型这种船体的工艺流程、工艺条件和模具设计思路;总结了竹材含水量对竹材自身强度及其与基体材料间粘结强度的影响;探讨了几种常用廉价树脂作为竹材增强船体基体材料的可能性,制得了竹片仿形编织物增强不饱和聚酯船体.

The sol-gel method is chosen to prepare Al2O3 matrix in order to fabricate •-Alumina matrix composite reinforced by three dimensional carbon fiber braided preform. Some Al2O3 sols are prepared by hydrolysis aluminum salt or aluminum alkoxide, then, the sols prepared can infiltrate into the preform. Thus gelation and pyrolysis in the preform can be carried out. After pyrolysis, Al2O3 matrix composite reinforced by carbon fiber woven preforms could be obtained.

The diameter and the specific surface area of silica particles have great effect on the properties of silica gel, so they should be regarded as the important performance index of silica gel. The methods to determine the diameter and the specific surface area of silica particles were discussed.

A model was developed to express the microdamage, macrodamages (including debond matrix crack and fiber break) and the fracture process of composite impacted by a projectile. It was assumed that the nonlinearity of composites was induced by the microdamage produced in impact process and was considered in constitutive equations. A maximum strain criterion was also presented. It can be used to analyze the macrodamages of composites. The process of the macrodamage was simulated by the nodal separate technique.

The processing of ceramic matrix composites (CMC) reinforced with 3D-braid woven fabrics via polycarbosilane (PCS) pyrolysis was investigated. Also studied were the influences of different kinds of processing on the macro and micro properties of composites. Several ways were proposed, which can improve the processing and enhance the properties of composites. The results indicate that the pyrolysis time is considerably reduced by infiltration-curing-pyrolysis of a PCS/DVB system, and the densification efficiency is significantly enhanced compared with PCS/Xylene solution infiltration. The 3D-braid C f/SiC CMC specimens have a density of 1.65g/cm 3, a flexural strength of 326MPa and a fracture toughness of 13.72MPa��m 1/2 after infiltration-curing-pyrolysis cycles of 7 times for the PCS/DVB system, and have a density of 1.54g/cm 3, a flexural strength of 243MPa and a fracture toughness of 8.19MPa��m 1/2 after infiltration-pyrolysis for the PCS/Xylene system. The fracture surfaces of the flexural specimens were also investigated by SEM including fibers pull-out, fibers fracture, etc.

Based on continuum damage mechanics, the deformation and damage process of composite laminates impacted by projectile have been studied theoretically. The basic equations were also derived. The composites are of anisotropy and nonhomogeneity, the microdamage induced by impact is anisotropic and results in nonlinearity of materials. The local large deformations of the target construct geometrical nonlinearity. The microdamages which include cracking of matrix, fibers fracture within lamina and interface debonded as well are treated by the nodal division for finite element analysis. The projectile made of steel is assumed to be linear elastic and its damage in the impact process is not take into account. The theory used can simulate the process of damage and deformation of composite laminates impacted by projectile.

The characteristics of silica-sol and the application for precision casting were introduced. Using silica-sol has the advantages over using ethyl silicate hydrolytic liquid in simple preparation, low cost and nonpollution as a ceramic mold is applied for precision casting. The problems and the future development of the silica-sol were discussed.