209 research outputs found
F4ac-fimbrial-binding proteins in porcine milk and the absorption of colostral proteins by piglets
F4 positive enterotoxigenic Escherichia coli (ETEC) is the most common pathogen causing neonatal diarrhea in piglets. The pathogenesis requires the attachment of ETEC to the intestinal brush border, mediated by F4 fimbria. Colostral anti-F4 antibodies and some non-immunoglobulin porcine skim milk proteins can bind F4 and prevent colonization and infection by F4-positive ETEC. Little is known, however, about the F4-binding ability of porcine milk fat globule membrane (MFGM) proteins. In addition, the knowledge of the absorption of porcine colostral proteins into the blood of neonatal piglets is limited, despite the well accepted concept that in neonatal piglets, protein absorption from the intestine is non-selective.
In this study, the ability of porcine MFGM proteins to bind purified F4ac (one of the three subtypes of F4 fimbriae) was investigated. Porcine MFGM proteins were first separated by 2D SDS-PAGE and subsequently identified by mass spectrometry. Overlay western Blot was then employed to demonstrate the interaction between porcine MFGM proteins and purified F4ac. Several proteins from porcine MFGM reacted with F4ac, and of these, lactadherin, butyrophilin, adipophilin, and acyl-CoA synthetase 3 reacted strongly. The biological function of these proteins in vivo was not investigated but it is possible that their interaction with F4ac positive ETEC interferes with bacterial attachment and colonization.
In order to investigate protein absorption by neonatal piglets after natural suckling, the protein profiles of the plasma of pre-suckling and 24 h post-suckling neonatal piglets were studied by 2D SDS-PAGE. Those plasma proteins that increased prominently after suckling were then identified by mass spectrometry. Only immunoglobulins were unequivocally determined to be absorbed, because they were absent before suckling and present in large quantity in plasma 24 h after suckling. The absorption of other colostral proteins was either equivocal or not detectable by our detection methods. These results suggest that, unlike immunoglobulins, major non-immunoglobulin proteins in porcine colostrum may not be absorbed into systemic circulation in substantial amounts
Is Porcine Periweaning Failure-to-Thrive Syndrome an Infectious Diseases?
Porcine Periweaning Failure-to-Thrive syndrome (PFTS) is a clinical syndrome of newly weaned pigs with unknown etiology and characterized by anorexia, lethargy and progressive debilitation. The hypothesis of this thesis is that PFTS is an infectious disease. Investigation in an index farm affected by PFTS from Saskatchewan Canada ruled out most common swine pathogens as the etiology and identified several lesions that were consistent across many cases. A larger study including multiple farms in North America was then undertaken. A total of 8 farms were investigated, within which 5 met the clinical definition of PFTS. Gross and histological examinations were performed on 8 case and 4 control pigs on each farm. Detection of relevant porcine pathogens, complete blood count, serum chemistry, and serum cytokine analysis were performed on each pig. Thymic atrophy, superficial gastritis and small intestinal villous atrophy were significantly more prevalent in case pigs compared to control pigs. All case pigs had at least two of these three lesions. All case and control pigs were negative for porcine reproductive and respiratory syndrome virus, swine influenza virus and were free of porcine circovirus associated diseases. Although several pathogens, such as porcine cytomegalovirus, haemagglutinating encephalomyelitis virus, porcine enteric calicivirus, group A rotavirus, enteroviruses and Cystoisospora suis were detected in some of the case and control pigs, none were associated with clinical status. Clinical pathology findings of case pigs was consistent with anorexia and dehydration, such as increases in haematocrit, blood urea, serum bilirubin, albumin, beta-hydroxybutyrate and decreases in blood glucose, calcium and phosphorous. Case pigs had similar levels to IL1-β than control pigs, which suggested that PFTS was not a result of excessive cytokines. In subsequent experiments, a snatched-farrowed porcine-colostrum-deprived (SF-pCD) pig model was developed and tissue homogenates were used to inoculate SF-pCD pigs in an attempt to reproduce the clinical signs of PFTS. The SF-pCD pigs were immunologically characterized and shown to be suitable for inoculation studies. However, inoculation of tissue homogenate from PFTS pigs failed to reproduce the clinical signs of PFTS in SF-pCD pigs. All together, PFTS is a clinical syndrome with consistent pathological and serum analytical changes among affected pigs. Despite the efforts of this research to establish an infectious etiology, there is a lack of evidence that PFTS is an infectious disease
R&D offshoring and technology learning in emerging economies: Firm-level evidence from the ICT industry
This paper studies the impact of the R&D offshoring of multinational enterprises on the firms in host emerging economies. We develop a two-stage non-cooperative game to analyze the strategic interaction between multinational and host country enterprises engaged in R&D investment. An empirical analysis of 12,309 manufacturing firms in the ICT industry in China shows that R&D offshoring has a positive effect on the intensity of the R&D of host country firms. However, the magnitude of the impact depends on both the technological and geographical distance between the multinational and host country firms. The policy implications of these findings are that the governments of host country should be cautious about allowing advanced multinational R&D investment in under-developed sectors, but they should encourage such investment in developed sectors; and that local governments should be involved in R&D policy making because the positive impact of multinational R&D offshoring diminishes as the geographical distance between the multinational and host country firms increases.Research and Development, Offshoring, Spillovers, Emerging Economies
Daily return distribution forecast incorporating intraday high frequency information in China’s stock market
The stock market forecast is an important and challenging issue. Its
distribution forecast of returns can provide information that is more
complete, compared to point forecast and interval forecast. As intraday
high-frequency information is available, we incorporate intraday
returns into the predictive modelling of daily return distribution in
two ways: realized volatility and scale calibration. Three parametric
models, EGARCH, EGARCH-X, and realGARCH, and two nonparametric
models, NP and realNP, are used. Our improved NP model, the
realNP model, is based on intraday returns calibration. The results
show that intraday information improves goodness-of-fit and forecasting
effect, and the realGARCH model is relatively the best.
According to the realNP model results, the intraday returns can only
contribute about a 30% description of the daily distribution and less
than 1% information for a one-step-ahead distribution forecast.
Furthermore, three combinations are considered, and the log-score
and CRPS combinations are found to have direction predictability
and excess profitability statistically. The non-short-selling situation
consistently has more excess profits than the short-selling situation,
which implies that the non-short-selling rule protects investors. This
study reveals the importance of incorporating intraday information
and model combinations for stock market forecast modelling
Research on College Students' Classroom Learning Based on Informatization to Promote English Education System in China
English education in the education of future employees will be essential as a means of identifying and developing personal capabilities as well as serving as a catalyst for the complete informatization of society. Intercultural literacy is a secondary goal of English instruction in China; the main goal is for students to become fluent communicators. The advent of informatization has ushered in a period of fast change across many different business sectors and the globe overall. Instruction in the English language receives a significant focus and investment in China. Traditional methods of education are no longer enough to satisfy the requirements that globalization and Chinese culture impose in this technological age. To improve overall academic achievement, standard classroom evaluation practices need to be revised. With the proliferation of information technology, we have high hopes that this article will be able to considerably enhance the performance of English classroom instruction in school classrooms by offering a new method for assessment. To begin, we compile each student's dataset with data on their English education. Following the preprocessing of the dataset with the Hidden Markov Model (HMM) Stemming Algorithm and the application of information technology with the Radial Basis Coherent Deep Neural Network (RBCDNN), the dataset is evaluated for statistical significance with the Panel Unit Test and the Housman test. The effectiveness of this research is evaluated, and the results are compared to those of previous studies. The findings of this investigation are shown in the form of a chart thanks to the origin tool
Periweaning Failure to Thrive Syndrome (PFTS): Is There a Genetic Component?
Periweaning Failure to Thrive Syndrome (PFTS) is a serious and potentially fatal disorder with variable morbidity and mortality rates that have been reported in US and Canadian farms. A genetic basis has been hypothesized. To investigate what regions of the genome could be linked to that, a total of 70 affected and 37 non-affected piglets were genotyped with over 60,000 genetic markers to investigate genetic differences between the two groups. This allows for the identification of genomic regions that could be linked to resistance to the disease providing new insights and knowledge on the genetic basis of this syndrome
Persistent Zika virus infection in porcine conceptuses is associated with elevated in utero cortisol levels
Persistent Zika virus infection in porcine conceptuses is associated with elevated <i>in utero</i> cortisol level
The Application of Cdio Model in Spoken English Teaching Among Preschoolers in China
This study discussed how the CDIO model could be applied to the teaching of spoken English to preschoolers in China through the literature review approach. spoken English teaching plays an important role in developing good spoken expression and communicative skills among preschoolers in China, yet there are currently problems existing such as a single teaching method and a mismatch between teaching content and students’ actual needs. CDIO model, as a teaching model with engineering practice as the core, has been widely used in higher education. This study reviewed the basic principles of the CDIO model and successful cases in higher education, discussed the compatibility of the CDIO model with the goals of spoken English teaching for preschoolers and proposed methods and strategies for applying the CDIO model to teaching spoken English to preschoolers in China by reviewing the current situation and problems of it. Specifically, this study explored how to use the CDIO model to promote preschoolers spoken English teaching from three aspects: curriculum design, teaching methods, and evaluation system. It is shown that the application of the CDIO model in teaching spoken language to preschoolers has great feasibility and practicality and could effectively improve preschoolers’ spoken expression and communicative competence. However, further research and evaluation of the effectiveness of the CDIO model in early childhood spoken language teaching is needed, and more teaching strategies and methods suitable for preschoolers should be explored. This study provides theoretical and practical references for introducing the CDIO model into the teaching of spoken language for preschoolers in China and offers new ideas for the improvement and development of spoken English teaching for preschoolers
Phylogenetic analysis of porcine circovirus 3 circulating in Canadian pigs
Introduction: Porcine circovirus 3 (PCV3) has been detected in pigs worldwide and
associated with several clinical signs.
Methods: To investigate the genetic diversity of PCV3 strains circulating in Canada,
44 PCV3 positive samples from Saskatchewan (2/44), Manitoba (2/44), Quebec (4/44),
Alberta (11/44) and Ontario (25/44) submitted to diagnostic laboratories in Canada
between 2019 and 2021 were sequenced and analyzed.
Results: Phylogenetic analysis of capsid genes showed that all of the 44 Canadian
strains classified into PCV3a and segregated into seven lineages with common amino
acid changes observed at A24V, R27K, N56D, T77S, Q98R, L150I (F) and R168K
positions.
Conclusion: Future studies are required to determine whether the polymorphisms in
capsid proteins, as revealed in this study, could be associated with differences in the
pathogenicity or antigenicity of PCV3 strains. This is the first phylogenetic analysis of
PCV3 strains among different provinces in Canada
Mesenchymal stem cells alleviate bacteria‐induced liver injury in mice by inducing regulatory dendritic cells
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102718/1/hep26670.pd
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