150 research outputs found
Stability Analysis and Variational Integrator for Real-Time Formation Based on Potential Field
This paper investigates a framework of real-time formation of autonomous vehicles by using potential field and variational integrator. Real-time formation requires vehicles to have coordinated motion and efficient computation. Interactions described by potential field can meet the former requirement which results in a nonlinear system. Stability analysis of such nonlinear system is difficult. Our methodology of stability analysis is discussed in error dynamic system. Transformation of coordinates from inertial frame to body frame can help the stability analysis focus on the structure instead of particular coordinates. Then, the Jacobian of reduced system can be calculated. It can be proved that the formation is stable at the equilibrium point of error dynamic system with the effect of damping force. For consideration of calculation, variational integrator is introduced. It is equivalent to solving algebraic equations. Forced Euler-Lagrange equation in discrete expression is used to construct a forced variational integrator for vehicles in potential field and obstacle environment. By applying forced variational integrator on computation of vehicles' motion, real-time formation of vehicles in obstacle environment can be implemented. Algorithm based on forced variational integrator is designed for a leader-follower formation
The C/EBP Homologous Protein (CHOP) Transcription Factor Functions in Endoplasmic Reticulum Stress-Induced Apoptosis and Microbial Infection
Apoptosis is a form of cell death by which the body maintains the homeostasis of the internal environment. Apoptosis is an initiative cell death process that is controlled by genes and is mainly divided into endogenous pathways (mitochondrial pathway), exogenous pathways (death receptor pathway), and apoptotic pathways induced by endoplasmic reticulum (ER) stress. The homeostasis imbalance in ER results in ER stress. Under specific conditions, ER stress can be beneficial to the body; however, if ER protein homeostasis is not restored, the prolonged activation of the unfolded protein response may initiate apoptotic cell death via the up-regulation of the C/EBP homologous protein (CHOP). CHOP plays an important role in ER stress-induced apoptosis and this review focuses on its multifunctional roles in that process, as well as its role in apoptosis during microbial infection. We summarize the upstream and downstream pathways of CHOP in ER stress induced apoptosis. We also focus on the newest discoveries in the functions of CHOP-induced apoptosis during microbial infection, including DNA and RNA viruses and some species of bacteria. Understanding how CHOP functions during microbial infection will assist with the development of antimicrobial therapies
Newcastle disease virus induces testicular damage and disrupts steroidogenesis in specific pathogen free roosters
Newcastle disease (ND), which is caused by Newcastle disease virus (NDV), can cause heavy economic losses to the poultry industry worldwide. It is characterised by extensive pathologies of the digestive, respiratory, and nervous systems and can cause severe damage to the reproductive system of egg-laying hens. However, it is unknown whether NDV replicates in the male reproductive system of chickens and induces any pathologies. In this study, we selected a representative strain (i.e. ZJ1) of the most common genotype (i.e. VII) of NDV to investigate whether NDV can induce histological, hormonal, and inflammatory responses in the testes of specific pathogen free (SPF) roosters. NDV infection increased the expression of toll like receptor TLR3, TLR7, MDA5, IFN-α, IFN-β, IFN-γ, IL-8, and CXCLi1 in the testes of NDV-infected roosters at 5 days post-infection (dpi). Severe histological changes, including decrease in the number of Sertoli cells and individualized, shrunken spermatogonia with pyknotic nuclei, were observed at 3 dpi. At 5 dpi, the spermatogenic columns were disorganized, and there were fewer cells, which were replaced by necrotic cells, lipid vacuoles, and proteinaceous homogenous material. A significant decrease in the plasma concentrations of testosterone and luteinizing hormone (LH) and the mRNA expression of their receptors in the testes, steroidogenic acute regulatory protein, cytochrome P450 side-chain cleavage enzyme, and 3β-hydroxysteroid dehydrogenase in the NDV-infected group was observed relative to those in the control group (P < 0.05). Collectively, these results indicate that NDV infection induces a severe inflammatory response and histological changes, which decrease the steroidogenesis. © 2020 The Author(s)
Experimental infection of duck origin virulent Newcastle disease virus strain in ducks
Potential of genotype VII Newcastle disease viruses to cause differential infections in chickens and ducks
Newcastle disease (ND), caused by ND virus (NDV), is one of the most infectious and economically important diseases of the poultry industry worldwide. While infections are reported in a wide range of avian species, the pathogenicity of chicken-origin virulent NDV isolates in ducks remains elusive. In this study, two NDV strains were isolated and biologically and genetically characterized from an outbreak in chickens and apparently healthy ducks. Pathogenicity assessment indices, including the mean death time (MDT), intracerebral pathogenicity index (ICPI) and cleavage motifs in the fusion (F) protein, indicated that both isolates were velogenic in nature. While these isolates carried pathogenic characteristics, interestingly they showed differential pathogenicity in ducks. The chicken-origin isolate caused high (70%) mortality, whereas the duck-origin virus resulted in low (20%) mortality in 4-week-old ducks. Intriguingly, both isolates showed comparable disease pathologies in chickens. Full-genome sequence analysis showed that the virus genome contains 15 192 nucleotides and carried features that are characteristic of velogenic strains of NDV. A phylogenetic analysis revealed that both isolates clustered in class II and genotype VII. However, there were several mutations in the functionally important regions of the fusion (F) and haemagglutinin-neuraminidase (HN) proteins, which may be responsible for the differential pathogenicity of these viruses in ducks. In summary, these results suggest that NDV strains with the same genotype show differential pathogenicity in chickens and ducks. Furthermore, chicken-origin virulent NDVs are more pathogenic for ducks than duck-origin viruses. These findings propose a role for chickens in the evolution of viral pathogenicity and the potential genetic resistance of ducks to poultry viruses
Supplementation of Vitamin E Protects Chickens from Newcastle Disease Virus-Mediated Exacerbation of Intestinal Oxidative Stress and Tissue Damage
BACKGROUND/AIMS: Newcastle disease virus (NDV) causes a highly devastating and contagious disease in poultry, which is mainly attributed to extensive tissue damages in the digestive, respiratory and nervous systems. However, nature and dynamics of NDV-induced oxidative stresses in the intestine of chickens remain elusive. METHODS: In this study, we examined the magnitude of intestinal oxidative stress and histopathological changes caused by the virulent NDV infection, and explored the protective roles of vitamin E (vit. E) in ameliorating these pathological changes. For these purposes, chickens were divided into four groups namely i) non supplemented and non-challenged (negative control, CON); ii) no supplementation of vit. E but challenged with ZJ1 (positive control, NS+CHA); iii) vit. E supplementation at the dose of 50 IU/day/Kg body weight and ZJ1 challenge (VE50+CHA); and 4) vit. E supplementation at the dose of 100 IU/day/Kg body weight and ZJ1 challenge (VE100+CHA). In all groups, we analyzed concentrations of glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO), total antioxidant capacity (T-AOC), and activity of glutathione S-transferase (GST), superoxide dismutase (SOD), catalase (CAT) using biochemical methods. The virus loads were determined by quantitative RT-PCR and antibody titers by hemagglutination inhibition assays. We also examined the histopathological changes in the duodenal and jejunal mucosa at 3 and 5-day post infection (dpi) with NDV. RESULTS: A significant elevation in the NO level was observed in NDV challenged chickens compared to the CON chickens at 2 dpi. The MDA contents were significantly increased whereas GSH was significantly decreased in NDV-challenged chickens compared to control. Furthermore, activities of GST, CAT, SOD, as well as the TOAC were markedly decreased in challenged chickens in comparison with control. Virus copy numbers were higher in NDV infected NS+CHA group compared to other groups. Severe histopathological changes including inflammation, degeneration and broken villi were observed in the intestine of NDV challenged chickens. However, all these malfunctions of antioxidant system and pathological changes in the intestine were partially or completely reversed by the vit. E supplementation. CONCLUSIONS: Our results suggest that NDV infection causes oxidative stress and histopathological changes in the duodenum and jejunum of chickens, which can be partially or fully ameliorated by supplementation of vit. E. Additionally, these findings suggest that oxidative stress contributes to the intestinal damages in NDV infected chickens. These findings will help to understand the pathogenesis of NDV and further investigation of therapeutic agents for control of Newcastle disease
Identification of the Genes Involved in Riemerella anatipestifer Biofilm Formation by Random Transposon Mutagenesis
Riemerella anatipestifer causes epizootics of infectious disease in poultry that result in serious economic losses to the duck industry. Our previous studies have shown that some strains of R. anatipestifer can form a biofilm, and this may explain the intriguing persistence of R. anatipestifer on duck farms post infection. In this study we used strain CH3, a strong producer of biofilm, to construct a library of random Tn4351 transposon mutants in order to investigate the genetic basis of biofilm formation by R. anatipestifer on abiotic surfaces. A total of 2,520 mutants were obtained and 39 of them showed a reduction in biofilm formation of 47%–98% using crystal violet staining. Genetic characterization of the mutants led to the identification of 33 genes. Of these, 29 genes are associated with information storage and processing, as well as basic cellular processes and metabolism; the function of the other four genes is currently unknown. In addition, a mutant strain BF19, in which biofilm formation was reduced by 98% following insertion of the Tn4351 transposon at the dihydrodipicolinate synthase (dhdps) gene, was complemented with a shuttle plasmid pCP-dhdps. The complemented mutant strain was restored to give 92.6% of the biofilm formation of the wild-type strain CH3, which indicates that the dhdp gene is associated with biofilm formation. It is inferred that such complementation applies also to other mutant strains. Furthermore, some biological characteristics of biofilm-defective mutants were investigated, indicating that the genes deleted in the mutant strains function in the biofilm formation of R. anatipestifer. Deletion of either gene will stall the biofilm formation at a specific stage thus preventing further biofilm development. In addition, the tested biofilm-defective mutants had different adherence capacity to Vero cells. This study will help us to understand the molecular mechanisms of biofilm development by R. anatipestifer and to study the pathogenesis of R. anatipestifer further
Prosedur penyelesaian pembiayaan bermasalah pada akad mudharabah dalam rangka meminimalisir resiko di BMT Amanah Usaha Mulia Magelang
Permasalah kehidupan perekonomian yang sulit, membuat masyarakat berinisiatif untuk membuka usaha sendiri. Mereka membutuhkan suatu bantuan berupa dana untuk memperlancar usahanya, maka BMT Amanah Usaha Mulia Magelang ikut untuk mengembangkan produknya yaitu pembiayaan mudharabah sesuai perkembangan dunia perbankan dalam target peningkatan keuntungan dan menyejahterakan masyarakat. Dengan diberikanya pembiayaan tersebut, terkadang muncul adanya pembiayaan bermasalah dikarenakan ada beberapa faktor diantaranya ketidakmampuan anggota untuk membayar tepat waktu atau jatuh tempo pembayaran diakibatkan karena usaha anggota yang kurang lancar dan lain sebagaianya.
Tugas Akhir ini berjudul “ Prosedur Penyelesaian Pembiayaan Bermasalah pada Akad Mudharabah Dalam Rangka Meminimalisir Risiko” Berdasarkan judul tersebut dapat diambil rumusan masalah yaitu apa penyebab terjadinya pembiayaan bermasalah pada BMT Amanah Usaha Mulia Magelang dan bagaimana prosedur penyelesaian pembiayaaan bermasalah pada akad mudharabah di BMT Amanah Usaha Mulia Magelang.
Penelitian ini merupakan penelitian lapangan dimana sumber data yang digunakan berasal dari data primer dan sekunder yang diperoleh melalui metode wawancara dengan manajer, bagian pembiayaan dan dokumentasi. Metode yang digunakan dalam penelitian ini adalah deskriptif kualitatif yang bertujuan untuk menggambarkan secara sistematis dan akurat mengenai objek penelitian.
Berdasarkan hasil penelitian dapat disimpulkan bahwa penyebab terjadinya pembiayaan bermasalah yaitu faktor internal meliputi kurang telitinya petugas BMT dalam menganalisi data calon anggota, kurang disiplinya dalam penagihan dan eksternal meliputi karakter anggota yang kurang baik, usahanya bangkrut dan terjadinya bencana alam yang tidak terduga. Adapun prosesdur yang digunakan BMT Amanah Usaha Mulia dalam menyelesaian pembiayaan bermasalah pada akad mudharabah dengan cara kekeluargaan atau musyawarah dengan anggota, penjadwalan kembali (rescheduling), persyaratan kembali (reconditioning), pengambilan jaminan (eksekusi), dan write off final. Di BMT Amanah Usaha Mulia dalam penyelesaian pembiayaan bermasalah jarang menngunakan jalur hukum, tetapi sering menggunakan cara kekeluargaan yang dianggap lebih efektif dan eksekusi jaminan apabila anggota tersebut sudah mengalami macet atau bermasalah
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