336 research outputs found

    Effect of Bond Thickness on Lifetime of Adhesive Joints

    Get PDF
    The aim of this research was to study the effect of bond thickness on the fracture energy and the lifetime of an adhesively bonded system and develop a model to predict the lifetime of adhesive joints. An approach based on fracture mechanics was employed to assess aluminum/epoxy bond lifetime. An experimental investigation was carried out using double cantilever beam (DCB) specimens with various bond thicknesses under mode 1. This study describes an approach to predict the rate of crack propagation using Paris\u27 power law. The approach used elevated temperatures to accelerate the crack propagation under constant loads. The elevated temperatures were kept below the glass transition of the adhesive. The general idea was to apply a constant load below the critical value to allow for measurable slow crack propagation. The fracture energy of the bonded joints was evaluated using both simple beam and beam on elastic foundation analyses. A simple model was proposed to predict the variation of the two kinetic parameters of Paris\u27 law as a function of bond thickness. A model was developed, which would enable crack propagation to be modeled and hence the lifetime of adhesive joints to be predicted

    Molecular detection of Treponema species organisms in foremilk and udder cleft skin of dairy cows with digital dermatitis

    Get PDF
    Identification of reservoirs and transmission routes of digital dermatitis (DD)-associated Treponema spp. is considered an effective means for controlling DD infection in dairy cows. The objective of this study is to identify and characterize the potential reservoir niches for DD-associated Treponema spp. from healthy udder cleft skin and foremilk in lactating dairy cows. A large dairy farm was visited weekly from March to July 2015. Clinical investigation revealed that a total of 25 lame cows had DD lesions located at the plantar aspect of the interdigital cleft. A total of 75 samples, three per cow, were collected including deep swabs from DD lesions (n = 25), non-aseptically collected foremilk samples (n = 25) and skin swabs from udder cleft (n = 25). Treponema spp. were identified using nested PCR assays and confirmed by DNA sequencing. Results revealed that Treponema phagedenis (T. phagedenis)-like was the most identified species in the foremilk 40% (10/25), in comparison with DD lesions and udder cleft skin samples with 32% (8/25) and 20% (5/25), respectively. On the other hand, Treponema pedis (T. pedis) was the most identified species in the udder cleft skin 80% (20/25), in comparison with DD lesions and foremilk samples with 68% (17/25) and 60% (15/25), respectively. None of the examined samples were identified by PCR as containing DNA from Treponema medium (T. medium) or Treponema vincentii (T. vincentii)-like. To the best of our knowledge, this is the first report for detection of T. phagedenis-like and T. pedis from healthy skin of udder cleft and foremilk samples. Detection of DD Treponema spp. from udder cleft skin and foremilk samples indicates that these sites could be potential reservoirs for spirochetes involved in DD. Udder cleft skin and foremilk may have a role in transmission routes of DD Treponema in dairy farms.info:eu-repo/semantics/acceptedVersio

    A distinct bacterial dysbiosis associated skin inflammation in ovine footrot

    Get PDF
    Ovine footrot is a highly prevalent bacterial disease caused by Dichelobacter nodosus and characterised by the separation of the hoof horn from the underlying skin. The role of innate immune molecules and other bacterial communities in the development of footrot lesions remains unclear. This study shows a significant association between the high expression of IL1β and high D. nodosus load in footrot samples. Investigation of the microbial population identified distinct bacterial populations in the different disease stages and also depending on the level of inflammation. Treponema (34%), Mycoplasma (29%) and Porphyromonas (15%) were the most abundant genera associated with high levels of inflammation in footrot. In contrast, Acinetobacter (25%), Corynebacteria (17%) and Flavobacterium (17%) were the most abundant genera associated with high levels of inflammation in healthy feet. This demonstrates for the first time there is a distinct microbial community associated with footrot and high cytokine expression

    Platelet-Rich Plasma Promotes the Proliferation of Human Muscle Derived Progenitor Cells and Maintains Their Stemness

    Get PDF
    Human muscle-derived progenitor cells (hMDPCs) offer great promise for muscle cell-based regenerative medicine; however, prolonged ex-vivo expansion using animal sera is necessary to acquire sufficient cells for transplantation. Due to the risks associated with the use of animal sera, the development of a strategy for the ex vivo expansion of hMDPCs is required. The purpose of this study was to investigate the efficacy of using platelet-rich plasma (PRP) for the ex-vivo expansion of hMDPCs. Pre-plated MDPCs, myoendothelial cells, and pericytes are three populations of hMDPCs that we isolated by the modified pre-plate technique and Fluorescence Activated Cell Sorting (FACS), respectively. Pooled allogeneic human PRP was obtained from a local blood bank, and the effect that thrombin-activated PRP-releasate supplemented media had on the ex-vivo expansion of the hMDPCs was tested against FBS supplemented media, both in vitro and in vivo. PRP significantly enhanced short and long-term cell proliferation, with or without FBS supplementation. Antibody-neutralization of PDGF significantly blocked the mitogenic/proliferative effects that PRP had on the hMDPCs. A more stable and sustained expression of markers associated with stemness, and a decreased expression of lineage specific markers was observed in the PRP-expanded cells when compared with the FBS-expanded cells. The in vitro osteogenic, chondrogenic, and myogenic differentiation capacities of the hMDPCs were not altered when expanded in media supplemented with PRP. All populations of hMDPCs that were expanded in PRP supplemented media retained their ability to regenerate myofibers in vivo. Our data demonstrated that PRP promoted the proliferation and maintained the multi-differentiation capacities of the hMDPCs during ex-vivo expansion by maintaining the cells in an undifferentiated state. Moreover, PDGF appears to be a key contributing factor to the beneficial effect that PRP has on the proliferation of hMDPCs. © 2013 Li et al

    Digital dermatitis in cattle is associated with an excessive innate immune response triggered by the keratinocytes

    Get PDF
    Background: Digital Dermatitis (DD) is a common disease of dairy cows, the pathogenesis of which is still not clear. This study examined some host responses associated with the typical lesions, in an attempt to further elucidate the pathogenesis of the disease. Twenty four samples representing the 5 different clinical stages of DD (M0-M4) were collected from slaughtered cattle for histopathological and immunological analyses. Results: Significant increases in total epidermal thickness were found in M2, M3, and M4 when compared with M0 and M1. M3 samples, when compared with M0 and M1, were characterized by a significant increase in the thickness of the keratin layer. Counts of both eosinophils and neutrophils were at a maximum in the M2 stage and decreased in the M3 and M4 stage. A significant increase in IL8 expression was observed in the M2-M3 stages of the disease and immunohistochemical staining showed the source as keratinocytes, suggesting an important role for keratinocyte-derived IL8 in the pathogenesis of DD. Conclusion: Results of the present study point to a strong stimulation of the innate immune response at the level of the keratinocytes throughout most of the clinical stages, and a delayed response of the adaptive immune reaction

    EFFECT OF HUMIC ACID, COMPOST AND BIOFERTILIZATION ON FRUITING OF SUPERIOR SEEDLESS GRAPEVINES

    Get PDF
    Superior grapevines fertilized with compost, biofertilizers namely (Bacillus megatherium, Bacillus curculanse and Azotoacter Chroococcum), humic acid and two slow release fertilizers namely ( rock phosphate and feldspar ) as a partial replacement of mineral N fertilizers during 2013 and 2014 seasons. Using all substitutes of mineral N fertilizers was favourable than using mineral N alone in enhancing all growth characters, total chlorophylls, nutrients, yield and berries characteristics. Both nitrite and nitrate in the juice were greatly declined in all N management treatments that included the application of all N sources. The best results with regards to yield and berries characteristics of Superior seedless grapevines were recorded on  vines that received 60g N, 60g P and 120g K/ vine/ year ( mineral sources) plus compost II ( 40% cattle manure + 60% rice straw ) at 16 kg./ vine+ the three biofertilizers namely Bacillus megatheium, Bacillus circulanse and Azotobacter chroococcum  + humic acid each at 10ml./ vine/ year

    Reverse Image Search Using Deep Unsupervised Generative Learning and Deep Convolutional Neural Network

    Get PDF
    Reverse image search has been a vital and emerging research area of information retrieval. One of the primary research foci of information retrieval is to increase the space and computational efficiency by converting a large image database into an efficiently computed feature database. This paper proposes a novel deep learning-based methodology, which captures channel-wise, low-level details of each image. In the first phase, sparse auto-encoder (SAE), a deep generative model, is applied to RGB channels of each image for unsupervised representational learning. In the second phase, transfer learning is utilized by using VGG-16, a variant of deep convolutional neural network (CNN). The output of SAE combined with the original RGB channel is forwarded to VGG-16, thereby producing a more effective feature database by the ensemble/collaboration of two effective models. The proposed method provides an information rich feature space that is a reduced dimensionality representation of the image database. Experiments are performed on a hybrid dataset that is developed by combining three standard publicly available datasets. The proposed approach has a retrieval accuracy (precision) of 98.46%, without using the metadata of images, by using a cosine similarity measure between the query image and the image database. Additionally, to further validate the proposed methodology’s effectiveness, image quality has been degraded by adding 5% noise (Speckle, Gaussian, and Salt pepper noise types) in the hybrid dataset. Retrieval accuracy has generally been found to be 97% for different variants of nois

    The Variations in the Level of Angiotensin II Between Subjects in Ajloun City and the Dead Sea Impact Hypertension Parameters

    Get PDF
    Introduction: Jordan has a unique array of diversity among which having the deepest level in the world, the Dead Sea and an area with high attitudes in Ajloun City which gives us a great chance to study the biological effects on hypertension and possible impacts in selecting the appropriate treatment. Study objectives: to explore the impacts of variations of attitudes in hypertension and the level of beta blockers through studying the level of angiotensin II among study participants and to investigate if the patterns of anti-hypertensive treatments are impacted. Methods and subjects: a cross-sectional study design was carried out among participants from the two different areas. From each area, a total of 500 participants were recruited and surveyed through a questionnaire. Blood pressure was measured for all participants and blood samples were withdrawn to carry out the testing of angiotensin II. Data were analyzed statistically based on the appropriate software including excel and SPSS. The relationships were examined according to independent T-Test. Significance was considered according to p0.05). On the other hand, heart parameters including SBP, DBP, MBP, pulse, and PCV all of which were significantly higher in Ajloun than in the Dead Sea (p=0.001) for all selected variables. The level of angiotensin II was 12.08 ± 5.19 pg/ml in Ajloun and this was higher than that of the Dead Sea (8.84 ± 4.65 pg/ml). The difference in the mean of angiotensin II was statistically significant (p=0.039). Conclusion: the results of the present study showed that living in high altitude compared with the lowest area in the world (the Dead Sea) exposes persons for the risks of hypertension and other cardiovascular diseases. Our findings may lead to better therapeutic strategies particularly when to prescribe angiotensin II based therapies

    INVESTIGATIN OF M. agalactiae AND STUDY ITS EFFECTS ON SOME HEMATOLOGICAL AND BIOCHEMICAL PARAMETERS IN SHEEP AND GOATS INFECTED WITH MASTITIS

    Get PDF
    This study was performed to investigate M. agalactiae as a cause of mastitis in sheep andgoat and study some hematological and biochemical parameters, for this aims (102) milksamples and (102) blood samples from mastitic sheep and goat were collected . our resultsshowed that detection of M. agalactiae in ratio of (10.87 %) and (16.6 % ) by culture andPCR technique. Regarding biochemical parameters we noted that zinc decrease significantly(P ≤ 0.05) in infected group, while copper, Total protein, Albumin and Globulin levels notaffected. As far as hematological parameters we noted no significant differences betweenInfected and Non Infected group in the level of WBC and Hb while significant decrease inthe level of RBC and PCV in infected group in compare with control group . we concludefrom this study M. agalactiae consider as one of mastitis cause in Salahaldeen province andit affects on hematological and biochemical parameters in studied group

    Synthetic rubber surface as an alternative to concrete to improve welfare and performance of finishing beef cattle reared on fully slatted flooring

    Get PDF
    open8noopenBrscic, M.; Ricci, R.; Prevedello, P.; Lonardi, C.; De Nardi, R.; Contiero, B.; Gottardo, F.; Cozzi, G.Brscic, Marta; Ricci, Rebecca; Prevedello, P.; Lonardi, Chiara; DE NARDI, Roberta; Contiero, Barbara; Gottardo, Flaviana; Cozzi, Giuli
    corecore