189 research outputs found
Dynamic Analysis of Disc Brake using Finite Element Method
In today’s scenario, the necessity of efficient transportation system puts manufacturers in a situation, where they cannot neglect the importance of improvement in safety systems. The brake system is one of the most crucial parts of the safety system. In previous research works, they have performed finite element analysis of disc brake mostly on ICEM-CFD CFX, structural analysis with structural boundary conditions and thermal analysis with thermal boundary conditions. But they didn’t show how that frictional heat generated when disc brake is rotating. So to perform that analysis we have to couple both thermal and structural analyses. And on ANSYS workbench, it is not possible to couple both without the help of User Defined Functions (UDF).
In this thesis, we tried to find out the temperature with some varying boundary conditions by ANSYS simulation techniques. The simulations were performed by using thermostructural 3D coupled-field analysis in the transient structural module of ANSYS 15.0 workbench. The analyses formulation was based on Augmented Lagrangian method. In this research work, we tried to analyse the temperature heat generation along with simultaneous cooling in the transient structural module. The analyses are performed using temperaturedependent material models with grey cast iron, ceramic Al2O3, and structural steel. For this work, we have used element type SOLID226. We assume that percentage of frictional dissipated energy converted into heat is 100%.
These simulation results find out one temperature profile hot band in the middle of the disc brake rotor where the pad is in contact with the rotor, which shows maximum temperature generated on the disc surface. These analyses show that we can also perform transient thermal analysis on the transient structural module with the use of some User-Defined Functions (UDF)
Importance of the ebp (endocarditis- and biofilm-associated pilus) locus in the pathogenesis of Enterococcus faecalis ascending urinary tract infection.
BACKGROUND: We recently demonstrated that the ubiquitous Enterococcus faecalis ebp (endocarditis- and biofilm-associated pilus) operon is important for biofilm formation and experimental endocarditis. Here, we assess its role in murine urinary tract infection (UTI) by use of wild-type E. faecalis OG1RF and its nonpiliated, ebpA allelic replacement mutant (TX5475).
METHODS: OG1RF and TX5475 were administered transurethrally either at an ~1 : 1 ratio (competition assay) or individually (monoinfection). Kidney pairs and urinary bladders were cultured 48 h after infection. These strains were also tested in a peritonitis model.
RESULTS: No differences were observed in the peritonitis model. In mixed UTIs, OG1RF significantly outnumbered TX5475 in kidneys (P=.0033) and bladders (P\u3c or =.0001). More OG1RF colony-forming units were also recovered from the kidneys of monoinfected mice at the 4 inocula tested (P=.015 to P=.049), and 50% infective doses of OG1RF for kidneys and bladder (9.1x10(1) and 3.5x10(3) cfu, respectively) were 2-3 log(10) lower than those of TX5475. Increased tropism for the kidney relative to the bladder was observed for both OG1RF and TX5475.
CONCLUSION: The ebp locus, part of the core genome of E. faecalis, contributes to infection in an ascending UTI model and is the first such enterococcal locus shown to be important in this site
Aggravation of cyclophosphamide-induced reproductive toxicity in mice by aqueous extract of Aegle marmelos (L.)
Aegle marmelos (L.) (Rutaceae) commonly known as bael is an important medicinal fruit tree. The present study focused on the effects of aqueous extract of Aegle marmelos (AEAM) on the testis and sperm characteristics induced by cyclophosphamide (CPA) in mice. Thirty six adult Parke’s strain mice were divided into six groups: group I given only distilled water (control); group II administered with AEAM alone once in a week for five weeks; group III administered with CPA (200 mg/kg b.w., intraperitoneally) once in a week for five weeks and group IV-VI CPA along with AEAM (400, 500 and 600 mg/kg b.w., orally). CPA was found to reduce gonadosomatic index (GSI), sperm counts, motility, viability, antioxidant activities and induced histopathological changes of testis. In the group administered AEAM with CPA an exacerbation of sperm count, motility and viability of the cauda epididymis, GSI, antioxidant activities and architecture of testis was observed. The results suggest that the administration of AEAM may aggravate CPA-induced reproductive toxicity. It may be helpful in preparation of natural male contraceptives
Post Harvest Technology of Papaya Fruits and It’S Value Added Products-A Review
Helicoverpa armigera (Hubner) is considered one of the most important pests in agriculture globally. As it is a polypahgous pest and infests more than 180 plants, it causes huge economic loss annually. It is a native to India and is widely distributed throughout the country. Agriculturists have taken several measures to control this pest. Earlier methods include the use of chemical pesticides and insecticides. In recent times, more attention is being paid to the biological control methods such as use of natural enemies, pheromones, neuropeptides, development of transgenic crops, RNA interference technology etc. These methods though have faced some challenges in implementation but are safe, sustainable and mostly species specific. Here, we have discussed the chemical and biological methods that have been used in the past or are currently in practice. We have also discussed some of quite recent but promising technologies which in future can be developed as a tool for the control of Helicoverpa armigera
Post Harvest Technology of Papaya Fruits and It’S Value Added Products-A Review
Helicoverpa armigera (Hubner) is considered one of the most important pests in agriculture globally. As it is a polypahgous pest and infests more than 180 plants, it causes huge economic loss annually. It is a native to India and is widely distributed throughout the country. Agriculturists have taken several measures to control this pest. Earlier methods include the use of chemical pesticides and insecticides. In recent times, more attention is being paid to the biological control methods such as use of natural enemies, pheromones, neuropeptides, development of transgenic crops, RNA interference technology etc. These methods though have faced some challenges in implementation but are safe, sustainable and mostly species specific. Here, we have discussed the chemical and biological methods that have been used in the past or are currently in practice. We have also discussed some of quite recent but promising technologies which in future can be developed as a tool for the control of Helicoverpa armige
Post Harvest Technology of Papaya Fruits and It’S Value Added Products-A Review
Helicoverpa armigera (Hubner) is considered one of the most important pests in agriculture globally. As it is a polypahgous pest and infests more than 180 plants, it causes huge economic loss annually. It is a native to India and is widely distributed throughout the country. Agriculturists have taken several measures to control this pest. Earlier methods include the use of chemical pesticides and insecticides. In recent times, more attention is being paid to the biological control methods such as use of natural enemies, pheromones, neuropeptides, development of transgenic crops, RNA interference technology etc. These methods though have faced some challenges in implementation but are safe, sustainable and mostly species specific. Here, we have discussed the chemical and biological methods that have been used in the past or are currently in practice. We have also discussed some of quite recent but promising technologies which in future can be developed as a tool for the control of Helicoverpa armigera
Flexible perylenediimide/GaN organic-inorganic hybrid system with exciting optical and interfacial properties
We report the band gap tuning and facilitated charge transport at perylenediimide (PDI)/GaN interface in organic-inorganic hybrid nanostructure system over flexible titanium (Ti) foil. Energy levels of the materials perfectly align and facilitate high efficiency charge transfer from electron rich n-GaN to electron deficient PDI molecules. Proper interface formation resulted in band gap tuning as well as facilitated electron transport as evident in I-V characteristics. Growth of PDI/GaN hybrid system with band gap tuning from ultra-violet to visible region and excellent electrical properties open up new paradigm for fabrication of efficient optoelectronics devices on flexible substrates
The hylEfm gene in pHylEfm of Enterococcus faecium is not required in pathogenesis of murine peritonitis
<p>Abstract</p> <p>Background</p> <p>Plasmids containing <it>hyl</it><sub><it>Efm </it></sub>(pHyl<sub>Efm</sub>) were previously shown to increase gastrointestinal colonization and lethality of <it>Enterococcus faecium </it>in experimental peritonitis. The <it>hyl</it><sub><it>Efm </it></sub>gene, predicting a glycosyl hydrolase, has been considered as a virulence determinant of hospital-associated <it>E. faecium</it>, although its direct contribution to virulence has not been investigated. Here, we constructed mutants of the <it>hyl</it><sub><it>Efm</it></sub>-region and we evaluated their effect on virulence using a murine peritonitis model.</p> <p>Results</p> <p>Five mutants of the <it>hyl</it><sub><it>Efm</it></sub>-region of pHyl<sub>EfmTX16 </sub>from the sequenced endocarditis strain (TX16 [DO]) were obtained using an adaptation of the PheS* system and were evaluated in a commensal strain TX1330RF to which pHyl<sub>EfmTX16 </sub>was transferred by mating; these include <it>i</it>) deletion of <it>hyl</it><sub><it>Efm </it></sub>only; <it>ii</it>) deletion of the gene downstream of <it>hyl</it><sub><it>Efm </it></sub>(<it>down</it>) of unknown function; <it>iii</it>) deletion of <it>hyl</it><sub><it>Efm </it></sub>plus <it>down</it>; <it>iv</it>) deletion of <it>hyl</it><sub><it>Efm</it></sub>-<it>down </it>and two adjacent genes; and <it>v</it>) a 7,534 bp deletion including these four genes plus partial deletion of two others, with replacement by <it>cat</it>. The 7,534 bp deletion did not affect virulence of TX16 in peritonitis but, when pHyl<sub>EfmTX16Δ7,534 </sub>was transferred to the TX1330RF background, the transconjugant was affected in <it>in vitro </it>growth versus TX1330RF(pHyl<sub>EfmTX16</sub>) and was attenuated in virulence; however, neither <it>hyl</it><sub><it>Efm </it></sub>nor <it>hyl</it><sub><it>Efm</it></sub>-<it>down </it>restored wild type function. We did not observe any <it>in vivo </it>effect on virulence of the other deletions of the <it>hyl</it><sub><it>Efm</it></sub>-region</p> <p>Conclusions</p> <p>The four genes of the <it>hyl</it><sub><it>Efm </it></sub>region (including <it>hyl</it><sub><it>Efm</it></sub>) do not mediate the increased virulence conferred by pHyl<sub>EfmTX16 </sub>in murine peritonitis. The use of the markerless counterselection system PheS* should facilitate the genetic manipulation of <it>E. faecium </it>in the future.</p
Cryo-electron Microscopy Structure of the 70S Ribosome from Enterococcus faecalis
Enterococcus faecalis is a gram-positive organism responsible for serious infections in humans, but as with many bacterial pathogens, resistance has rendered a number of commonly used antibiotics ineffective. Here, we report the cryo-EM structure of the E. faecalis 70S ribosome to a global resolution of 2.8 Å. Structural differences are clustered in peripheral and solvent exposed regions when compared with Escherichia coli, whereas functional centres, including antibiotic binding sites, are similar to other bacterial ribosomes. Comparison of intersubunit conformations among five classes obtained after three-dimensional classification identifies several rotated states. Large ribosomal subunit protein bL31, which forms intersubunit bridges to the small ribosomal subunit, assumes different conformations in the five classes, revealing how contacts to the small subunit are maintained throughout intersubunit rotation. A tRNA observed in one of the five classes is positioned in a chimeric pe/E position in a rotated ribosomal state. The 70S ribosome structure of E. faecalisnow extends our knowledge of bacterial ribosome structures and may serve as a basis for the development of novel antibiotic compounds effective against this pathogen
The Fibronectin-Binding Protein Fnm Contributes to Adherence to Extracellular Matrix Components and Virulence of Enterococcus faecium
The interaction between bacteria and fibronectin is believed to play an important role in the pathogenicity of clinically important Gram-positive cocci. In the present study, we identified a gene encoding a predicted fibronectin-binding protein of Enterococcus faecium (fnm), a homologue of Streptococcus pneumoniae pavA, in the genomes of E. faecium strain TX82 and all other sequenced E. faecium isolates. Full-length recombinant Fnm from strain TX82 bound to immobilized fibronectin in a concentration-dependent manner and also appeared to bind collagen type V and laminin, but not other proteins, such as transferrin, heparin, bovine serum albumin, mucin, or collagen IV. We demonstrated that the N-terminal fragment of Fnm is required for full fibronectin binding, since truncation of this region caused a 2.4-fold decrease (P < 0.05) in the adhesion of E. faecium TX82 to fibronectin. Deletion of fnm resulted in a significant reduction (P < 0.001) in the ability of the mutant, TX6128, to bind fibronectin relative to that of the wild-type strain; in situ reconstitution of fnm in the deletion mutant strain restored adherence. In addition, the Δfnm mutant was highly attenuated relative to TX82 (P ≤ 0.0001) in a mixed-inoculum rat endocarditis model. Taken together, these results demonstrate that Fnm affects the adherence of E. faecium to fibronectin and is important in the pathogenesis of experimental endocarditis
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