Journal articles: 'CLFV'

1

Cei, F., and D. Nicolò. "Lepton Flavour Violation Experiments." Advances in High Energy Physics 2014 (2014): 1–31. http://dx.doi.org/10.1155/2014/282915.

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Lepton Flavour Violation in the charged lepton sector (CLFV) is forbidden in the Minimal Standard model and strongly suppressed in extensions of the model to include finite neutrino mixing. On the other hand, a wide class of Supersymmetric theories, even coupled with Grand Unification models (SUSY-GUT models), predict CLFV processes at a rate within the reach of new experimental searches operated with high resolution detectors at high intensity accelerators. As the Standard model background is negligible, the observation of one or more CLFV events would provide incontrovertible evidence for physics beyond Standard model, while a null effect would severely constrain the set of theory parameters. Therefore, a big experimental effort is currently (and will be for incoming years) accomplished to achieve unprecedented sensitivity on several CLFV processes. In this paper we review past and recent results in this research field, with focus on CLFV channels involving muons and tau's. We present currently operating experiments as well as future projects, with emphasis laid on how sensitivity enhancements are accompanied by improvements on detection techniques. Limitations due to systematic effects are also discussed in detail together with the solutions being adopted to overcome them.

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Pikies, M. "cLFV Searches at LHCb." Acta Physica Polonica B 49, no. 6 (2018): 1309. http://dx.doi.org/10.5506/aphyspolb.49.1309.

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Mihara, S. "Prospects for CLFV experiments." Journal of Physics: Conference Series 408 (February 7, 2013): 012017. http://dx.doi.org/10.1088/1742-6596/408/1/012017.

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4

Hitlin, David G. "CLFV Decays at BaBar." Nuclear Physics B - Proceedings Supplements 248-250 (March 2014): 64–66. http://dx.doi.org/10.1016/j.nuclphysbps.2014.02.012.

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Paradisi, Paride. "Interrelationship among , EDMs and cLFV." Nuclear Physics B - Proceedings Supplements 248-250 (March 2014): 8–12. http://dx.doi.org/10.1016/j.nuclphysbps.2014.02.003.

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Kriewald, J., A. Abada, and A. M. Teixeira. "The role of leptonic CPV phases in cLFV observables." Journal of Physics: Conference Series 2156, no. 1 (December 1, 2021): 012154. http://dx.doi.org/10.1088/1742-6596/2156/1/012154.

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Abstract In models where the Standard Model is extended by Majorana fermions, interference effects due to the presence of CP violating phases have been shown to play a crucial role in lepton number violating processes. However, important effects can also arise in lepton number conserving, but charged lepton flavour violating (cLFV) transitions and decays. Here we show that the presence of CP violating (Dirac and Majorana) phases can have a striking impact for the predicted rates of cLFV observables. We explore the interference effects in several cLFV observables, carrying for the first time a thorough analysis of the different observables and the implications for future observation. We discuss how the presence of leptonic CP violating phases might lead to a loss of correlation between observables (typically present in simple SM extensions via heavy sterile fermions), or even to the suppression of certain channels; these effects can be interpreted as suggestive of non-vanishing phases.

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Natori, Hiroaki. "COMET, an Experiment to Search for mu-e Conversion in a Nuclear Field." International Journal of Modern Physics: Conference Series 46 (January 2018): 1860065. http://dx.doi.org/10.1142/s2010194518600650.

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Charged lepton flavor violating (CLFV) process is predicted to be out of experimental reach by the Standard Model of elementary particle physics (SM). However, many models of the new physics beyond the SM predicts that it is just below the current experimental limit. COMET searches for one of the CLFV process, mu-e conversion in a nuclear field, improving the sensitivity by a factor of approximately [Formula: see text] for Phase-I and [Formula: see text] for Phase-II experiment from a past experiment.

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Hambye, Thomas. "CLFV and the origin of neutrino masses." Nuclear Physics B - Proceedings Supplements 248-250 (March 2014): 13–19. http://dx.doi.org/10.1016/j.nuclphysbps.2014.02.004.

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Shoukavy, Dzmitry. "COMET status and plans." EPJ Web of Conferences 212 (2019): 01006. http://dx.doi.org/10.1051/epjconf/201921201006.

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Lepton Flavour Violation in the charged lepton sector (CLFV) is forbidden in the Standard Model. Therefore, the observation of CLFV process would be clear evidence of physics beyond the Standard Model. The COMET (COherent Muon to Electron Transitions) experiment will measure one of these processes: µN → eN at the Japan Proton Accelerator Research Complex in Tokai, Japan. The COMET experiment will be carried out using a two-staged approach. Phase-I of the experiment is aiming at a signal sensitivity of 3.1 × 10−15. Phase-II will use much more intense beam and a more complex transport system to achieve a single-event sensitivity of 3 × 10−17. The article gives an overview of construction and status of the COMET experiment.

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Jasien, Paul G. "Stabilities of hypervalent chlorine fluorides (ClF3, ClF5 and ClF7)." Chemical Physics Letters 188, no. 1-2 (January 1992): 135–39. http://dx.doi.org/10.1016/0009-2614(92)85102-g.

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11

Papa, Angela. "Charged lepton flavour violation searches at the Paul Scherrer Institut: Status of the MEGII and Mu3e experiments." EPJ Web of Conferences 179 (2018): 01018. http://dx.doi.org/10.1051/epjconf/201817901018.

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The MEG experiment has recently set a new upper limit on the branching ratio of the μ+ → e+γ decay, B(μ+ → e+γ) < 4.2 × 10-13 (at 90% confidence level) and un upgrade of the experiment (the MEGII experiment) is ongoing with the aim of improving the single event sensitivity (SES) by one order of magnitude with respect to the previous MEG experiment’s SES. The strong scientific motivation associated with the charged Lepton Flavour Violation (cLFV) searches pushes also towards searching for the complementary muon cLFV μ+ → e+e+e- decay with the Mu3e experiment aiming at a SES improved by at least three orders of magnitude with respect to the previous SINDRUM experiment’s SES (phase I) up to an ultimate SES of few ×10-16. Both experiments will be hosted at the Paul Scherrer Institut which delivers the most intense continuous low energy muon beam in the world up to few ×108 μ/s. The status of both the MEGII and Mu3e experiments is given.

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Papa, Angela. "Towards a new generation of Charged Lepton Flavour Violation searches at the Paul Scherrer Institut: The MEG upgrade and the Mu3e experiment." EPJ Web of Conferences 234 (2020): 01011. http://dx.doi.org/10.1051/epjconf/202023401011.

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The MEG experiment has recently set a new upper limit on the branching ratio of the µ+ → e+γ decay, ℬ(µ+ → e+γ) < 4.2 × 10−13 (at 90% confidence level) and un upgrade of the experiment (the MEGII experiment) is ongoing with the aim of improving the single event sensitivity (SES) by one order of magnitude with respect to the previous MEG experiment’s SES. The strong scientific motivation associated with the charged Lepton Flavour Violation (cLFV) searches pushes also towards searching for the complementary muon cLFV µ+ → e+e+e− decay with a completely new apparatus, the Mu3e experiment, aiming at a SES improved by at least three orders of magnitude with respect to the previous SINDRUM experiment’s SES (Mu3e phase I). An ultimate SES of few ×10−16 is foreseen requiring 109 µ/s (Mu3e phase II). Both experiments will be hosted at the Paul Scherrer Institut which currently delivers the most intense continuous low energy muon beam in the world up to few ×108 µ/s. The status of both the MEGII and Mu3e phase I experiments is given.

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Lee, MyeongJae, and Michael MacKenzie. "Muon to Positron Conversion." Universe 8, no. 4 (April 7, 2022): 227. http://dx.doi.org/10.3390/universe8040227.

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Lepton-flavor violation (LFV) has been discovered in the neutrino sector by neutrino oscillation experiments. The minimal extension of the Standard Model (SM) to include neutrino masses allows LFV in the charged sector (CLFV) at the loop level, but at rates that are too small to be experimentally observed. Lepton-number violation (LNV) is explicitly forbidden even in the minimally extended SM, so the observation of an LNV process would be unambiguous evidence of physics beyond the SM. The search for the LNV and CLFV process μ−+N(A,Z)→e++N′(A,Z−2) (referred to as μ−→e+) complements 0νββ decay searches, and is sensitive to potential flavor effects in the neutrino mass-generation mechanism. A theoretical motivation for μ−→e+ is presented along with a review of the status of past μ−→e+ experiments and future prospects. Special attention is paid to an uncertain and potentially dominant background for these searches, namely, radiative muon capture (RMC). The RMC high energy photon spectrum is theoretically understudied and existing measurements insufficiently constrain this portion of the spectrum, leading to potentially significant impacts on current and future μ−→e+ work.

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Takeuchi, Michihisa, Yuichi Uesaka, and Masato Yamanaka. "Higgs mediated CLFV processes μN ( eN )→ τX via gluon operators." Physics Letters B 772 (September 2017): 279–82. http://dx.doi.org/10.1016/j.physletb.2017.06.054.

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15

Thuc, Truong Trong, Le Tho Hue, Dinh Phan Khoi, and Nguyen Thanh Phong. "One Loop Corrections to Decay $\tau\rightarrow \mu\gamma$ in Economical 3-3-1 Model." Communications in Physics 25, no. 2 (September 1, 2015): 113. http://dx.doi.org/10.15625/0868-3166/25/2/5963.

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Lepton flavor violating (cLFV) decays of charged leptons such as $\tau\rightarrow \mu\gamma$, $\tau\rightarrow e\gamma$, $\mu\rightarrow e\gamma$,..., are now the subjects of experiments as signals of new Physics beyond the Standard Model (SM). In the limit of the unitary gauge, we prove that contributions from one loop corrections to the above decays are very small in the framework of the economical 3-3-1 model.

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16

Kim, Hyung Don, Ji Yeon Lee, Jeong-Yong Park, Dong Hwi Kim, Min Hye Kang, Hyun-A. Seong, Kyung Hye Seo, and Yun-Jeong Ji. "Neuroprotective Effects of Coreopsis lanceolata Flower Extract against Oxidative Stress-Induced Apoptosis in Neuronal Cells and Mice." Antioxidants 10, no. 6 (June 12, 2021): 951. http://dx.doi.org/10.3390/antiox10060951.

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(1) Background: Coreopsis lanceolata L. is a perennial plant of the family Asteraceae, and its flower is known to contain flavonoids with various bioactivities. We evaluated the effect of Coreopsis lanceolata L. flower (CLF) extracts on H2O2-induced oxidative stress (OS) in neuronal cells and mouse neurons. (2) Methods: The flowering part of CL was used as CLF1 (70% ethanol extract) and CLF2 (water extract), and 10 types of phenolic compounds were quantified using high-performance liquid chromatography. To evaluate the neuroprotective effects of CLF, the antioxidant activities of the extracts were measured, and the expression levels of antioxidant enzymes and proteins related to OS-induced apoptosis in neuronal cells and mouse neurons treated with the extracts were investigated. (3) Results: In the in vitro study, CLF ameliorated H2O2-induced oxidative stress and induced the expression of antioxidant enzymes in PC12 cells. Furthermore, CLF1 enhanced the expression of the Bcl-xL protein but reduced the expression of Bax and the cleavage of caspase-3. In the same manner, CLF1 showed neuroprotective effects against OS in vivo. Pretreatment with CLF1 (200 mg/kg) increased the Bcl-2 protein and decreased Bax compared with the 1-methyl-4-phenylpyridinium ion (MPP+)-treated C57BL/6 mice model group. Our results suggest that the protective effects of CLF1 on MPP+-induced apoptosis may be due to its anti-apoptotic activity, through regulating the expression of the Bcl-2 family. (4) Conclusions: CLF1 exerts neuroprotective effects against OS-induced apoptosis in PC12 cells in a Parkinson’s disease model mouse. This effect may be attributable to the upregulation of Bcl-2 protein expression, downregulation of Bax expression, and inhibition of caspase-3 activation. These data indicate that CLF may provide therapeutic value for the treatment of progressive neurodegenerative diseases.

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Hino, Y., Y. Kuno, A. Sato, H. Sakamoto, Y. Matsumoto, N. H. Tran, I. H. Hashim, et al. "A Highly intense DC muon source, MuSIC and muon CLFV search." Nuclear Physics B - Proceedings Supplements 253-255 (August 2014): 206–7. http://dx.doi.org/10.1016/j.nuclphysbps.2014.09.051.

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18

Miscetti, Stefano. "Status of the Mu2e experiment at Fermilab." EPJ Web of Conferences 234 (2020): 01010. http://dx.doi.org/10.1051/epjconf/202023401010.

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The Mu2e experiment aims to improve, by four orders of magnitude, current sensitivity in the search for the charged-lepton flavor violating (cLFV) neutrino-less conversion of a negative muon into an electron. The conversion process will be identified by a distinctive signature of a mono-energetic electron with energy slightly below the muon rest mass. In the Standard Model this process has a negligible rate. However, in many Beyond the Standard Model scenarios its rate is within the reach of Mu2e sensitivity. In this paper, we explain the Mu2e design guidelines and summarize the status of the experiment.

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19

Kettle, Peter-Raymond. "The “Golden” cLFV channels μ → eγ and μ → eee — the high-intensity frontier." Hyperfine Interactions 214, no. 1-3 (February 26, 2013): 47–54. http://dx.doi.org/10.1007/s10751-013-0789-6.

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20

Gomes, A. R., S. Vinga, M. Zavolan, and H. de Lencastre. "Analysis of the Genetic Variability of Virulence-Related Loci in Epidemic Clones of Methicillin-Resistant Staphylococcus aureus." Antimicrobial Agents and Chemotherapy 49, no. 1 (January 2005): 366–79. http://dx.doi.org/10.1128/aac.49.1.366-379.2005.

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ABSTRACT Methicillin-resistant Staphylococcus aureus (MRSA) isolates have previously been classified into major epidemic clonal types by pulsed-field gel electrophoresis in combination with multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec typing. We aimed to investigate whether genetic variability in potentially polymorphic domains of virulence-related factors could provide another level of differentiation in a diverse collection of epidemic MRSA clones. The target regions of strains representative of epidemic clones and genetically related methicillin-susceptible S. aureus isolates from the 1960s that were sequenced included the R domains of clfA and clfB; the D, W, and M regions of fnbA and fnbB; and three regions in the agr operon. Sequence variation ranged from very conserved regions, such as those for RNAIII and the agr interpromoter region, to the highly polymorphic R regions of the clf genes. The sequences of the clf R domains could be grouped into six major sequence types on the basis of the sequences in their 3′ regions. Six sequence types were also observed for the fnb sequences at the amino acid level. From an evolutionary point of view, it was interesting that a small DNA stretch at the 3′ clf R-domain sequence and the fnb sequences agreed with the results of MLST for this set of strains. In particular, clfB R-domain sequences, which had a high discriminatory capacity and with which the types distinguished were congruent with those obtained by other molecular typing methods, have potential for use for the typing of S. aureus. Clone- and strain-specific sequence motifs in the clf and fnb genes may represent useful additions to a typing methodology with a DNA array.

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Gritsenko, V. A., A. R. Mavzyutov, T. M. Pashkova, O. L. Kartashova, Ya V. Tyapaeva, and Yu P. Belozertseva. "GENETIC PROFILE STAPHYLOCOCCUS AUREUS, ISOLATED FROM BACTERIAL CARRIERS AND PATIENTS WITH INFECTIOUS INFLAMMATORY PATHOLOGY." Journal of microbiology epidemiology immunobiology, no. 4 (August 28, 2018): 56–62. http://dx.doi.org/10.36233/0372-9311-2018-4-56-62.

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Aim. A comparative genetic evaluation of the pathogenic potential of Staphylococcus aureus strains isolated from bacterial carriers and patients with infectious inflammatory pathology. Materials and methods. The presence of pathogenicity genes (ssp, spa, clfA and clfB) in 163 strains of S. aureus isolated from the mucous membrane of the nasal cavity of bacterial carriers, from the vaginal discharge of women with uterine myoma, the contents of the pustules of newborns with perinatal pyoderma, and the transudate of venous-trophic ulcers lower limbs and purulent wounds in patients with diabetic foot syndrome. Results. It was shown that the frequency of occurrence of ssp, spa, clfA and clfB genes in clinical strains of S. aureus depended on the source of their isolation. In all cultures of S. aureus (except vaginal isolates), the most common gene was ssp (in 66.7 - 94.6% of cases), which was found isolated or in different combinations with other genes (spa, clfA, clfB). It has been established that the genetic profiles of strains of S. aureus isolated from bacterial carriers and patients with infectious inflammatory pathology (perinatal pyoderma, purulent wounds in diabetic foot syndrome) show a pronounced similarity in the presence of ssp, spa, clfA and clfB genes. Conclusion. The possible role of asymptomatic carriage of strains of S. aureus with a pathogenic potential in the development of endogenous infections of different localization is discussed.

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Miajlovic, Helen, Anthony Loughman, Marian Brennan, Dermot Cox, and Timothy J. Foster. "Both Complement- and Fibrinogen-Dependent Mechanisms Contribute to Platelet Aggregation Mediated by Staphylococcus aureus Clumping Factor B." Infection and Immunity 75, no. 7 (April 16, 2007): 3335–43. http://dx.doi.org/10.1128/iai.01993-06.

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ABSTRACT Staphylococcus aureus can stimulate activation and aggregation of platelets, which are thought to be factors in the development of infective endocarditis. Previous studies have identified clumping factor A (ClfA) and fibronectin binding proteins A and B (FnBPA and FnBPB) as potent platelet aggregators. These proteins are able to stimulate rapid platelet aggregation by either a fibrinogen- or a fibronectin-dependent process which also requires antibodies specific to each protein. Slower aggregation has been seen in other systems where specific fibrinogen binding ligands are absent and platelet aggregation is mediated by complement and specific antibodies. Bacteria expressing ClfB aggregate platelets with a longer lag time than ClfA or FnBPA and FnBPB. In order to investigate whether ClfB causes platelet aggregation in a complement- or fibrinogen-dependent manner, a non-fibrinogen-binding mutant of ClfB (ClfB Q235A) was constructed. Lactococcus lactis expressing ClfB Q235A was able to stimulate platelet aggregation in platelet-rich plasma without a significant increase in lag time. The requirements for platelet aggregation were investigated using gel-filtered platelets. Fibrinogen and specific anti-ClfB antibodies were found to be sufficient to allow platelet aggregation mediated by the wild-type ClfB protein. It seems that ClfB causes platelet aggregation by a fibrinogen-dependent mechanism. The non-fibrinogen-binding ClfB mutant was unable to stimulate platelet aggregation under these conditions. However, bacteria expressing ClfB Q235A caused platelet aggregation in a complement-dependent manner which required specific anti-ClfB antibodies.

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Takahashi, Yoshinao, Korehito Kato, and Hitoshi Habuka. "Development of SiC Etching by Chlorine Fluoride Gas." Materials Science Forum 1004 (July 2020): 731–37. http://dx.doi.org/10.4028/www.scientific.net/msf.1004.731.

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Amorphous SiC and 4H-SiC were etched by chlorine fluoride (ClF), chlorine trifluoride (ClF3), fluorine (F2) and chlorine (Cl2) gases, in order to evaluate the etching capability of various reactive gases. The gaseous byproducts of SiC etching were observed by the quadrupole mass spectrometry. The ClF showed slow etching rate of amorphous SiC and 4H-SiC, while ClF3 and F2 quickly etched them. By the ClF gas, the etching rate of amorphous SiC was 120 nm/min at 400 °C. The ClF gas was expected to be suitable for a shallow etching, because of its moderate etching rate even at high temperatures.

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Kalashnikova, Viktoriya. "Pathogenic potential of Staphylococcus aureus colonizing the nasal cavity and lungs of monkeys." Russian veterinary journal 2020, no. 5 (November 25, 2020): 21–26. http://dx.doi.org/10.32416/2500-4379-2020-5-21-26.

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In this paper, data are presented on the study of genetic determinants of pathogenicity in S. aureus isolated from the respiratory tract of monkeys (nasal cavity and lungs) collected during 2017‒2019. The aim of this work is to determine some genes of pathogenicity and their combinations in S. aureus isolated from the nasal cavity of clinically healthy monkeys and from the lungs of monkeys that died from pneumonia. There was a high frequency of detection of adhesion genes (fnBpA ― 74.4 %, fnBpB ― 79.1 %, clfA ― 95.4 %, clfB ― 95.4 %), hemolysins (hla ― 83.7 %, hlb ― 81.4 %), Panton-Valentine leukocidin (pvl ― 48.1 %), which are regarded as markers of the increased pathogenicity of the microbe, as well as combinations of various genovariants. The hemolysin α gene was detected more often in S. aureus isolated from the lungs of monkeys with pneumonia (87.4 %), and the hemolysin β gene was found in almost all S. aureus isolated from the nasal cavity (96.2 %). Genes for fibronectin-binding proteins (fnBpA/B) were found with a high frequency in isolates detected from the nasal cavity, while the clumping factor gene (clfA/B) were isolated in 100 % of S. aureus studied. The genovariant hla-hlb-fnBpA-fnBpB-clfA-clfB was detected in almost half of the isolates (48.1%), the presence of all studied pathogenicity determinants (pvl-hla-hlb-fnBpA-fnBpB-clfA-clfB) was noted in 24.8 % S. aureus. Analysis of the high frequency of prevalence of genes responsible for the expression of pathogenicity factors confirms the pathogenicity of studied S. aureus isolates, detected in monkeys. Most of the isolates belonged to group IV of the regulatory gene (55.8%) and agr I takes second place (40.8 %). PCR detection of pvl, hla, hlb, fnBpA, fnBpB, clfA, clfB genes can be used to demonstrate the pathogenicity of S. aureus isolates from various animal biomaterials and serve as a criterion for epidemiological assessment in studying the S. aureus circulation in monkeys kept in captivity.

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Deivanayagam, Champion C. S., Samuel Perkins, Sita Danthuluri, Rick T. Owens, Todd Bice, Tamanna Nanavathy, Timothy J. Foster, Magnus Höök, and Sthanam V. L. Narayana. "Crystallization of ClfA and ClfB fragments: the fibrinogen-binding surface proteins of Staphylococcus aureus." Acta Crystallographica Section D Biological Crystallography 55, no. 2 (February 1, 1999): 554–56. http://dx.doi.org/10.1107/s0907444998012426.

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Recombinant constructs encoding the fibrinogen-binding domains of ClfA and ClfB from Staphylococcus aureus have been crystallized. ClfA was crystallized in the orthorhombic space group P212121 with unit-cell parameters a = 39.58, b = 81.39 and c = 112.65 Å. A complete data set was recorded to 2.1 Å resolution and had a Vm of 2.3 Å3 Da−1 with 46.5% solvent, suggesting one molecule per asymmetric unit. Co-crystals of ClfA with the 17 amino-acid C-terminal peptide of fibrinogen γ-chain diffracted to 2.1 Å resolution and had unit-cell parameters a = 39.11, b = 81.39 and c = 109.51 Å in the space group P212121. ClfB was crystallized in the tetragonal space group P41212 or P43212 with unit-cell parameters a = 96.31, b = 96.31 and c = 84.13 Å and diffracted to 2.45 Å resolution. The estimated Vm of 2.6 Å3 Da−1 with 53% solvent indicated one molecule in the asymmetric unit.

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Ye, Zhijian, Fanhe Kong, Baocheng Zhang, Wei Gao, and Jianfeng Mao. "A Method Framework for Automatic Airspace Reconfiguration-Monte Carlo Method for Eliminating Irregular Sector Shapes Generated by Region Growth Method." Sensors 19, no. 18 (September 12, 2019): 3934. http://dx.doi.org/10.3390/s19183934.

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With the growth of air traffic demand in busy airspace, there is an urgent need for airspace sectorization to increase air traffic throughput and ease the pressure on controllers. The purpose of this paper is to develop a method framework that can perform airspace sectorization automatically, reasonably, which can be used as an advisory tool for controllers as an automatic system, especially for eliminating irregular sector shapes generated by simulated annealing algorithm (SAA) based on the region growth method. The two graph cutting method, dynamic Monte Carlo method by changing location of flexible vertices (MC-CLFV) and Monte Carlo method by radius changing (MC-RC) were developed to eliminate irregular sector shapes generated by SAA in post-processing. The experimental results show that the proposed method framework of airspace sectorization (AS) can automatically and reasonably generate sector design schemes that meet the design criteria. Our methodology framework and software can provide assistant design and analysis tools for airspace planners to design airspace, improve the reliability and efficiency of airspace design, and reduce the burden of airspace planners. In addition, this lays the foundation for reconstructing airspace with the more intelligent method.

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Papoulias, D. K., and T. S. Kosmas. "Studying background processes of the exotic neutrino-nucleus reactions." HNPS Proceedings 21 (March 8, 2019): 11. http://dx.doi.org/10.12681/hnps.1998.

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The background processes of the flavour changing neutral current (FCNC) processes, predicted by various new-physics models to occur in the presence of nuclei, are examined by computing the relevant nuclear matrix elements within the context of the quasi-particle RPA using realistic strong two-body forces. Our main goal is to explore the role of the non-standard interactions (NSI) in the leptonic sector and specifically: (i) in lepton flavour violating (LFV) processes involving neutrinos νl and ν ̃l, l = e, μ, τ and (ii) in charged lepton flavour violating (cLFV) processes involving the charged leptons l− or l+. As concrete nuclear system we have chosen the stopping target of μ− → e− conversion experiment, i.e. the 48Ti nucleus of the PRIME/PRISM experiment at J-PARC. This experiment has been designed to reduce the single event sensitivity down to 10−16–10−18 in searching for charged lepton mixing events. We also present, stringent constraints on the flavour violating parameters entering the NSI Lagrangians that have been obtained by taking advantage of our detailed nuclear structure calculations and exploiting the present limits or the sensitivity of the proposed exotic μ− → e− experiments.

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Atanov, N., V. Baranov, L. Borrel, C. Bloise, J. Budagov, S. Ceravolo, F. Cervelli, et al. "Towards the construction of the Mu2e electromagnetic calorimeter at Fermilab." Journal of Physics: Conference Series 2374, no. 1 (November 1, 2022): 012021. http://dx.doi.org/10.1088/1742-6596/2374/1/012021.

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Mu2e will search for the Charge Lepton Flavor Violating (CLFV) conversion of a muon into an electron in the field of a nucleus. A clean discovery signature is provided by the mono-energetic conversion electron (Ee = 104.96 MeV). If no events are observed, Mu2e will set a limit on the ratio between the conversion and the nuclear capture rate below 3 × 10−17 (at 90% C.L.). In order to confirm that the observed candidate is an electron, the calorimeter resolution requirements are to provide Eres < 10%, Tres < 500 ps for 100 MeV electrons while working in vacuum and in a high radiation environment and high magnetic field. The calorimeter is made of two annular aluminum disks, each one filled with 674 pure CsI crystals read out by SiPMs. A sophisticated mechanics and cooling system has been developed to support the crystals and cool the sensors. Radiation hard analog and fast digital electronics have been developed. In this paper the QC tests performed on the produced components and the construction status are reported, as well as the results obtained on the large size prototype with test beam data and at a cosmic ray test stand.

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Scharf, Peter, and Reinhart Ahlrichs. "Geometry and binding energy of ClF and ClF3." Chemical Physics 100, no. 2 (December 1985): 237–42. http://dx.doi.org/10.1016/0301-0104(85)85006-0.

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30

Ghosh, Gayatri, and Kalpana Bora. "Effects of Leptonic Nonunitarity on Lepton Flavor Violation, Neutrino Oscillation, Leptogenesis, and Lightest Neutrino Mass." Advances in High Energy Physics 2018 (June 25, 2018): 1–10. http://dx.doi.org/10.1155/2018/5093251.

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Neutrino physics is a mature branch of science with all the three neutrino mixing angles and two mass squared differences determined with high precision. In spite of several experimental verifications of neutrino oscillations and precise measurements of two mass squared differences and the three mixing angles, the unitarity of the leptonic mixing matrix is not yet established, leaving room for the presence of small nonunitarity effects. Deriving the bounds on these nonunitarity parameters from existing experimental constraints, on cLFV decays such as μ→eγ, μ→τγ, and τ→eγ, we study their effects on the generation of baryon asymmetry through leptogenesis and neutrino oscillation probabilities. We consider a model where see-saw is extended by an additional singlet S which is very light but can give rise to nonunitarity effects without affecting the form on see-saw formula. We do a parameter scan of a minimal see-saw model in a type I see-saw framework satisfying the Planck data on baryon to photon ratio of the Universe, which lies in the interval 5.8×10-10<YB<6.6×10-10(BBN). We predict values of lightest neutrino mass and Dirac and Majorana CP-violating phases δCP, α, and β, for normal hierarchy and inverted hierarchy for one-flavor leptogenesis. It is worth mentioning that all these four quantities are unknown yet, and future experiments will be measuring them.

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Serray, Bahija, Salwa Oufrid, Imane Hannaoui, Fatna Bourjilate, Nabila Soraa, Mostafa Mliji, Mohammed Sobh, Abderrahmane Hammoumi, Mohammed Timinouni, and Mohamed El Azhari. "Genes encoding adhesion factors and biofilm formation in methicillin-resistant Staphylococcus aureus in Morocco." Journal of Infection in Developing Countries 10, no. 08 (August 31, 2016): 863–69. http://dx.doi.org/10.3855/jidc.8361.

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Introduction: Infections involving methicillin-resistant Staphylococcus aureus (MRSA) remain a serious threat to hospitalized patients worldwide. MRSA is characterized by recalcitrance to antimicrobial therapy, which is a function not only of widespread antimicrobial resistance, but also the capacity to form biofilms. The present study evaluated the presence of genes encoding adhesion factors and the biofilm-forming capacity in MRSA. Methodology: In this study, 53 isolates of MRSA, recovered from December 2010 to May 2014 in a mother and child hospital, CHU Mohamed VI in Marrakech, Morocco, were screened for the presence of bap and ica genes associated with biofilm formation, and for bbp, cna, ebpS, eno, fib, fnbA, fnbB, clfA, and clfB genes that encode microbial surface components recognizing adhesive matrix molecules (MSCRAMMs). The biofilm formation assay was performed in 96-well microtiter polystyrene plates. The presence of genes was determined by polymerase chain reaction (PCR). Results: An association was found between icaD gene detection and biofilm formation; 100% of the strains harbored icaD and produced biofilm. None of the isolates harbored bap or bbp. Furthermore, 96.23% isolates were positive for fnbA, 60.37% for eno, 43.39% for clfA and clfB, 11.32% for cna, 9.34% for ebpS, 5.66% for fib, and 1.89% for fnbA. Conclusions: Our findings showed that the MRSA carriage in Marrakech children was high. The genetic variations of adhesion genes require further investigation.

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Gurfil, P. "Non-linear missile guidance synthesis using control Lyapunov functions." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 219, no. 2 (February 1, 2005): 77–87. http://dx.doi.org/10.1243/095441005x9085.

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This paper derives a new non-linear guidance law aimed at interception of highly manoeuvring targets. The guidance law is developed based on the theory of control Lyapunov functions (CLFs), a methodology for universal stabilization of non-linear systems which is also inverse optimal with respect to some performance measure. The three-dimensional guidance dynamics are formulated in a fixed-line-of-sight coordinate system, yielding matching between the target and missile accelerations. Closed-form expressions for the CLF guidance commands are given. Simulation shows that the new guidance scheme significantly outperforms augmented proportional navigation in short-range engagements.

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Tsompanidou, Eleni, Emma L. Denham, Mark J. J. B. Sibbald, Xiao-mei Yang, Jolien Seinen, Alexander W. Friedrich, Girbe Buist, and Jan Maarten van Dijl. "The Sortase A Substrates FnbpA, FnbpB, ClfA and ClfB Antagonize Colony Spreading of Staphylococcus aureus." PLoS ONE 7, no. 9 (September 7, 2012): e44646. http://dx.doi.org/10.1371/journal.pone.0044646.

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Abd Zaid, A. M., and N. J. Kandala. "RAPID DISCRIMINATION AMONG METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS ISOLATES USING VARIABLE NUMBER TANDEM REPEAT ANALYSIS IN A SAMPLE OF IRAQI PATIENTS AND." IRAQI JOURNAL OF AGRICULTURAL SCIENCES 52, no. 5 (October 21, 2021): 1185–93. http://dx.doi.org/10.36103/ijas.v52i5.1456.

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There is so little information available in Iraq about genetic variability in methicillin resistant Staphylococcus aureus (MRSA), so current study aimed to use six tandem repeat loci of multilocus variable number tandem repeat (MLVA) typing to discriminate among MRSA, so to achieve the aim of this study, six loci, clfA, clfB, sdrC, spa, sspa and sav1078 were selected for multiplex PCR. The PCR product were subjected to capillary electrophoresis by using ABI-Genetic analyzer, then the data were analyzed by using GeneMapper™ Software 5. Fragment sizes were converted into repeats number. The total number of repeats are used to generate allelic profile. The allelic profile used to draw the minimum spanning tree and dendrogram , all the 85 MRSA isolates are clustered into 54 MLVA type.

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Wan, Min-Tao, and Chin-Cheng Chou. "CHARACTERIZATION OF BACTERIAL ADHESION AND BIOFILM FORMATION ABILITY OF LIVESTOCK-ASSOCIATED METHICILLIN-RESISTANTSTAPHYLOCOCCUS AUREUSISOLATED FROM SWINE AND SLAUGHTERHOUSE WASTEWATERS." Taiwan Veterinary Journal 40, no. 02 (June 2014): 101–7. http://dx.doi.org/10.1142/s1682648514500140.

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Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) ST9 has emerged as a potential zoonotic pathogen for humans and animals. Bacterial adhesion factors and biofilms mediate host colonization and infection of MRSA. This study investigated the dynamics of microbial surface components recognizing adhesive matrix molecules (MSCRAMMs), biofilm formation gene (intercellular adhesion [ica]), and biofilm expression in MRSA from the nasal samples of asymptomatic pigs (the nasal group, n = 147) and swine slaughterhouse wastewater samples (the environmental group, n = 86). Biofilm formation was quantified by microtiter plate assay. The most prevalent MSCRAMM profile was clfA-clfB-spa-eno-ebps-fib and more than 70% of the LA-MRSA ST9 isolates harbored the biofilm formation gene. Environmental MRSA harbored lower levels of the ica locus and MSCRAMMs (clfA and fib) than did the nasal group, suggesting possible gene loss. Biofilm production in the nasal group was higher than in the environmental group, indicating the difference in biofilm formation in MRSA isolates from different ecological niches. The higher prevalence of MSCRAMMs, biofilm formation gene, and biofilm production in LA-MRSA ST9 may enhance the persistence and infectivity of MRSA in the swine population and present a threat to the health of livestock as well as farm workers.

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Atanov, N., V. Baranov, L. Borrel, C. Bloise, J. Budagov, S. Ceravolo, F. Cervelli, et al. "Development and construction status of the Mu2e electromagnetic calorimeter mechanical structures." Journal of Instrumentation 17, no. 10 (October 27, 2022): C10021. http://dx.doi.org/10.1088/1748-0221/17/10/c10021.

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Abstract The Mu2e experiment at Fermilab will search for the CLFV neutrino-less coherent conversion of a muon into an electron in the field of an aluminum nucleus. The observation of this process would be the evidence of physics beyond the Standard Model. Mu2e comprises a straw-tracker, an electromagnetic calorimeter and an external veto for cosmic rays. The calorimeter provides electron identification, a fast trigger and aids track reconstruction. It is a state-of-the-art crystal calorimeter and employs 1340 pure CsI crystals readout by UV-extended SiPM and fast electronics. The design consists of two identical annular disks positioned at the relative distance of 70 cm downstream the target.The hostile Mu2e conditions (total ionizing dose of 12 krad and a neutron fluence of 5 × 1010 n/cm2 @ 1 MeVeq (Si)/y, 1 T magnetic field and vacuum level of 10−4 Torr) posed tight constraints on the mechanical structures and materials choice. The support structure of the two crystal matrices employs two aluminum hollow rings and parts made of open-cell vacuum-compatible carbon fiber. SiPMs and front-end electronics for each crystal are assembled in one mechanical unit inserted in a machined copper holder. The units are supported by a plate made of vacuum-compatible material. The plate integrates the cooling system made of a network of copper lines flowing a low temperature fluid and placed in thermal contact with the copper holders. The DAQ is hosted in aluminum crates positioned on the lateral surface of the disks. The crates also integrate the DAQ electronics cooling system. We review the constraints on the calorimeter structures design, the development of all the structural components, including the simulations that have determined the materials and technological choices and the specifications of the cooling station, components production and quality assurance tests, the procedures for detector assembly, transportation and installation in the experimental area.

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Chen, Lin, Zi-Yun Tang, Shi-Yun Cui, Zhen-Bao Ma, Hua Deng, Wei-Li Kong, Li-Wen Yang, Chao Lin, Wen-Guang Xiong, and Zhen-Ling Zeng. "Biofilm Production Ability, Virulence and Antimicrobial Resistance Genes in Staphylococcus aureus from Various Veterinary Hospitals." Pathogens 9, no. 4 (April 4, 2020): 264. http://dx.doi.org/10.3390/pathogens9040264.

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Staphylococcus aureus (S. aureus) is one of the most clinically important zoonotic pathogens, but an understanding of the prevalence, biofilm formulation ability, virulence, and antimicrobial resistance genes of S. aureus from veterinary hospitals is lacking. By characterizing S. aureus in different origins of veterinary hospitals in Guangzhou, China, in 2019, we identified with the presence of S. aureus in pets (17.1%), veterinarians (31.7%), airborne dust (19.1%), environmental surfaces (4.3%), and medical device surfaces (10.8%). Multilocus sequence typing (MLST) and Staphylococcus protein A (spa) typing analyses demonstrated methicillin-sensitive S. aureus (MSSA) ST398-t571, MSSA ST188-t189, and methicillin-resistant S. aureus (MRSA) ST59-t437 were the most prevalent lineage. S. aureus with similar pulsed-field gel electrophoresis (PFGE) types distributed widely in different kinds of samples. The crystal violet straining assays revealed 100% (3/3) of MRSA ST59 and 81.8% (9/11) of MSSA ST188 showed strong biofilm formulation ability, whereas other STs (ST1, ST5, ST7, ST15, ST88, ST398, ST3154 and ST5353) showed weak biofilm production ability. Polymerase chain reaction (PCR) confirmed the most prevalent leucocidin, staphylococcal enterotoxins, ica operon, and adhesion genes were lukD-lukE (49.0%), sec-sel (15.7%), icaA-icaB-icaC-icaR (100.0%), and fnbB-cidA-fib-ebps-eno (100.0%), respectively. Our study showed that the isolates with strong biofilm production ability had a higher prevalence in clfA, clfB, fnbA and sdrC genes compared to the isolates with weak biofilm production ability. Furthermore, 2 ST1-MRSA isolates with tst gene and 1 ST88-MSSA isolate with lukS/F-PV gene were detected. In conclusion, the clonal dissemination of S. aureus of different origins in veterinary hospitals may have occurred; the biofilm production capacity of S. aureus is strongly correlated with ST types; some adhesion genes such as clfA, clfB, fnbA, and sdrC may pose an influence on biofilm production ability and the emergence of lukS/F-PV and tst genes in S. aureus from veterinary hospitals should raise our vigilance.

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Atshan, Salman Sahab, Rukman Awang Hamat, Marco J. L. Coolen, Gary Dykes, Zamberi Sekawi, Benjamin J. Mullins, Leslie Thian Lung Than, Salwa A. Abduljaleel, and Anthony Kicic. "The Role of Subinhibitory Concentrations of Daptomycin and Tigecycline in Modulating Virulence in Staphylococcus aureus." Antibiotics 10, no. 1 (January 3, 2021): 39. http://dx.doi.org/10.3390/antibiotics10010039.

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Staphylococcus aureus (S. aureus) infections are notoriously complicated by the ability of the organism to grow in biofilms and are difficult to eradicate with antimicrobial therapy. The purpose of the current study was to clarify the influence of sub-inhibitory concentrations (sub-MICs) of daptomycin and tigecycline antibiotics on biofilm adhesion factors and exoproteins expressions by S. aureus clinical isolates. Six clinical isolates representing positive biofilm S. aureus clones (3 methicillin-sensitive S. aureus (MSSA) and 3 methicillin-resistant S. aureus (MRSA)) were grown with sub-MICs (0.5 MIC) of two antibiotics (daptomycin and tigecycline) for 12 h of incubation. RNA extracted from culture pellets was used via relative quantitative real-time-PCR (qRT-PCR) to determine expression of specific adhesion (fnbA, fnbB, clfA, clfB, fib, ebps, cna, eno) and biofilm (icaADBC) genes. To examine the effect of sub-MIC of these antibiotics on the expression of extracellular proteins, samples from the culture supernatants of six isolates were collected after 12 h of treatment with or without tigecycline in order to profile protein production via 2D gel sodium dodecyl sulfate-polyacrylamide gel electrophoresis (2D gel-SDS-PAGE). Sub-MIC treatment of all clinical MRSA and MSSA strains with daptomycin or tigecycline dramatically induced or suppressed fnbA, fnbB, clfA, clfB, fib, ebps, cna, eno, and icaADBC gene expression. Furthermore, sub-MIC use of tigecycline significantly reduced the total number of separated protein spots across all the isolates, as well as decreasing production of certain individual proteins. Collectively, this study showed very different responses in terms of both gene expression and protein secretion across the various isolates. In addition, our results suggest that sub-MIC usage of daptomycin and tigecycline could signal virulence induction by S. aureus via the regulation of biofilm adhesion factor genes and exoproteins. If translating findings to the clinical treatment of S. aureus, the therapeutic regimen should be adapted depending on antibiotic, the virulence factor and strain type.

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Fronzoni, G., M. Stener, and P. Decleva. "Theoretical description of the NEXAFS Cl 1s and 2p spectra of ClF and ClF3." Chemical Physics 246, no. 1-3 (July 1999): 127–45. http://dx.doi.org/10.1016/s0301-0104(99)00124-x.

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40

Gladys Pinilla, Gladys, Angela Bautista, Claudia Cruz, Bibiana Chavarro, Jeannette Navarrete, Liliana Muñoz, and Jennifer Gutiérrez. "Determinación de factores de adhesión asociados a la formación de biopelícula en aislamientos clínicos de Staphylococcus aureus y Staphylococcus epidermidis." Nova 15, no. 27 (August 10, 2017): 67. http://dx.doi.org/10.22490/24629448.1959.

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<p>Los factores de adhesión son determinantes de virulencia que se expresan en microorganismos que tienen la capacidad de formar biopelícula, contribuyendo a la gravedad de infecciones intrahospitalarias. Dentro de estos componentes de la superficie microbiana que reconocen moléculas de adhesión de matriz conocidas como MSCRAMMs, se incluyen el factor de unión a fibronectina A y B, (FnbA y B) factor de aglutinación A y B (ClfA y B) y factor de unión a fibrinógeno (Fib), que se han descrito en Staphylococcus aureus y reaccionan con proteínas de la matriz extracelular humana. El objetivo de este estudio fue determinar la presencia de estos factores de adhesión relacionados con la formación de biopelicula en Staphylococcus. Método. Se caracterizaron fenotípica y genotípicamente 30 aislamientos clínicos de Staphylococcus aureus y Staphylococcus epidermidis, provenientes de pacientes inmunocomprometidos en tres instituciones hospitalarias de Bogotá. La producción de Biopelícula se determinó mediante Rojo Congo y Cristal violeta y mediante PCR convencional y múltiplex se amplificaron los genes FnbA y B, ClfA y B y Fib, así como los genes del operón ica ADBC. Resultados. Todos los aislamientos clínicos fueron positivos genotípica y fenotípicamente para la producción de Biopelícula, encontrándose<br />la presencia del operón completo en el 88.9%, los factores ClfA y ClfB en un 70%; Fib en un 60%, FnbB en un 23% y FnbA en el 17%. Conclusiónes. En este estudio se evidenció la presencia de estos factores de virulencia en S. pidermidis, los cuáles hasta el momento se han reportado únicamente en S.aureus. Este hallazgo es importante ya que se sugiere la relación con transferencia horizontal de genes entre estas especies, siendo el S. epidermidis un importante reservorio genético, y un importante patobionte causal de infecciones nosocomiales, asociado con dispositivos médicos.</p>

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Kim, Hyoung-Geun, Young Sung Jung, Seon Min Oh, Hyun-Ji Oh, Jung-Hwan Ko, Dae-Ok Kim, Se Chan Kang, Yeong-Geun Lee, Dae Young Lee, and Nam-In Baek. "Coreolanceolins A–E, New Flavanones from the Flowers of Coreopsis lanceolate, and Their Antioxidant and Anti-Inflammatory Effects." Antioxidants 9, no. 6 (June 19, 2020): 539. http://dx.doi.org/10.3390/antiox9060539.

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(1) Background: Many flavonoids derived from natural sources have been reported to exhibit antioxidant and anti-inflammatory effects. Our preliminary study suggested that Coreopsis lanceolata flowers (CLFs) include high flavonoid content; (2) Methods: CLFs were extracted in 80% (v/v) aqueous methanol and fractionated into ethyl acetate, n-butanol, and water fractions. Repeated column chromatographies for the organic fractions led to the isolation of seven flavanones. Quantitative analysis of the flavanones was carried out using reversed-phase high-performance liquid chromatography. All flavanones were evaluated for their antioxidant and pro-inflammatory inhibition effects; (3) Results: Spectroscopic analyses revealed the chemical structure of five new flavanones, coreolanceolins A–E, and two known ones. The content of the seven flavanones in extracts were determined from 0.8 ± 0.1 to 38.8 ± 0.3 mg/g. All flavanones showed radical scavenging activities (respectively 104.3 ± 1.9 to 20.5 ± 0.3 mg vitamin C equivalents (VCE)/100 mg and 1278.6 ± 26.8 to 325.6 ± 0.2 mg VCE/100 mg) in the DPPH and 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays and recovery activities in Caco-2 (59.7 to 41.1%), RAW264.7 (87.8 to 56.0%), and PC-12 (100.5 to 69.9%) cells against reactive oxygen species. Furthermore, all flavanones suppressed nitric oxide production (99.5% to 37.3%) and reduced iNOS and COX-2 expression in lipopolysaccharide-treated RAW 264.7 cells; (4) Conclusions: Five new and two known flavanones were isolated from CLF, and most of them showed high antioxidant and pro-inflammatory inhibition effects.

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Mace, B. R., and L. Ji. "The statistical energy analysis of coupled sets of oscillators." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 463, no. 2081 (March 6, 2007): 1359–77. http://dx.doi.org/10.1098/rspa.2007.1824.

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The paper concerns the statistical energy analysis (SEA) of two conservatively coupled oscillators, sets of oscillators and continuous subsystems under broadband excitation. The oscillator properties are assumed to be random and ensemble averages found. Account is taken of the correlation between the coupling parameters and the oscillator energies. For coupled sets of oscillators or continuous subsystems, it is assumed that the coupling power between a pair of oscillators is proportional to the difference of either their actual energies or their ‘blocked’ energies, and expressions for the ensemble averages and coupling loss factors (CLFs) are found. Various observations are made, some of which differ from those that are commonly assumed within SEA. The coupling power and CLF are governed by two parameters: the ‘strength of connection’ and the ‘strength of coupling’. The CLF is proportional to damping at low damping and independent of damping in the high damping, weak coupling limit. Equipartition of energy does not occur as damping tends to zero, except for the case of two oscillators that have identical natural frequencies. While attention is focused on spring-coupled oscillators, similar results hold for more general forms of conservative coupling. The examples of two spring-coupled rods and two spring-coupled plates are considered. Conventional SEA and the coupled oscillator results are in good agreement for weak coupling but diverge for strong coupling. For strong coupling and weak connection, the coupled oscillator results agree well with an exact wave analysis and Monte Carlo simulations.

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Acosta, Atzel C., Pollyanne Raysa F. Oliveira, Laís Albuquerque, Isamara F. Silva, Elizabeth S. Medeiros, Mateus M. Costa, José Wilton Pinheiro Junior, and Rinaldo A. Mota. "Frequency of Staphylococcus aureus virulence genes in milk of cows and goats with mastitis." Pesquisa Veterinária Brasileira 38, no. 11 (November 2018): 2029–36. http://dx.doi.org/10.1590/1678-5150-pvb-5786.

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ABSTRACT: The present study determined the frequency of Staphylococcus aureus virulence genes in 2,253 milk samples of cows (n=1000) and goats (n=1253) raised in three different geographical regions of the state Pernambuco, Brazil. The presence of genes of virulence factors associated to adhesion to host cells (fnbA, fnbB, clfA and clfB), toxinosis (sea, seb, sec, sed, seg, seh, sei, tsst, hla and hlb), and capsular polysaccharide (cap5 and cap8) was evaluated by PCR. A total of 123 and 27 S. aureus strains were isolated from cows’ and goats’ milk, respectively. The sec and tsst genes were detected exclusively in goats’ isolates, while the seh gene was only identified in cows’ isolates. The number of toxin genes per strain showed that goats’ isolates are likely more toxic than bovines’ isolates. The cap5 genotype predominated in both host species, especially in strains collected from cows raised in the Agreste region. The cap8 genotype is likely more virulent due to the number of virulence genes per strain. The results of the present study demonstrate that S. aureus may pose a potential threat to human health in Brazil, and, therefore, these results should support actions related to mastitis control programs.

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Bhowmick, Aklant K., Tiziana DiMatteo, Sarah Eftekharzadeh, and Adam D. Myers. "On the small-scale clustering of quasars: constraints from the MassiveBlack II simulation." Monthly Notices of the Royal Astronomical Society 485, no. 2 (February 20, 2019): 2026–40. http://dx.doi.org/10.1093/mnras/stz519.

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Abstract We examine recent high-precision measurements of small-scale quasar clustering (at z ∼ 0.5–2 on scales of ${\sim }25~\mathrm{kpc}\, h^{-1}$) from the SDSS in the context of the MassiveBlack II (MBII) cosmological hydrodynamic simulation and conditional luminosity function (CLF) modelling. At these high luminosities (g < 20.85 quasars), the MBII simulation volume ($100~\mathrm{cMpc}\, h^{-1}$ comoving boxsize) has only three quasar pairs at distances of 1–4 Mpc. The black hole masses for the pairs range between $M_{\rm bh}\sim 1{\, \rm and\, }3\times 10^{9}~\mathrm{M}_{\odot }\, h^{-1}$ and the quasar hosts are haloes of $M_{\rm h}\sim 1\hbox{--}3\times 10^{14}~\mathrm{M}_{\odot }\, h^{-1}$. Such pairs show signs of recent major mergers in the MBII simulation. By modelling the central and satellite AGN CLFs as lognormal and Schechter distributions, respectively (as seen in MBII AGNs), we arrive at CLF models which fit the simulation predictions and observed luminosity function and the small-scale clustering measured for the SDSS sample. The small-scale clustering of our mock quasars is well-explained by central--satellite quasar pairs that reside in $M_{\rm h}\gt 10^{14}~\mathrm{M}_{\odot }\, h^{-1}$ dark matter haloes. For these pairs, satellite quasar luminosity is similar to that of central quasars. Our CLF models imply a relatively steep increase in the maximum satellite luminosity, $L^*_{\mathrm{sat}}$, in haloes of $M_{\rm h}\gt 10^{14}~\mathrm{M}_{\odot }\, h^{-1}$ with associated larger values of $L^*_{\mathrm{sat}}$ at higher redshift. This leads to increase in the satellite fraction that manifests itself in an enhanced clustering signal at ≲1 Mpc h−1. For the ongoing eBOSS-CORE sample, we predict ∼200–500 quasar pairs at z ∼ 1.5 (with $M_{\rm h} \gtrsim 10^{13}~\mathrm{M}_{\odot }\, h^{-1}$ and $M_{\rm bh} \gtrsim 10^{8}~\mathrm{M}_{\odot }\, h^{-1}$) at ∼25 kpc scales. Such a sample would be ≳ 10 times larger than current pair samples.

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Kim, Wook-Hee, Jihye Seo, Jinwoong Kim, and Beomseok Nam. "clfB-tree." ACM Transactions on Storage 14, no. 1 (April 4, 2018): 1–17. http://dx.doi.org/10.1145/3129263.

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Hair, Pamela S., Charlene G. Echague, Amber M. Sholl, Justin A. Watkins, Joan A. Geoghegan, Timothy J. Foster, and Kenji M. Cunnion. "Clumping Factor A Interaction with Complement Factor I Increases C3b Cleavage on the Bacterial Surface of Staphylococcus aureus and Decreases Complement-Mediated Phagocytosis." Infection and Immunity 78, no. 4 (January 25, 2010): 1717–27. http://dx.doi.org/10.1128/iai.01065-09.

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ABSTRACT The human complement system is important in the immunological control of Staphylococcus aureus infection. We showed previously that S. aureus surface protein clumping factor A (ClfA), when expressed in recombinant form, bound complement control protein factor I and increased factor I cleavage of C3b to iC3b. In the present study, we show that, compared to the results for the wild type, when isogenic ClfA-deficient S. aureus mutants were incubated in serum, they bound less factor I, generated less iC3b on the bacterial surface, and bound fewer C3 fragments. It has been shown previously that two amino acids in ClfA (P336 and Y338) are essential for fibrinogen binding. However, S. aureus expressing ClfA(P336A Y338S) was less virulent than ClfA-deficient strains in animal models. This suggested that ClfA contributed to S. aureus virulence by a mechanism different than fibrinogen binding. In the present study, we showed that S. aureus expressing ClfA(P336A Y338S) was more susceptible to complement-mediated phagocytosis than a ClfA-null mutant or the wild type. Unlike ClfA, ClfA(P336A Y338S) did not enhance factor I cleavage of C3b to iC3b and inhibited the cofactor function of factor H. Fibrinogen enhanced factor I binding to ClfA and the S. aureus surface. Twenty clinical S. aureus strains all expressed ClfA and bound factor I. High levels of factor I binding by clinical strains correlated with poor phagocytosis. In summary, our results suggest that the interaction of ClfA with factor I contributes to S. aureus virulence by a complement-mediated mechanism.

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Xu, Haiyang, Changmin Hu, Rui Gong, Yingyu Chen, Ningning Ren, Ganwen Xiao, Qian Xie, et al. "Evaluation of a Novel Chimeric B Cell Epitope-Based Vaccine against Mastitis Induced by Either Streptococcus agalactiae or Staphylococcus aureus in Mice." Clinical and Vaccine Immunology 18, no. 6 (April 20, 2011): 893–900. http://dx.doi.org/10.1128/cvi.00066-11.

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ABSTRACTTo construct a universal vaccine against mastitis induced by eitherStreptococcus agalactiaeorStaphylococcus aureus, the B cell epitopes of the surface immunogenic protein (Sip) fromS. agalactiaeand clumping factor A (ClfA) fromS. aureuswere analyzed and predicted.sip-clfA, a novel chimeric B cell epitope-based gene, was obtained by overlap PCR, and then the recombinant Sip-ClfA (rSip-ClfA) was expressed and purified. rSip-ClfA and inactivatedS. agalactiaeandS. aureuswere formulated into different vaccines with mineral oil as the adjuvant and evaluated in mouse models. The rSip-ClfA vaccination induced immunoglobulin G (IgG) titers higher than those seen in groups immunized with inactivated bacteria. Furthermore, the response to rSip-ClfA immunization was characterized as having a dominant IgG1 subtype, whereas both bacterial immunizations produced similar levels of IgG1 and IgG2a. The antiserum capacities for opsonizing adhesion and phagocytosis were significantly greater in the rSip-ClfA immunization group than in the killed-bacterium immunization groups (P< 0.05). The immunized lactating mice were challenged with eitherS. agalactiaeorS. aureusvia the intramammary route. At 24 h postinfection, the numbers of bacteria recovered from the mammary glands in the rSip-ClfA group were >5-fold lower than those in both inactivated-bacterium groups (P< 0.01). Histopathological examination of the mammary glands showed that rSip-ClfA immunization provided better protection of mammary gland tissue integrity against bothS. agalactiaeandS. aureuschallenges. Thus, the recombinant protein rSip-ClfA would be a promising vaccine candidate against mastitis induced by eitherS. agalactiaeorS. aureus.

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Wolz, Christiane, Christiane Goerke, Regine Landmann, Werner Zimmerli, and Ursula Fluckiger. "Transcription of Clumping Factor A in Attached and Unattached Staphylococcus aureus In Vitro and during Device-Related Infection." Infection and Immunity 70, no. 6 (June 2002): 2758–62. http://dx.doi.org/10.1128/iai.70.6.2758-2762.2002.

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ABSTRACT Staphylococcus aureus is one of the pathogens most frequently isolated in device-related infections. S. aureus is equipped with surface-associated proteins promoting specific binding to matrix molecules. Clumping factor A (ClfA, encoded by clfA) mediates adhesion to fibrinogen. Whereas the contribution of ClfA to pathogenicity is well documented, the influence of different growth and host parameters on gene activity is unclear. To elucidate this question, we investigated clfA transcript levels in an animal model of device-related infection and in planktonic and sessile bacteria grown in vitro. Specific mRNA from the S. aureus strains Newman, Reynolds, and RN6390 was quantified by LightCycler reverse transcription-PCR. In vitro, clfA transcript levels were low in the early logarithmic growth phase, but a clear increase was observed after the late logarithmic phase. Quantities of clfA transcripts were four to six times higher in the planktonic than in the sessile bacterial subpopulations grown to the stationary phase. During infection, in strains Newman and Reynolds levels of clfA transcripts in exudates accumulating in the infected devices were lower than those in the bacteria grown in vitro to stationary phase. clfA mRNA levels in the exudates increased during the initial phase of infection and remained constant after 96 h postinoculation. In contrast to the in vitro results, quantities of clfA transcripts in the unattached bacteria of the exudates never exceeded the level of clfA transcripts in the sessile bacteria attached to glass beads. However, a clear increase in clfA quantities in the sessile bacteria was observed late in infection after 144 h. In conclusion, maximal clfA transcript levels are reached late during growth in vitro and in vivo.

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Jung, Hye-Ri, and Young Ju Lee. "Characterization of Virulence Factors in Enterotoxin-Producing Staphylococcus aureus from Bulk Tank Milk." Animals 12, no. 3 (January 26, 2022): 301. http://dx.doi.org/10.3390/ani12030301.

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Staphylococcus aureus, a persistent mastitis-causing pathogen, produces various virulence factors, including enterotoxins. This study analyzed the genetic characteristics of bovine-mastitis-related virulence factors to evaluate the potential pathogenesis of S. aureus isolated from bulk tank milk. Among 93 S. aureus isolates from 396 dairy farms operated by 3 dairy companies in Korea, 40 (43.0%) isolates carried one or more enterotoxin genes. Moreover, S. aureus carrying enterotoxin genes showed a higher prevalence in all virulence genes tested in this study except for pvl and lukM, which were not detected in any isolate, than in the isolates without enterotoxin genes. In particular, the prevalence of six genes (hla, hlb, lukED, fnbA, clfA, and clfB) was significantly higher in S. aureus carrying the enterotoxin genes than in the isolates without the enterotoxin genes (p < 0.05). The most common multilocus sequence type of enterotoxin-producing isolates was ST188, and all isolates of ST188 harbored the see gene. S. aureus isolated from bulk tank milk, not from mastitis, had a high prevalence of virulence factors, posing a public health threat. Moreover, a high presence of enterotoxins in bulk tank milk is probably because of poor hygiene; therefore, it is important to develop strong monitoring and sanitation programs for dairy factories.

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Rodríguez-Acosta, Fátima, Silvina Fernández, Sol Haim, Marta Mollerach, Wilma Basualdo, Héctor Castro, Beatriz Quiñónez †, and Rosa María Guillén-Fretes. "Estandarización del análisis multi-locus de número variable de repeticiones en tándem para el estudio de Staphylococcus aureus resistentes a meticilina aislados de la comunidad en Paraguay." Duazary 14, no. 2 (July 1, 2017): 131. http://dx.doi.org/10.21676/2389783x.1971.

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Staphylococcus aureus es un patógeno capaz de causar infecciones con amplio rango de severidad y adaptarse a diferentes tejidos. Su epidemiología es compleja, por circulación de cientos de clones a nivel mundial, lo que requiere de métodos moleculares reproducibles y de alto poder discriminatorio para la identificación de los mismos. El presente estudio tuvo como objetivo principal la estandarización del análisis multi-locus de número variable de repeticiones en tándem (MLVA) para análisis de variabilidad genética de aislados de S. aureus previamente tipificados por electroforesis en gel de campo pulsado (PFGE), gold standard para tipificación de aislados. La MLVA se realizó por amplificación de 7 locus VNTR (clfA, clfB, sdrC, sdrD, sdrE, sspA y spA) por PCR. Se alcanzó un alto nivel de reproducibilidad. El empleo de cepas previamente tipificadas por análisis de secuencias multi-locus (MLST), PFGE, locus spa y cassette SCCmec, permitió validar de forma comparativa el agrupamiento generado por MLVA. Los aislados que fueron agrupados como idénticos por MLVA presentaron resultados congruentes con la totalidad de las otras técnicas moleculares y ésta demostró ser más sensible que PFGE para distinguir entre aislados que presentaron patrones PFGE idénticos. La MLVA cumple todos los criterios de un método de tipificación útil.

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Journal articles on the topic 'CLFV'

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