27,645 research outputs found
Understanding Factors in Group B Streptococcus Late-Onset Disease
No full textAlberto Berardi,1 Viola Trevisani,2 Antonella Di Caprio,2 Jenny Bua,3 Mariachiara China,4 Barbara Perrone,5 Rossella Pagano,6 Laura Lucaccioni,7 Silvia Fanaro,8 Lorenzo Iughetti,2,7 Licia Lugli,1 Roberta Creti9 1Terapia Intensiva Neonatale, Azienda Ospedaliero-Universitaria Policlinico, Modena, Italy; 2Scuola di Specializzazione in Pediatria, Università di Modena & Reggio Emilia, Modena, Italy; 3Terapia Intensiva Neonatale, IRCCS Azienda Ospedaliero Universitaria “Burlo Garofalo”, Trieste, Italy; 4Terapia Intensiva Neonatale, Ospedale Infermi, Rimini, Italy; 5Terapia Intensiva Neonatale, Azienda Ospedaliero Universitaria Ospedali Riuniti, Ancona, Italy; 6Unità Operativa di Pediatria, Civile Sassuolo, Sassuolo, Italy; 7Unità Operativa di Pediatria, Azienda Ospedaliero-Universitaria Policlinico, Modena, Italy; 8Terapia Intensiva Neonatale, Azienda Ospedaliero-Universitaria S. Anna, Ferrara, Italy; 9Reparto di Antibiotico Resistenza e Patogeni Speciali (AR-PS), Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, ItalyCorrespondence: Alberto Berardi Tel +39 059 4222522Fax +39 059 42223770Email [email protected]: Group B streptococcus (GBS) infection remains a leading cause of sepsis, pneumonia, and meningitis in infants. Rates of GBS early onset disease have declined following the widcespread use of intrapartum antibiotic prophylaxis; hence, late-onset infections (LOGBS) are currently a common presentation of neonatal GBS dicsease. The pathogenesis, mode of transmission, and risk factors associated with LOGBS are unclear, which interfere with effective prevention efforts. GBS may be transmitted from the mother to the infant at the time of delivery or during the postpartum period via contaminated breast milk, or as nosocomial or community-acquired infection. Maternal GBS colonization, prematurity, young maternal age, HIV exposure, and ethnicity (Black) are identified as risk factors for LOGBS disease; however, further studies are necessary to confirm additional risk factors, if any, for the implementation of effective prevention strategies. This narrative review discusses current and previous studies that have reported LOGBS. Few well-designed studies have described this condition; therefore, reliable assessment of maternal GBS colonization, breastfeeding, and twin delivery as risk factors for LOGBS remains limited.Keywords: neonatal sepsis, prevention, infant, meningitis, CC1
VUV resonance radiation trapping in an effusive He beam
No full textWe have characterized experimentally the trapping of resonance radiation in an effusive He beam produced by a needle injector. In order to take into account the influence of secondary effects, such as collisions, on the trapping process, the measurements were carried out by investigating the line intensity dependence on the atomic density of transitions 3(1)P --> 2(1)S (lambda = 501.6 nm), and 3(1)D --> 2(1)P (lambda = 667.8 nm) in the visible and 3(1)P --> 1(1)S (lambda = 53.7 nm) and 2(1)P --> 1(1)S (lambda = 58.4 nm) in the vacuum ultraviolet region of the helium spectrum. The comparison between visible and vacuum ultraviolet spectra allowed us to characterize the excitation process and to evaluate the contribution of collisional effects. We have calculated the escape factor, g, as a function of the atomic density and of the distance from the needle injector, i.e. along the beam path. The results were also compared with the Holstein and Phelps approach describing the trapping process in terms of an effective radius, rho. Our results show that in the case of an effusive beam, the effective radius is of the order of the effusive beam radius, namely rho(b) = 0.70 +/- 0.04 mm. RI Berardi, Vincenzo/H-4550-201
Improvement of ferrocene acylation. Conventional vs. microwave heating for scandium-catalyzed reaction in alkylmethylimidazolium-based ionic liquids
No full textAcylation of ferrocene-catalyzed by scandium triflate was thoroughly investigated. Reaction time and temperature are important parameters, in that prolonged treatment causes substrate decomposition and/or catalyst deactivation. Hydrophobic alkylmethylimidazolium-based solvents gave best results, in particular 1-butyl-3-methylimidazolium bis(trifluorometansulfonyl) imide. Anhydrides behave as superior acylating reagents with respect to acyl chlorides. MW irradiation allowed to quantitatively acylate ferrocene within minutes. (C) 2008 Elsevier B. V. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Measurement of the ratio of branching fractions B(B0→K∗0γ )/B(B0s→φγ ) and the directCP asymmetry inB 0→K∗0γ
No full textThe ratio of branching fractions of the radiative B decays B0→K⁎0γ and B0s→ϕγ has been measured using an integrated luminosity of 1.0 fb−1 of pp collision data collected by the LHCb experiment at a centre-of-mass energy of s√=7TeV. The value obtained is
B(B0→K⁎0γ)B(B0s→ϕγ)=1.23±0.06(stat.)±0.04(syst.)±0.10(fs/fd),
where the first uncertainty is statistical, the second is the experimental systematic uncertainty and the third is associated with the ratio of fragmentation fractions fs/fd. Using the world average value for B(B0→K⁎0γ), the branching fraction B(B0s→ϕγ) is measured to be (3.5±0.4)×10−5.
The direct CP asymmetry in B0→K⁎0γ decays has also been measured with the same data and found to be
ACP(B0→K⁎0γ)=(0.8±1.7(stat.)±0.9(syst.))%.
Both measurements are the most precise to date and are in agreement with the previous experimental results and theoretical expectations
ROLE OF PHYSICAL ACTIVITY AND OXIDATIVE STRESS IN CACHEXIA
No full textCachexia is a muscle wasting syndrome leading to muscle atrophy and weakness associated to most chronic diseases, including cancer, acquired immune deficiency syndrome,
rheumatoid arthritis, chronic obstructive pulmonary disease,
renal failure. Cachexia is a critical issue in the comprehensive
approach to chronic patients since it affects morbidity, mortality and quality of life. Physical exercise has important effects on secondary prevention or intervention against several diseases. Although there are good reasons to recommend regular physical activity in patient populations, recommending exercise is not a straightforward endeavor in patients with chronic diseases. Oxidative stress may be a pivotal etiological factor in the onset of cachexia. Expression of muscle specific ubiquitin ligase responsible for muscle wasting is increased by oxidative stress, whereas nitric oxide may protect against muscle atrophy. Also, endurance exercise causes oxidative stress. Thus the question arises
whether to exercise or not to exercise in cachexia
Experimental analysis on the time-dependent bonding of FRP laminates under sustained loads
No full textFiber reinforced composite materials are frequently used in the rehabilitation or upgrading of existing structures. From a design point of view, current international guidelines on FRP strengthening applications do not give rules based on rigorous approaches to evaluate the reliability and durability of strengthening interventions with respect to long-term behavior. In order to give a contribution on this topic, the authors have carried out a creep experimental program on retrofitting systems, either of carbon or glass fibers and subject to different stress values in regime of constant temperature. The tests have been carried out by means of a dedicated test device that provided a pure bending stress state in the strengthened beam, being the external loads held constant over time. In this paper the results of their investigation and critical analysis are presented. © 2012 Elsevier Ltd. All rights reserved
Branching fraction and CP asymmetry of the decays B+→K0Sπ+ and B+→K0SK+
No full textAn analysis of B+ → K0
Sπ+ and B+ → K0
S K+ decays is performed with the LHCb experiment. The pp
collision data used correspond to integrated luminosities of 1 fb−1 and 2 fb−1 collected at centre-ofmass
energies of
√
s = 7 TeV and
√
s = 8 TeV, respectively. The ratio of branching fractions and the
direct CP asymmetries are measured to be B(B+ → K0
S K+
)/B(B+ → K0
Sπ+
) = 0.064 ± 0.009 (stat.) ±
0.004 (syst.), ACP(B+ → K0
Sπ+
) = −0.022 ± 0.025 (stat.) ± 0.010 (syst.) and ACP(B+ → K0
S K+
) =
−0.21 ± 0.14 (stat.) ± 0.01 (syst.). The data sample taken at
√
s = 7 TeV is used to search for
B+
c
→ K0
S K+ decays and results in the upper limit ( fc · B(B+
c
→ K0
S K+
))/( fu · B(B+ → K0
Sπ+
)) <
5.8 × 10−2 at 90% confidence level, where fc and fu denote the hadronisation fractions of a ¯b
quark
into a B+
c or a B+ meson, respectively
Perfect octagon quadrangle systems
No full textAn octagon quadrangle is the graph consisting of an 8-cycle (x1,...,x8) with two additional chords: the edges {x1,x4},{x1,x4} and {x5,x8}. An octagon quadrangle system (OQS) of order v and index λ is a pair (X,B), where X is a finite set of v vertices and B is a collection of edge disjoint octagon quadrangles, which partitions the edge set of λK(v) defined on X. An OQS Σ=(X,B) of order v and index λ is strongly perfect if the collection of all the inside 4-cycles contained in the octagon quadrangles form a μ-fold 4-cycle system of order v, and the collection of all the outside 8-cycle quadrangles contained in the octagon quadrangles form a ρ-fold 8-cycle system of order v. More generally, C4-perfect OQSs and C8-perfect OQSs are also defined. In this paper, following the ideas of polygon systems introduced by L. Gionfriddo in her papers [Bull. Inst. Combin. Appl. 48 (2006), 73-81; MR2259705; Discrete Math. 308 (2008), no. 2-3, 231-241; MR2378021 (2008k:05167); Australas. J. Combin. 36 (2006), 167-176; MR2262617 (2007e:05025); Discrete Math. 309 (2009), no. 2, 505-512; MR2478727 (2010f:05122)], we determine completely the spectrum of strongly perfect OQSs, C4-perfect OQSs and C8-perfect OQSs, having the minimum possible value for their indices
Observations of Bºs→ψ(2S)η and Bº(s)→ψ(2S)π+π- decays
No full textFirst observations of the B0s
→ψ(2S)η, B0 →ψ(2S)π
+
π
− and B0s
→ψ(2S)π
+
π
− decays are made
using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in
proton–proton collisions at a centre-of-mass energy of
√
s = 7 TeV. The ratios of the branching fractions
of each of the ψ(2S) modes with respect to the corresponding J/ψ decays are
B(B0s
→ψ(2S)η)
÷
B(B0s
→J/ψη)
= 0.83± 0.14 (stat)±0.12 (syst) ±0.02 (B),
;
B(B0→ψ(2S)π
+
π
−
)
÷
B(B0→J/ψπ
+
π
−
)
= 0.56± 0.07 (stat)±0.05 (syst)± 0.01 (B),
;
B(B0s
→ψ(2S)π
+
π
−
)
÷
B(B0s
→J/ψπ
+
π
−
)
= 0.34± 0.04 (stat)±0.03 (syst)± 0.01 (B),
where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψ
and ψ(2S) meson decays
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