1,058 research outputs found
Silver coordination polymers with tri- and hexacyanoethyl-functionalized macrocyclic ligands
Tri-and hexa-cyanoethyl functionalized 17-(L-1) and 42-membered (L-2) macrocyclic compounds were obtained by [1 + 1] (for L-1) or [2 + 2] (for L-2) cyclocondensation of the corresponding dialdehyde and diethylenetriamine, followed by hydrogenation by KBH4 and subsequent cyano-functionalization with acrylonitrile. They react with silver nitrate, leading to the formation of [AgL1](NO3) (1) and of the metalorganic coordination polymers [Ag-2(NO3)(2)L-1](n) (2) and {[Ag2L2](NO3)(2)}(n) (3). The complexes were characterized by elemental analysis, H-1 NMR, C-13 NMR, IR spectroscopies, and ESI-MS; moreover, L-2, 1, 2 and 3 were also characterized by single crystal X-ray diffraction. The metal cation in 1 is pentacoordinated with a N3O2 coordination environment; in 2, the metal cations display N4O2 octahedral and N2O3 square-pyramid coordination and in 3 they are in square-planar N-4 sites. In 1, the ligand acts as a pentadentate chelator, and in the other two cases, the ligands behave as octadentate chelators in a 1 kappa N-3:kappa O-2,2 kappa N,3 kappa N,4 kappa N (in 2) or 1 kappa N-3,2 kappa N-3,3 kappa N,4 kappa N fashion (in 3). The cyanoethyl strands of the ligands are directly involved in the formation of the 2D frameworks of 2 and 3, which in the former polymer can be viewed as a net composed of hexametallic 36-membered macrocyclic rings and in the latter generates extra hexametallic 58-membered cyclic sets that form zig-zag layers. The thermal analytical and electrochemical properties of these silver complexes were also studied
A20 deficiency causes spontaneous neuroinflammation in mice
Background: A20 (TNFAIP3) is a pleiotropic NFκB-dependent gene that terminates NFκB activation in response to inflammatory stimuli. The potent anti-inflammatory properties of A20 are well characterized in several organs. However, little is known about its role in the brain. In this study, we investigated the brain phenotype of A20 heterozygous (HT) and knockout (KO) mice. Methods: The inflammatory status of A20 wild type (WT), HT and KO brain was determined by immunostaining, quantitative PCR, and Western blot analysis. Cytokines secretion was evaluated by ELISA. Quantitative results were statistically analyzed by ANOVA followed by a post-hoc test. Results: Total loss of A20 caused remarkable reactive microgliosis and astrogliosis, as determined by F4/80 and GFAP immunostaining. Glial activation correlated with significantly higher mRNA and protein levels of the pro-inflammatory molecules TNF, IL-6, and MCP-1 in cerebral cortex and hippocampus of A20 KO, as compared to WT. Basal and TNF/LPS-induced cytokine production was significantly higher in A20 deficient mouse primary astrocytes and in a mouse microglia cell line. Brain endothelium of A20 KO mice demonstrated baseline activation as shown by increased vascular immunostaining for ICAM-1 and VCAM-1, and mRNA levels of E-selectin. In addition, total loss of A20 increased basal brain oxidative/nitrosative stress, as indicated by higher iNOS and NADPH oxidase subunit gp91phox levels, correlating with increased protein nitration, gauged by nitrotyrosine immunostaining. Notably, we also observed lower neurofilaments immunostaining in A20 KO brains, suggesting higher susceptibility to axonal injury. Importantly, A20 HT brains showed an intermediate phenotype, exhibiting considerable, albeit not statistically significant, increase in markers of basal inflammation when compared to WT. Conclusions: This is the first characterization of spontaneous neuroinflammation caused by total or partial loss of A20, suggesting its key role in maintenance of nervous tissue homeostasis, particularly control of inflammation. Remarkably, mere partial loss of A20 was sufficient to cause chronic, spontaneous low-grade cerebral inflammation, which could sensitize these animals to neurodegenerative diseases. These findings carry strong clinical relevance in that they question implication of identified A20 SNPs that lower A20 expression/function (phenocopying A20 HT mice) in the pathophysiology of neuroinflammatory diseases
Dynamical Measurements of Black Hole Masses in Four Brightest Cluster Galaxies at 100 Mpc
We present stellar kinematics and orbit superposition models for the central
regions of four Brightest Cluster Galaxies (BCGs), based upon integral-field
spectroscopy at Gemini, Keck, and McDonald Observatories. Our integral-field
data span radii from < 100 pc to tens of kpc. We report black hole masses,
M_BH, of 2.1 +/- 1.6 x 10^10 M_Sun for NGC 4889, 9.7 + 3.0 - 2.6 x 10^9 M_Sun
for NGC 3842, and 1.3 + 0.5 - 0.4 x 10^9 M_Sun for NGC 7768. For NGC 2832 we
report an upper limit of M_BH < 9 x 10^9 M_Sun. Stellar orbits near the center
of each galaxy are tangentially biased, on comparable spatial scales to the
galaxies' photometric cores. We find possible photometric and kinematic
evidence for an eccentric torus of stars in NGC 4889, with a radius of nearly 1
kpc. We compare our measurements of M_BH to the predicted black hole masses
from various fits to the relations between M_BH and stellar velocity
dispersion, luminosity, or stellar mass. The black holes in NGC 4889 and NGC
3842 are significantly more massive than all dispersion-based predictions and
most luminosity-based predictions. The black hole in NGC 7768 is consistent
with a broader range of predictions.Comment: 24 pages, 18 figures. Accepted for publication in Ap
Stellar Disks in Aquarius Dark Matter Haloes
We investigate the gravitational interactions between live stellar disks and
their dark matter halos, using LCDM haloes similar in mass to that of the Milky
Way taken from the Aquarius Project. We introduce the stellar disks by first
allowing the haloes to respond to the influence of a growing rigid disk
potential from z = 1.3 to z = 1.0. The rigid potential is then replaced with
star particles which evolve self-consistently with the dark matter particles
until z = 0.0. Regardless of the initial orientation of the disk, the inner
parts of the haloes contract and change from prolate to oblate as the disk
grows to its full size. When the disk normal is initially aligned with the
major axis of the halo at z=1.3, the length of the major axis contracts and
becomes the minor axis by z=1.0. Six out of the eight disks in our main set of
simulations form bars, and five of the six bars experience a buckling
instability that results in a sudden jump in the vertical stellar velocity
dispersion and an accompanying drop in the m=2 Fourier amplitude of the disk
surface density. The bars are not destroyed by the buckling but continue to
grow until the present day. Bars are largely absent when the disk mass is
reduced by a factor of two or more; the relative disk-to-halo mass is therefore
a primary factor in bar formation and evolution. A subset of the disks is
warped at the outskirts and contains prominent non-coplanar material with a
ring-like structure. Many disks reorient by large angles between z=1 and z=0,
following a coherent reorientation of their inner haloes. Larger reorientations
produce more strongly warped disks, suggesting a tight link between the two
phenomena. The origins of bars and warps appear independent: some disks with
strong bars show no disturbances at the outskirts, while the disks with the
weakest bars show severe warps.Comment: 19 pages, 13 figures, accepted MNRAS; fixed compatibility problem in
figures 8,
A geometric approach to time evolution operators of Lie quantum systems
Lie systems in Quantum Mechanics are studied from a geometric point of view.
In particular, we develop methods to obtain time evolution operators of
time-dependent Schrodinger equations of Lie type and we show how these methods
explain certain ad hoc methods used in previous papers in order to obtain exact
solutions. Finally, several instances of time-dependent quadratic Hamiltonian
are solved.Comment: Accepted for publication in the International Journal of Theoretical
Physic
Theory and phenomenology of two-Higgs-doublet models
We discuss theoretical and phenomenological aspects of two-Higgs-doublet
extensions of the Standard Model. In general, these extensions have scalar
mediated flavour changing neutral currents which are strongly constrained by
experiment. Various strategies are discussed to control these flavour changing
scalar currents and their phenomenological consequences are analysed. In
particular, scenarios with natural flavour conservation are investigated,
including the so-called type I and type II models as well as lepton-specific
and inert models. Type III models are then discussed, where scalar flavour
changing neutral currents are present at tree level, but are suppressed by
either specific ansatze for the Yukawa couplings or by the introduction of
family symmetries. We also consider the phenomenology of charged scalars in
these models. Next we turn to the role of symmetries in the scalar sector. We
discuss the six symmetry-constrained scalar potentials and their extension into
the fermion sector. The vacuum structure of the scalar potential is analysed,
including a study of the vacuum stability conditions on the potential and its
renormalization-group improvement. The stability of the tree level minimum of
the scalar potential in connection with electric charge conservation and its
behaviour under CP is analysed. The question of CP violation is addressed in
detail, including the cases of explicit CP violation and spontaneous CP
violation. We present a detailed study of weak basis invariants which are odd
under CP. A careful study of spontaneous CP violation is presented, including
an analysis of the conditions which have to be satisfied in order for a vacuum
to violate CP. We present minimal models of CP violation where the vacuum phase
is sufficient to generate a complex CKM matrix, which is at present a
requirement for any realistic model of spontaneous CP violation.Comment: v3: 180 pages, 506 references, new chapter 7 with recent LHC results;
referee comments taken into account; submitted to Physics Report
Spectrum of ankylosing spondylitis in Portugal. Development of BASDAI, BASFI, BASMI and mSASSS reference centile charts
The availability of population-specific normative data regarding disease severity measures is essential for patient assessment. The goals of the current study were to characterize the pattern of ankylosing spondylitis (AS) in Portuguese patients and to develop reference centile charts for BASDAI, BASFI, BASMI and mSASSS, the most widely used assessment tools in AS. AS cases were recruited from hospital outpatient clinics, with AS defined according to the modified New York criteria. Demographic and clinical data were recorded. All radiographs were evaluated by two independent experienced readers. Centile charts for BASDAI, BASFI, BASMI and mSASSS were constructed for both genders, using generalized linear models and regression models with duration of disease as independent variable. A total of 369 patients (62.3% male, mean ± (SD) age 45.4 ± 13.2 years, mean ± (SD) disease duration 11.4 ± 10.5 years, 70.7% B27-positive) were included. Family history of AS in a first-degree relative was reported in 17.6% of the cases. Regarding clinical disease pattern, at the time of assessment 42.3% had axial disease, 2.4% peripheral disease, 40.9% mixed disease and 7.1% isolated enthesopatic disease. Anterior uveitis (33.6%) was the most common extra-articular manifestation. The centile charts suggest that females reported greater disease activity and more functional impairment than males but had lower BASMI and mSASSS scores. Data collected through this study provided a demographic and clinical profile of patients with AS in Portugal. The development of centile charts constitutes a useful tool to assess the change of disease pattern over time and in response to therapeutic interventions
Ultra high molecular weight polyethylene and its reinforcement with Carbon Nanotubes in Medical Devices
This chapter discusses the advantages and complexities of ultra high molecular weight polyethylene(UHMWPE) when used as a bearing material for total joint arthroplasty (TJA) and total knee arthroplasty(TKA). The UHMWPE internal structure and its mechanical response depend strongly on a diversity offactors that include radiation crosslinking, fiber reinforcement, and the addition of antioxidants such asVitamin E or Vitamin C. All these manufacturing procedures induce morphological changes andsimultaneously alter the mechanical properties of UHMWPE. The importance of UHMWPE on arthroplasty,including the advantages, the limitations and the strategies devised to overcome the knowndrawbacks are discussed in the first section. The following sections revise and discuss thebiocompatibility, the manufacturing processes, the tribological behaviour, the aging by oxidation andirradiation of UHMWPE and UHMWPE-CNT nanocomposites. The last section analyses the viscoelasticbehavior of UHMWPE and its implications on the long-term survival of total joint arthroplasty
The Star Formation History and Dust Content in the Far Outer Disc of M31
We present a detailed analysis of two fields located 26 kpc (~5 scalelengths)
from the centre of M31. One field samples the major axis populations--the Outer
Disc field--while the other is offset by ~18' and samples the Warp in the
stellar disc. The CMDs based on HST/ACS imaging reach old main-sequence
turn-offs (~12.5 Gyr). We apply the CMD-fitting technique to the Warp field to
reconstruct the star formation history (SFH). We find that after undergoing
roughly constant SF until about 4.5 Gyr ago, there was a rapid decline in
activity and then a ~1.5 Gyr lull, followed by a strong burst lasting 1.5 Gyr
and responsible for 25% of the total stellar mass in this field. This burst
appears to be accompanied by a decline in metallicity which could be a
signature of the inflow of metal-poor gas. The onset of the burst (~3 Gyr ago)
corresponds to the last close passage of M31 and M33 as predicted by detailed
N-body modelling, and may have been triggered by this event. We reprocess the
deep M33 outer disc field data of Barker et al. (2011) in order to compare
consistently-derived SFHs. This reveals a similar duration burst that is
exactly coeval with that seen in the M31 Warp field, lending further support to
the interaction hypothesis. The complex SFHs and the smoothly-varying
age-metallicity relations suggest that the stellar populations observed in the
far outer discs of both galaxies have largely formed in situ rather than
migrated from smaller galactocentric radii. The strong differential reddening
affecting the CMD of the Outer Disc field prevents derivation of the SFH.
Instead, we quantify this reddening and find that the fine-scale distribution
of dust precisely follows that of the HI gas. This indicates that the outer HI
disc of M31 contains a substantial amount of dust and therefore suggests
significant metal enrichment in these parts, consistent with inferences from
our CMD analysis.Comment: Abstract shortened. 17 pages, 12 figures (+ 6 pages & 5 figures in
Appendix). MNRAS, in pres
Patient Concerns Inventory for head and neck cancer: Brazilian cultural adaptation
Objective: The purpose of this study was to translate, culturally validate and evaluate the Patients Concerns Inventory - Head and Neck (PCI- H&N) in a consecutive series of Brazilian patients. Methods: This study included adult patients treated for upper aerodigestive tract (UADT) cancer. The translation and cultural adaptation of the PCI–H&N followed internationally accepted guidelines and included a pretest sample of patients that completed the first Brazilian-Portuguese version of the PCI. The use/feasibility/acceptability of the PCI was tested subsequently in a consecutive series of UADT cancer patients that completed the final Brazilian-Portuguese version of the PCI and a Brazilian-Portuguese version of the University of Washington Quality of Life Questionnaire (UW-QOL). Associations between physical and socio emotional composite scores from the UW-QOL and PCI were analyzed. Results: Twenty patients participated in the pretest survey (translation and cultural adaptation process), and 84 patients were analysed in the cultural validation study. Issues most selected were: fear of cancer returning, dry mouth, chewing/eating, speech/voice/being understood, swallowing, dental health/teeth, anxiety, fatigue/tiredness, taste and fear of adverse events. The three specialists most selected were speech therapist, dentist and psychologist. Statistically significant relationships between PCI and UW-QOL were found. Conclusions: The translation and cultural adaptation of the PCI for Brazilian-Portuguese language was successful, and the results demonstrate its feasibility and usefulness, making this a valuable tool for use within the Brazilian H&N cancer population
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