854 research outputs found
Osteovascular Conflicts in the Neck Region and Cerebrovascular Events: Illustrative Cases and Literature Review.
Literature Review.
Abnormal bone structures in the neck can cause headache, neck pain, and difficulty swallowing, but also cerebrovascular events. We introduce the term "osteovascular conflicts" to describe this phenomenon. The objective of this study was to conduct a literature review of such conflicts involving the anterior and posterior cerebral circulation. Furthermore, we aimed at presenting additional illustrative cases from our institution both for increasing awareness for unusual osteovascular conflicts, and for assessing the practice and care of such patients.
We focused on osteovascular conflicts in the neck leading to cerebrovascular events related to an abnormal bone structure causing arterial or venous compression, dissection, and/or occlusion. We excluded pure vascular forms without cerebrovascular repercussions. Our PubMed/MEDLINE search for articles published in any language and for which an English abstract was available (from 1966 to 2022) included Eagle's neurovascular, bow hunter's syndrome, and golfer's stroke, excluding trauma-induced artery dissections or compressions and those concerning systemic bone disorders. We also provided illustrative cases collected by the authors.
All studies were either case reports or small case series. We found 82 cases of Eagle's neurovascular, 258 of bow hunter's syndrome, and 17 golfer's stroke cases. Mean ages were 52, 48, and 47 years, respectively. Male predominance was evident: 81% for Eagle's, 74% for bow hunter's, and 93% for golfer's.
Osteovascular conflicts are rare but important causes of cerebrovascular events and often go unrecognised. A greater awareness of cerebrovascular symptoms related to these conflicts can facilitate early diagnosis and treatment
The pharmacology of recombinant hirudin, a new anticoagulant
A new anticoagulant, recombinant hirudin, was given to healthy volunteers (5 per test dose) in single .intravenous doses of 0,01, 0,02, 0,04, 0,07 and 0,1 mg/kg to study its anticoagulant effects, how it was tolerated and its pharmacokinetics. Hirudin proved to be a potent anticoagulant with important effects on thrombin (increase in thrombin time and partial thromboplastin time). The maximum pharmacodynamic effect was achieved with the 0,07 mg/kg dose, and upwards. All doses of the compound were tolerated without sideeffects. The mean elimination half-life is about 1 hour. Mean total clearance and volume of distribution are approximately 190 ml/min and 14 I, respectively. Hirudin obeys first-order pharmacokinetics
Dynamic Image-Based Modelling of Kidney Branching Morphogenesis
Kidney branching morphogenesis has been studied extensively, but the
mechanism that defines the branch points is still elusive. Here we obtained a
2D movie of kidney branching morphogenesis in culture to test different models
of branching morphogenesis with physiological growth dynamics. We carried out
image segmentation and calculated the displacement fields between the frames.
The models were subsequently solved on the 2D domain, that was extracted from
the movie. We find that Turing patterns are sensitive to the initial conditions
when solved on the epithelial shapes. A previously proposed diffusion-dependent
geometry effect allowed us to reproduce the growth fields reasonably well, both
for an inhibitor of branching that was produced in the epithelium, and for an
inducer of branching that was produced in the mesenchyme. The latter could be
represented by Glial-derived neurotrophic factor (GDNF), which is expressed in
the mesenchyme and induces outgrowth of ureteric branches. Considering that the
Turing model represents the interaction between the GDNF and its receptor RET
very well and that the model reproduces the relevant expression patterns in
developing wildtype and mutant kidneys, it is well possible that a combination
of the Turing mechanism and the geometry effect control branching
morphogenesis
Use of electrostatic gridded lenses in the laser ion source at CERN
The GEL LEBT provides high efficiency beam transport and matching to the RFQ acceptance in the 4-dimensional phase space. The rms emittance growth is relatively small even for 60 kV extraction voltage. The number of particles occupying the 4-D RFQ acceptance strongly depends from the beam emittance at the entrance of the GEL LEBT. In most realistic case with the input emittance equal to the measured one, which is 320 p×mm×mrad (4×rms emittance) the number of particles inside the 4-D space with the projection emittance of 200 p×mm×mrad is 38% at the entrance and 35% at the output of GEL LEBT, which means that LEBT does not practically destroy beam emittance. The experimental value of the yield to the double aperture is 35% and confirms the expected performance of the GEL LEBT
Statistical Theory of Spin Relaxation and Diffusion in Solids
A comprehensive theoretical description is given for the spin relaxation and
diffusion in solids. The formulation is made in a general
statistical-mechanical way. The method of the nonequilibrium statistical
operator (NSO) developed by D. N. Zubarev is employed to analyze a relaxation
dynamics of a spin subsystem. Perturbation of this subsystem in solids may
produce a nonequilibrium state which is then relaxed to an equilibrium state
due to the interaction between the particles or with a thermal bath (lattice).
The generalized kinetic equations were derived previously for a system weakly
coupled to a thermal bath to elucidate the nature of transport and relaxation
processes. In this paper, these results are used to describe the relaxation and
diffusion of nuclear spins in solids. The aim is to formulate a successive and
coherent microscopic description of the nuclear magnetic relaxation and
diffusion in solids. The nuclear spin-lattice relaxation is considered and the
Gorter relation is derived. As an example, a theory of spin diffusion of the
nuclear magnetic moment in dilute alloys (like Cu-Mn) is developed. It is shown
that due to the dipolar interaction between host nuclear spins and impurity
spins, a nonuniform distribution in the host nuclear spin system will occur and
consequently the macroscopic relaxation time will be strongly determined by the
spin diffusion. The explicit expressions for the relaxation time in certain
physically relevant cases are given.Comment: 41 pages, 119 Refs. Corrected typos, added reference
The RNA chaperone Hfq is essential for the virulence of Salmonella typhimurium
The RNA chaperone, Hfq, plays a diverse role in bacterial physiology beyond its original role as a host factor required for replication of Qβ RNA bacteriophage. In this study, we show that Hfq is involved in the expression and secretion of virulence factors in the facultative intracellular pathogen, Salmonella typhimurium. A Salmonella hfq deletion strain is highly attenuated in mice after both oral and intraperitoneal infection, and shows a severe defect in invasion of epithelial cells and a growth defect in both epithelial cells and macrophages in vitro. Surprisingly, we find that these phenotypes are largely independent of the previously reported requirement of Hfq for expression of the stationary phase sigma factor, RpoS. Our results implicate Hfq as a key regulator of multiple aspects of virulence including regulation of motility and outer membrane protein (OmpD) expression in addition to invasion and intracellular growth. These pleiotropic effects are suggested to involve a network of regulatory small non-coding RNAs, placing Hfq at the centre of post-transcriptional regulation of virulence gene expression in Salmonella. In addition, the hfq mutation appears to cause a chronic activation of the RpoE-mediated envelope stress response which is likely due to a misregulation of membrane protein expression
Organizational and Leadership Implications for Transformational Development
Transformational development is a concept of change that originated in the Christian context but has now become generally used in the work of both secular and faith-based organizations. The growing use of the concept by organizations that are fundamentally different has naturally led to some confusion about what the concept means and what it takes to effectively implement it. In this article, we describe the key features of the concept and how they are important in determining the organizational requirements for its effective implementation. Drawing on a few cases, the paper highlights the centrality of faith in transformational development work
Search for Higgs bosons decaying to tautau pairs in ppbar collisions at sqrt(s) = 1.96 TeV
We present a search for the production of neutral Higgs bosons decaying into
tautau pairs in ppbar collisions at a center-of-mass energy of 1.96 TeV. The
data, corresponding to an integrated luminosity of 5.4 fb-1, were collected by
the D0 experiment at the Fermilab Tevatron Collider. We set upper limits at the
95% C.L. on the product of production cross section and branching ratio for a
scalar resonance decaying into tautau pairs, and we then interpret these limits
as limits on the production of Higgs bosons in the minimal supersymmetric
standard model (MSSM) and as constraints in the MSSM parameter space.Comment: 7 pages, 5 figures, submitted to PL
Measurement of the photon-jet production differential cross section in collisions at \sqrt{s}=1.96~\TeV
We present measurements of the differential cross section dsigma/dpT_gamma
for the inclusive production of a photon in association with a b-quark jet for
photons with rapidities |y_gamma|< 1.0 and 30<pT_gamma <300 GeV, as well as for
photons with 1.5<|y_gamma|< 2.5 and 30< pT_gamma <200 GeV, where pT_gamma is
the photon transverse momentum. The b-quark jets are required to have pT>15 GeV
and rapidity |y_jet| < 1.5. The results are based on data corresponding to an
integrated luminosity of 8.7 fb^-1, recorded with the D0 detector at the
Fermilab Tevatron Collider at sqrt(s)=1.96 TeV. The measured cross
sections are compared with next-to-leading order perturbative QCD calculations
using different sets of parton distribution functions as well as to predictions
based on the kT-factorization QCD approach, and those from the Sherpa and
Pythia Monte Carlo event generators.Comment: 10 pages, 9 figures, submitted to Phys. Lett.
Limits on anomalous trilinear gauge boson couplings from WW, WZ and Wgamma production in pp-bar collisions at sqrt{s}=1.96 TeV
We present final searches of the anomalous gammaWW and ZWW trilinear gauge
boson couplings from WW and WZ production using lepton plus dijet final states
and a combination with results from Wgamma, WW, and WZ production with leptonic
final states. The analyzed data correspond to up to 8.6/fb of integrated
luminosity collected by the D0 detector in pp-bar collisions at sqrt{s}=1.96
TeV. We set the most stringent limits at a hadron collider to date assuming two
different relations between the anomalous coupling parameters
Delta\kappa_\gamma, lambda, and Delta g_1^Z for a cutoff energy scale Lambda=2
TeV. The combined 68% C.L. limits are -0.057<Delta\kappa_\gamma<0.154,
-0.015<lambda<0.028, and -0.008<Delta g_1^Z<0.054 for the LEP parameterization,
and -0.007<Delta\kappa<0.081 and -0.017<lambda<0.028 for the equal couplings
parameterization. We also present the most stringent limits of the W boson
magnetic dipole and electric quadrupole moments.Comment: 10 pages, 5 figures, submitted to PL
- …