Central μ+μ−\mu^{+}\mu^{-} production via photon-photon fusion in proton-proton collisions with proton dissociation

We present a formalism which uses fluxes of equivalent photons including transverse momenta of the intermediate photons. The formalism reminds the familiar $k_t$-factorization approach used, e.g., to study the two-photon production of $c\bar{c}$ or $b\bar{b}$ pairs. The results of the new method are compared with those obtained using the code LPAIR, and a good agreement is obtained. The inclusion of the photon transverse momenta is necessary in studies of correlation observables. We present distributions for the dimuon invariant mass, transverse momentum of the muon pair and relative azimuthal angle between muons separately for elastic-elastic, elastic-inelastic, inelastic-elastic and inelastic-inelastic mechanisms. For typical experimental cuts all mechanisms give similar contributions. The results are shown for different sets of cuts relevant for the LHC experiments. The cross sections in different regions of phase space depend on $F_2$ structure function in different regions of $x$ and $Q^2$. A comment on $F_2$ is made.Comment: 24 pages, 36 figures, 2 table

Salsolinol: an Unintelligible and Double-Faced Molecule—Lessons Learned from In Vivo and In Vitro Experiments

Salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline) is a tetrahydroisoquinoline derivative whose presence in humans was first detected in the urine of Parkinsonian patients on l-DOPA (l-dihydroxyphenylalanine) medication. Thus far, multiple hypotheses regarding its physiological/pathophysiological roles have been proposed, especially related to Parkinson’s disease or alcohol addiction. The aim of this review was to outline studies related to salsolinol, with special focus on in vivo and in vitro experimental models. To begin with, the chemical structure of salsolinol together with its biochemical implications and the role in neurotransmission are discussed. Numerous experimental studies are summarized in tables and the most relevant ones are stressed. Finally, the ability of salsolinol to cross the blood–brain barrier and its possible double-faced neurobiological potential are reviewed.Peer reviewe

Classification system of the tibiofibular syndesmosis blood supply and its clinical relevance

Due to the lack of anatomical studies concerning complexity of the tibiofibular syndesmosis blood supply, density of blood vessels with further organization of syndesmotic vascular variations is presented in clinically relevant classification system. The material for the study was obtained from cadaveric dissections. We dissected 50 human ankles observing different types of arterial blood supply. Our classification system is based on the vascular variations of the anterior aspect of tibiofibular syndesmosis and corresponds with vascular density. According to our study the mean vascular density of tibiofibular syndesmosis is relatively low (4.4%) and depends on the type of blood supply. The highest density was observed among ankles with complete vasculature and the lowest when lateral anterior malleolar artery was absent (5.8% vs. 3.5%, respectively). Awareness of various types of tibiofibular syndesmosis arterial blood supply is essential for orthopedic surgeons who operate in the ankle region and radiologists for the anatomic evaluation of this area. Knowledge about possible variations along with relatively low density of vessels may contribute to modification of treatment approach by the increase of the recommended time of syndesmotic screw stabilization in order to prevent healing complications

Diagnostic value of cerebral perfusion scintigraphy in evaluation of intracranial arteriovenous malformations - preliminary report

BACKGROUND: Arteriovenous malformations (AVM) markedly alter the distribution of the regional cerebral blood flow, as they consist of abnormal arteries and veins with no resistance vessels between them. The aim of this study was to the evaluate diagnostic utility of cerebral perfusion scintigraphy (dynamic phase and SPECT) in patients with AVM. MATERIAL AND METHODS: Nineteen patients were examined. All the patients had been previously diagnosed with AVM and qualified for intravascular embolization. Brain scintigraphy was performed with 99mTc-ECD and included dynamic phase and SPECT imaging. The regional blood flow was evaluated visually and semi quantitatively, based on comparison between the activity in the two symmetrical regions of interest. Differences higher than 10% were considered significant. Cerebral angiography combined with intravascular embolization was carried out after a scitigraphic examination. RESULTS: Based on angiograms, the diameter of the AVM nidus was estimated and varied from 1.0 cm to 9.0 cm. In 13 cases, AVM were visible in the dynamic scintigraphy as areas of increased tracer activity. In each case, SPECT images showed the AVM nidus as a region of decreased tracer accumulation. Hypoperfusion in the brain tissue adjacent to the nidus was seen in 15 subjects. In one patient cerebellar diaschisis was present. The average ratio of activity in the region of AVM to activity in the normally perfused tissue calculated by semiquantitative analysis was 77.5 ± 10.9%. CONCLUSION: Cerebral perfusion scintigraphy (SPECT images and dynamic scintigraphy) allows one to identify perfusion disturbances caused by the presence of intracranial AVM