288 research outputs found
Misdiagnosis of acute subarachnoid hemorrhage in the era of multimodal diagnostic options
No full textPatients suffering from aneurysmatic Subarachnoid Hemorrhage (SAH) may present with a variety of symptoms. The aim of this study is to evaluate the spectrum of misdiagnoses and to analyze the significance of delay of correct diagnosis on the clinical outcome
Distortions of parton distributions due to multiquark effects
No full textIt has been observed that the momentum distributions of partons in bound nuclei are distorted relative to those of free protons and neutrons. This phenomenon was first observed in deep inelastic scattering experiments with muon and neutrino beams on nuclear targets and is known as the EMC effect. Similar phenomena have been observed in other high energy interactions such as the Drell-Yan process, the hadroproduction of direct photons, and the resonance production of charmonium and bottomonium states. In this work we investigate the possibility that these effects are predominantly of partonic origin. Standard nuclear quantum mechanics predicts that there is a non-zero probability for bound nucleons to overlap forming complex color singlets. We examine whether the observed EMC-type effects can be attributed to the difference between the parton momentum distributions in such clusters and those in single nucleons. We present a systematic way of determining these distributions in the Bjorken scaling limit and of estimating the average number of multiquark clusters in nuclei. The model predicts depletion of the valence quark and enhancement of the ocean quark and gluon components as the cluster baryon number increases. These properties can naturally explain significant features of the high energy behavior of nuclear targets.</p
Predictive anatomical factors for rupture in middle cerebral artery mirror bifurcation aneurysms
No full textOBJECTIVEThe aim of this study was to define predictive factors for rupture of middle cerebral artery (MCA) mirror bifurcation aneurysms.METHODSThe authors retrospectively analyzed the data in patients with ruptured MCA bifurcation aneurysms with simultaneous presence of an unruptured MCA bifurcation mirror aneurysm treated in two neurosurgical centers. The following parameters were measured and analyzed with the statistical software R: neck, dome, and width of both MCA aneurysms—including neck/dome and width/neck ratios, shape of the aneurysms (regular vs irregular), inflow angle of both MCA aneurysms, and the diameters of the bilateral A1 and M1 segments and the frontal and temporal M2 trunks, as well as the bilateral diameter of the internal carotid artery (ICA).RESULTSThe authors analyzed the data of 44 patients (15 male and 29 female, mean age 50.1 years). Starting from the usual significance level of 0.05, the Sidak-corrected significance level is 0.0039. The diameter of the measured vessels was statistically not significant, nor was the inflow angle. The size of the dome was highly significant (p = 0.0000069). The size of the neck (p = 0.0047940) and the width of the aneurysms (p = 0.0056902) were slightly nonsignificant at the stated significance level of 0.0039. The shape of the aneurysms was bilaterally identical in 22 cases (50%). In cases of asymmetrical presentation of the aneurysm shape, 19 (86.4%) ruptured aneurysms were irregular and 3 (13.6%) had a regular shape (p = 0.001).CONCLUSIONSIn this study the authors show that the extraaneurysmal flow dynamics in mirror aneurysms are nonsignificant, and the aneurysmal geometry also does not seem to play a role as a predictor for rupture. The only predictors for rupture were size and shape of the aneurysms. It seems as though under the same conditions, one of the two aneurysms suffers changes in its wall and starts growing in a more or less stochastic manner. Newer imaging methods should enable practitioners to see which aneurysm has an unstable wall, to predict the rupture risk. At the moment one can only conclude that in cases of MCA mirror aneurysms the larger one, with or without shape irregularities, is the unstable aneurysm and that this is the one that needs to be treated.</jats:sec
Pituitary stalk duplication in ventral-dorsal direction in a patient with pituitary gland adenoma and aqueductal stenosis
No full textClinical management of a ruptured intracranial aneurysm
No full textBackgroundIntracranial hemorrhage due to a ruptured aneurysm is one of the most serious neurosurgical emergencies. The patient mostly presents with severe headaches and neurological deterioration. A rapid diagnosis and an interdisciplinary approach play a major role in the fate of these patients. The treatment can vary from endovascular to surgical and must be carefully and individually planned. Neurovascular expertise and an interdisciplinary approach are of vital importance and obligatory for the best possible outcome.MethodsIn this narrative review, we scrutinize the current literature and discuss the actual data and guidelines in order to emphasize the importance of the interdisciplinary expertise and approach in patients with ruptured intracranial aneurysm.ResultsThe current approach to patients with ruptured aneurysm is inhomogeneous and often ineffective due to internal disputes between different disciplines. Although there is plenty of literature and hard evidence to “show the way,” many still choose to base their decisions on personal experience or opinion.ConclusionsEvery ruptured brain aneurysm should be approached in an interdisciplinary manor and treated according to the current evidence and guidelines
Interdisciplinary Therapeutic Approaches to Atypical and Malignant Meningiomas
No full textMeningiomas have the highest incidence among brain tumors. In contrast to benign tumors that constitute the majority of this tumor entity, the treatment of aggressive meningiomas (WHO Grade 2 and 3) is more challenging, requiring gross total removal of the tumor and the affected dura and adjuvant radiotherapy. Sometimes the location and/or the configuration of the tumor do not favor radical surgical resection without endangering the patient’s clinical condition after surgery and pharmacological therapy has, until now, not been proven to be a reliable alternative. Discussion: In this narrative review, we discuss the current literature with respect to the management of meningiomas, discussing the importance of the grade of resection in the overall prognosis of the patient and in the planning of adjuvant therapy. Conclusions: According to the location and size of the tumor, radical resection should be taken into consideration. In patients with aggressive meningiomas, adjuvant radiotherapy should be performed after surgery. In cases of skull base meningiomas, a maximal, though safe, resection should take place before adjuvant therapy. An interdisciplinary approach is beneficial for patients with primary or recurrent meningioma
The inferior frontal gyrus and cough
No full textWe present a case of a patient with a tumor close to the right inferior frontal gyrus. The only symptom this patient had was a disturbing dry cough. After removal of the tumor the cough disappeared immediately. Review of the literature showed that there is a control center of voluntary cough in the right inferior frontal gyrus. Our case suggests that there might be such a center, which can be affected by a tumor close to it
First observation of the decay Bs0→K*0K*0
No full textThe first observation of the decay B0s→K∗0K∗0 is reported using 35 pb−1 of data collected by LHCb in proton–proton collisions at a centre-of-mass energy of 7 TeV. A total of 49.8±7.5 B0s→(K+π−)(K−π+) events are observed within ±50 MeV/c2 of the B0s mass and 746 MeV/c2 < mKπ < 1046 MeV/c2, mostly coming from a resonant B0s→K∗0K∗0 signal. The branching fraction and the CP-averaged K∗0 longitudinal polarization fraction are measured to be B(B0s→K∗0K∗0)=(2.81±0.46(stat.)±0.45(syst.)±0.34(fs/ fd))×10−5 and fL =0.31±0.12(stat.)±0.04(syst.)
Effective lifetime measurements in the B-s(0) -> K+K-, B-0 -> K+pi(-) and B-s(0) -> pi K-+(-) decays
No full textMeasurements of the effective lifetimes in the View the MathML source, B0→K+π− and View the MathML source decays are presented using 1.0 fb−1 of pp collision data collected at a centre-of-mass energy of 7 TeV by the LHCb experiment. The analysis uses a data-driven approach to correct for the decay time acceptance.
This is the most precise determination to date of the effective lifetime in the View the MathML source decay and provides constraints on contributions from physics beyond the Standard Model to the View the MathML source mixing phase and the width difference ΔΓs
Sums, Differences and Dilates
No full textGiven a set of integers and an integer , write for the set . Hanson and Petridis showed that if then . At a presentation of this result, Petridis stated that the highest known value for (bounded above by 2.95) was . We show that, for all , there exist and with but with .
Further, we analyse a method of Ruzsa, and generalise it to give continuous analogues of the sizes of sumsets, differences and dilates. We apply this method to a construction of Hennecart, Robert and Yudin to prove that, for all , there exists a set with but with .
The second author would like to thank E. Papavassilopoulos for useful discussions about how to improve the efficiency of his computer searches
- …
