Additional ultrasound capabilities for local haemodynamically significant carotid deformity: a one-stage observational study

Background. Despite a wide range of studies, no consensus has been reached on the relative weight of ultrasound parameters for assessing local haemodynamically significant carotid deformations.Objectives. To estimate a diagnostic value for an additional multiparametric ultrasound parameter for local haemodynamically significant carotid deformations.Methods. In the first phase, 388 patients underwent an outpatient multiparametric ultrasound examination of the carotid arteries. The study involved patients of the age of 18 and older with a primary referral for carotid ultrasound by a resident physician, neurologist or cardiologist in order to rule out a carotid pathology. As a supplement to the main haemodynamic significance assessment parameters, we introduced an additional metric — the deformity coefficient – in order to diagnose carotid abnormalities. Based on the first phase results, two cohorts were selected. Cohort 1 (control) consisted of patients with no abnormalities in multiparametric carotid ultrasound. Cohort 2 consisted of patients with isolated unilateral internal carotid artery deformities at no haemodynamically significant stenosis of common and internal carotid arteries in multiparametric carotid ultrasound. In the second phase, the patients underwent transcranial duplex sonography of the middle cerebral arteries, in order to detect regional haemodynamically significant internal carotid artery deformities.Results. Mathematical modelling of abnormal arteries produced the empirical upper deformity coefficient thresholds to distinguish acute angulation. This value is >1.41 for C-shaped and >1.34 — for S-shaped curves.Subsequent statistical analysis revealed a clear positive correlation between angulation and the deformity coefficient at a p < 0.01 significance level. More acute angulation corresponds to higher coefficient values.The Spearman correlation between the deformity coefficient and blood flow asymmetry values for middle cerebral artery was 0.89. This defines a significant positive correlation (higher deformity coefficient corresponds to higher blood flow asymmetry) at a p < 0.01 significance level.Conclusion. The deformity coefficient is an additional ultrasound parameter for assessing local haemodynamically significant carotid abnormalities

Comparison of forward and backward pp pair knockout in He-3(e, e \u27 pp)n

Measuring nucleon-nucleon short range correlations (SRCs) has been a goal of the nuclear physics community for many years. They are an important part of the nuclear wave function, accounting for almost all of the high-momentum strength. They are closely related to the EMC effect. While their overall probability has been measured, measuring their momentum distributions is more difficult. In order to determine the best configuration for studying SRC momentum distributions, we measured the He-3(e, e\u27 pp)n reaction, looking at events with high-momentum protons (p(p) \u3e 0.35 GeV/c) and a low-momentum neutron (p(n) \u3c 0.2 GeV/c). We examined two angular configurations: either both protons emitted forward or one proton emitted forward and one backward (with respect to the momentum transfer, ). The measured relative momentum distribution of the events with one forward and one backward proton was much closer to the calculated initial-state pp relative momentum distribution, indicating that this is the preferred configuration for measuring SRC

МЕТОДОЛОГИЧЕСКИЕ АСПЕКТЫ ВИЗУАЛИЗАЦИИ КОРОНАРНЫХ АРТЕРИЙ ПРИ ТРАНСТОРАКАЛЬНОЙ ЭХОКАРДИОГРАФИИ

The transthoracic echocardiography made by multifrequency probes with support of the mode of the second harmonic imaging, is a competitive method for visualization of the main coronary arteries and allows to estimate coronary blood flow with high quality. Of course, the method has considerable restrictions, most important of which is the low spatial resolution of a method, due to small acoustic window. Because of this the transthoracic visualization of coronary arteries perhaps will not become the leading method of anatomic reconstruction of separately taken coronary artery and especially all coronary arteries system. However uniqueness and indisputable advantage of this method is an opportunity to noninvasively estimate a coronary blood flow both once, and in dynamics.Трансторакальная эхокардиография, выполненная с помощью мультичастотных датчиков с поддержкой режима второй тканевой гармоники, является конкурентоспособным методом для визуализации магистральных коронарных артерий и позволяет качественно оценить спектр коронарного кровотока в них. Безусловно, у метода есть значительные ограничения, самой главной из которых является низкая пространственная разрешающая способность метода из-за небольшого акустического окна. Именно из-за этого трансторакальное исследование коронарных артерий, по всей видимости, не станет лидирующим методом анатомической реконструкции отдельно взятой коронарной артерии и тем более всего коронарного русла. Однако уникальностью и неоспоримым преимуществом данного метода является  возможность неинвазивно оценить коронарный кровоток как однократно, так и в динамике

Search for QCD instanton-induced processes at HERA in the high-Q2{Q^2} domain

Signals of QCD instanton-induced processes are searched for in neutral current deep-inelastic scattering at the electron-proton collider HERA in the kinematic region defined by the Bjorken-scaling variable x > 10−3, the inelasticity 0.2 < y < 0.7 and the photon virtuality 150 < Q2 < 15000 GeV2. The search is performed using H1 data corresponding to an integrated luminosity of 351 pb−1. No evidence for the production of QCD instanton-induced events is observed. Upper limits on the cross section for instanton-induced processes between 1.5 pb and 6 pb, at 95% confidence level, are obtained depending on the kinematic domain in which instantons could be produced. Compared to earlier publications, the limits are improved by an order of magnitude and for the first time are challenging predictions

Transverse Polarization of Σ+ (1189) in Photoproduction on a Hydrogen Target in CLAS

Experimental results on the Σ+(1189) hyperon transverse polarization in photoproduction on a hydrogen target using the CLAS detector at Jefferson Laboratory are presented. The Σ+(1189) was reconstructed in the exclusive reaction γ+p→K0S+Σ+(1189) via the Σ+→pπ0 decay mode. The K0S was reconstructed in the invariant mass of two oppositely charged pions with the π0 identified in the missing mass of the detected pπ+π− final state. Experimental data were collected in the photon energy range Eγ=1.0 –3.5 GeV (√s range 1.66–2.73 GeV). We observe a large negative polarization of up to 95% . As the mechanism of transverse polarization of hyperons produced in unpolarized photoproduction experiments is still not well understood, these results will help to distinguish between different theoretical models on hyperon production and provide valuable information for the searches of missing baryon resonances

Measurement of the Neutron F2 Structure Function Via Spectator Tagging with CLAS

We report on the first measurement of the F2 structure function of the neutron from the semi-inclusive scattering of electrons from deuterium, with low-momentum protons detected in the backward hemisphere. Restricting the momentum of the spectator protons to ≲ 100MeV/c and their angles to ≳ 100° relative to the momentum transfer allows an interpretation of the process in terms of scattering from nearly on-shell neutrons. The Fn2 data collected cover the nucleon-resonance and deep-inelastic regions over a wide range of Bjorken x for 0.65 \u3c Q2 \u3c 4.52 GeV2, with uncertainties from nuclear corrections estimated to be less than a few percent. These measurements provide the first determination of the neutron to proton structure function ratio Fn2/Fp2 at ≲ 0.2 ≲ x ≲ 0.8 with little uncertainty due to nuclear effects. 2012 American Physical Society

Comparison of Forward and Backward \u3ci\u3epp\u3c/i\u3e Pair Knockout in \u3csup\u3e3\u3c/sup\u3eHe(e,e\u27pp)n

Measuring nucleon-nucleon short range correlations (SRCs) has been a goal of the nuclear physics community for many years. They are an important part of the nuclear wave function, accounting for almost all of the high-momentum strength. They are closely related to the EMC effect. While their overall probability has been measured, measuring their momentum distributions is more difficult. In order to determine the best configuration for studying SRC momentum distributions, we measured the 3He(e,e\u27pp)n reaction, looking at events with high-momentum protons (pp \u3e 0.35 GeV/c) and a low-momentum neutron (pn \u3c 0.2 GeV/c). We examined two angular configurations: either both protons emitted forward or one proton emitted forward and one backward (with respect to the momentum transfer, q). The measured relative momentum distribution of the events with one forward and one backward proton was much closer to the calculated initial-state pp relative momentum distribution, indicating that this is the preferred configuration for measuring SRC. ©2012 American Physical Societ

A comparison of forward and backward pp pair knockout in 3He(e,e'pp)n

Measuring nucleon-nucleon Short Range Correlations (SRC) has been a goal of the nuclear physics community for many years. They are an important part of the nuclear wavefunction, accounting for almost all of the high-momentum strength. They are closely related to the EMC effect. While their overall probability has been measured, measuring their momentum distributions is more difficult. In order to determine the best configuration for studying SRC momentum distributions, we measured the $^3$He$(e,e'pp)n$ reaction, looking at events with high momentum protons ($p_p > 0.35$ GeV/c) and a low momentum neutron ($p_n< 0.2$ GeV/c). We examined two angular configurations: either both protons emitted forward or one proton emitted forward and one backward (with respect to the momentum transfer, $\vec q$). The measured relative momentum distribution of the events with one forward and one backward proton was much closer to the calculated initial-state $pp$ relative momentum distribution, indicating that this is the preferred configuration for measuring SRC.Comment: 8 pages, 9 figures, submitted to Phys Rev C. Version 2 incorporates minor corrections in response to referee comment