Post-carotid stent ultrasound provides critical data to avoid rare but serious complications

SummaryCarotid stenting is a common procedure for revascularization of carotid artery stenosis. In this study, we evaluated the role of carotid ultrasound post carotid stenting. In a retrospective analysis, we identified 45 patients who received post-stent ultrasound. On routine follow-up we measured a range for peak systolic velocity of 33–150cm/s and end diastolic velocity 11–52cm/s. We also identified two cases, where immediate post-stent ultrasound provided critical data that required further intervention, and potentially avoided serious complications

Automatic mapping of atoms across both simple and complex chemical reactions

Mapping atoms across chemical reactions is important for substructure searches, automatic extraction of reaction rules, identification of metabolic pathways, and more. Unfortunately, the existing mapping algorithms can deal adequately only with relatively simple reactions but not those in which expert chemists would benefit from computer's help. Here we report how a combination of algorithmics and expert chemical knowledge significantly improves the performance of atom mapping, allowing the machine to deal with even the most mechanistically complex chemical and biochemical transformations. The key feature of our approach is the use of few but judiciously chosen reaction templates that are used to generate plausible "intermediate" atom assignments which then guide a graph-theoretical algorithm towards the chemically correct isomorphic mappings. The algorithm performs significantly better than the available state-of-the-art reaction mappers, suggesting its uses in database curation, mechanism assignments, and - above all - machine extraction of reaction rules underlying modern synthesis-planning programs

Interhospital Transfer Before Thrombectomy Is Associated With Delayed Treatment and Worse Outcome in the STRATIS Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke).

BACKGROUND: Endovascular treatment with mechanical thrombectomy (MT) is beneficial for patients with acute stroke suffering a large-vessel occlusion, although treatment efficacy is highly time-dependent. We hypothesized that interhospital transfer to endovascular-capable centers would result in treatment delays and worse clinical outcomes compared with direct presentation. METHODS: STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter, observational, single-arm study of real-world MT for acute stroke because of anterior-circulation large-vessel occlusion performed at 55 sites over 2 years, including 1000 patients with severe stroke and treated within 8 hours. Patients underwent MT with or without intravenous tissue plasminogen activator and were admitted to endovascular-capable centers via either interhospital transfer or direct presentation. The primary clinical outcome was functional independence (modified Rankin Score 0-2) at 90 days. We assessed (1) real-world time metrics of stroke care delivery, (2) outcome differences between direct and transfer patients undergoing MT, and (3) the potential impact of local hospital bypass. RESULTS: A total of 984 patients were analyzed. Median onset-to-revascularization time was 202.0 minutes for direct versus 311.5 minutes for transfer patients ( CONCLUSIONS: In this large, real-world study, interhospital transfer was associated with significant treatment delays and lower chance of good outcome. Strategies to facilitate more rapid identification of large-vessel occlusion and direct routing to endovascular-capable centers for patients with severe stroke may improve outcomes. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02239640

Biological effects of exposure to magnetic resonance imaging: an overview

The literature on biological effects of magnetic and electromagnetic fields commonly utilized in magnetic resonance imaging systems is surveyed here. After an introduction on the basic principles of magnetic resonance imaging and the electric and magnetic properties of biological tissues, the basic phenomena to understand the bio-effects are described in classical terms. Values of field strengths and frequencies commonly utilized in these diagnostic systems are reported in order to allow the integration of the specific literature on the bio-effects produced by magnetic resonance systems with the vast literature concerning the bio-effects produced by electromagnetic fields. This work gives an overview of the findings about the safety concerns of exposure to static magnetic fields, radio-frequency fields, and time varying magnetic field gradients, focusing primarily on the physics of the interactions between these electromagnetic fields and biological matter. The scientific literature is summarized, integrated, and critically analyzed with the help of authoritative reviews by recognized experts, international safety guidelines are also cited

Machine learning for molecular and materials science

Here we summarize recent progress in machine learning for the chemical sciences. We outline machine-learning techniques that are suitable for addressing research questions in this domain, as well as future directions for the field. We envisage a future in which the design, synthesis, characterization and application of molecules and materials is accelerated by artificial intelligence.</p

Problemy przyłączania farm wiatrowych do systemu elektroenergetycznego z wykorzystaniem kabli WN

This paper presents problems caused by connecting wind farms to a power system with high voltage cables. The author highlights possible problems with reactive power compensation, depending on the arrangement of the shunt reactor connection and settings of control systems for reactive power and voltage of the wind farm. The paper also discusses issues of increasing active power losses caused by a shunt reactor installation.Artykuł prezentuje problemy, jakie rodzi przyłączanie farm wiatrowych do systemu elektroenergetycznego za pomocą kabli wysokiego napięcia. Autor wskazuje możliwe problemy z kompensacją mocy biernej, w zależności od sposobu przyłączenia dławika kompensacyjnego i nastawień układów regulacji mocy biernej oraz napięcia farmy wiatrowej. Artykuł porusza też zagadnienia zwiększenia strat mocy czynnej powodowanych instalacją dławików kompensacyjnych

A new method of earth wires current calculation in HV transmission lines

Referat przedstawia nowatorską metodę obliczania wartości prądów płynących w przewodach odgromowych w czasie zwarć, pozwalającą na dobór przewodów odgromowych pod względem wytrzymałości cieplnej. Proponowana metoda charakteryzuje się większą dokładnością i większą uniwersalnością niż powszechnie stosowane metody, pozwalając tym samym na dobór przewodów odgromowych z mniejszym ryzykiem niepewności. Prezentowana metoda obliczeniowa pozwala również na ocenę ochrony przeciwporażeniowej linii, poprzez wyznaczenie wartości prądów płynących w uziomach słupów.The paper presents a new method to compute a phase-to-earth fault current distribution in overhead transmission line. The method is based on the tableau analysis of an unbalanced, multi-wire model of a transmission line. The proposed method allows the values of the currents in earth wires to be determined for each span of the line, as well as the current and voltage for every tower of the line. The advantage of this method over others is the possibility of carrying out calculations for any system configuration, regardless of its complexity. The method can be used for analysis of any type of transmission line (single circuit, double circuit and multi-circuit lines) with any number of earth wires. The calculation results may be used for complex designs of transmission line earthing systems, earth wire thermal rating selection, and the evaluation of shock hazards

Selected problems of connecting wind farms to the power system using high voltage underground cables

Referat prezentuje problemy jakie powstają przy przyłączaniu farm wiatrowych do systemu elektroenergetycznego za pomocą kabli wysokiego napięcia. Referat wskazuje możliwe problemy z kompensacją mocy biernej w zależności od sposobu przyłączenia dławika kompensacyjnego i nastawień układów napięcia farmy wiatrowej. Referat porusza też zagadnienia zwiększenia strat mocy czynnej powodowanych instalacją dławików kompensacyjnych.The paper presents the problems related to connecting wind farms to the power system by using high voltage underground cables. The paper indicates possible problems with reactive power compensation depending on the method of shunt reactor connection and setting wind farm reactive power and voltage control systems. The paper also shows issues of active power losses increasing caused by the installation of shunt reactors