Search Results - (Author, Cooperation:S. Erne)

2015-04-11

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2018-04-20

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Geosciences

Computer Science

Medicine

Natural Sciences in General

Physics

Physics

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

We developed a system for localizing orthogonal triplets of small magnetic dipoles with an array of magnetometers. These triplets can be used to measure, in quasi-real time, the position of an object. This system is particularly useful when used with superconducting biomagnetic multichannel detectors. We present here a complete numerical simulation of the system performances and the first experimental tests with a biomagnetic detector (an array of 37 superconducting magnetometers). This system can be operated at frequencies outside the range of interest for biomagnetic measurements (that is typically 10−2–103 Hz). It features an accuracy of ±0.3 cm driving the triplet at a field intensity ≈10−12 T. The speed of the algorithm allows for quasi-real-time operation (t ∼ 10−1 s).

Electronic Resource

0160-2527

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Psychology

Law

Electronic Resource

0392-6737

Biomagnetism (including magnetocardiography)

Springer Online Journal Archives 1860-2000

Physics

Riassunto L'attività del sistema di His-Purkinje è stata misurata magneticamente usando un magnetometro SQUID nella camera schermata magneticamente di Berlino (BMSR) e usando in aggiunta filtraggio (banda passante da 0.5 Hz a 300 Hz) e tecniche di mediazione. La camera riduce il livello di rumore di fondo a meno di 4 $$4{{fT} \mathord{\left/ {\vphantom {{fT} {\sqrt {Hz} }}} \right. \kern-\nulldelimiterspace} {\sqrt {Hz} }}$$ nella regione a spettro bianco. All'interno dell'intervalloPR è stata osservata una struttura a rampa, la cui pendenza cambia segno attraversando la linea mediana del cuore. In aggiunta, sono stati registrati segnali ben definiti approssimativemente 40 ms prima dell'inizio dell'attivazione ventricolare.

Резюме йзмеряется активность НР системы у человека с помощью SQUID магнетометра в Берлинской магнитно экранированной комнате, используя фильтртрацию полосы пропускания (ширина полосы от 0.5 Гц до 300 Гц) и усреднение. Берлинская магнитно экранированная комната уменьшает уровень фонового шума до величины $$4{{fT} \mathord{\left/ {\vphantom {{fT} {\sqrt {Hz} }}} \right. \kern-\nulldelimiterspace} {\sqrt {Hz} }}$$ в области белого шума. ВнутриPR интервла наблюдается диаграмма с уклоном, причем величина ыклона меняется при пересечении медианной линии сердца. Кроме того, ориблизительно за 40 мс до наступления активности желудочка регистрируются определенные сигналы.

Summary The activity of the His-Purkinje system (HPS) in man has been measured magnetically with a SQUID magnetometer in the Berlin magnetically shielded room (BMSR) by using in addition band pass filtering (band width 0.5 Hz to 300 Hz) and averaging. The BMSR reduces the background noise level to less than $$4{{fT} \mathord{\left/ {\vphantom {{fT} {\sqrt {Hz} }}} \right. \kern-\nulldelimiterspace} {\sqrt {Hz} }}$$ in the region of white noise. Within thePR interval a ramp pattern was observed, changing its slope when crossing the median line of the heart. In addition, definite signals were recorded approximately 40 ms before the onset of ventricular activation.

Electronic Resource

0392-6737

Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets

Springer Online Journal Archives 1860-2000

Physics

Riassunto Il magnetocardiogramma ad alta risoluzione è stato registrato mediante magnetometri superconduttori in 12 volontari sani utilizzando la camera schermata di Berlino per ridurre il livello di rumore elettromagnetico. La morfologia del trattoPR magnetico è caratterizzata dalle «rampe» in precedenza osservate, sulle quali s’inseriscono segnali. A volte la forma d’onda appare complessa.

Summary ThePR interval of magnetocardiograms has been measured with a SQUID sensor in the Berlin magnetically shielded room. In addition to previously reported ramps with isolated superimposed signals in several cases a structured morphology has been found.

Electronic Resource

0392-6737

Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets

Springer Online Journal Archives 1860-2000

Physics

Riassunto La motivazione fondamentale per lo studio dei fenomeni elettrofisiologici cardiaci tramite il metodo biomagnetico è dovuta al fatto che questa tecnica offre un’alta risoluzione spaziale e sembra fornire informazioni complementari rispetto alle sole registrazioni elettriche. Fino ad oggi l’interesse degli studiosi si è concentrato su due differenti fenomeni cardiaci: 1) lo studio dell’attività del sistema di conduzione atrioventricolare e 2) lo studio della depolarizzazione ventricolare anormalmente ritardata (late potentials). L’interesse clinico per lo studio non invasivo del sistema di His-Purkinje (HPS) è ben noto. Registrazioni cliniche non invasive di late potentials sono particolarmente desiderabili in quanto possono essere preziosi indicatori di rischio di morte improvvisa. In questo lavoro si presenta una rassegna sullo stato delle ricerche in entrambi i campi d’indagine.

Summary The fundamental motivation for investigating cardiac electrophysiological phenomena by means of the biomagnetic method has been that this technique should have added spatial resolution and provided complementary information as opposed to electric recordings only. So far the interest of experimentalists has been concentrated on two different kinds of cardiac phenomena: 1) the study of the activity of the cardiac conduction system and 2) of abnormally delayed ventricular depolarization (late potentials). The clinical interest for the noninvasive investigation of the His-Purkinje system (HPS) is well known. Noninvasive clinical recording of late potentials is particularly desirable as they seem to be precious markers for risk of sudden death. A review of the state of research in both fields is presented in this paper.

Electronic Resource

0392-6737

Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets

Springer Online Journal Archives 1860-2000

Physics

Riassunto Il magnetocardiogramma ad alta risoluzione, registrato in 22 pazienti affetti da pregresso infarto del miocardio, ha permesso di rilevare in 3 casi la presenza di segnali di ampiezza tra 0.4 e 3 pT temporalmente correlati a depolarizzazioni tardive elettriche. Si discutono de differenze tra segnali magnetici ed elettrici e il loro possibile significato fisiopatologico.

Summary High-resolution magnetocardiograms of patients with recent myocardial infarction have been recorded. In three cases, signals have been found in theST segment that are time correlated with simultaneously recorded late electric potentials.

Electronic Resource

0392-6737

Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets

Springer Online Journal Archives 1860-2000

Physics

Riassunto Si presentano i risultati preliminari ottenuti costruendo mediante computer mappe di distribuzione di campo magnetico sulla base di registrazioni ad alta risoluzione effettuate con magnetometro superconduttore. La procedura è stata applicata per esaminare i MCG di 16 pazienti affetti da pregresso infarto del miocardio. Sulla base di questa elaborazione è stato possibile dividere i pazienti in due classi, una delle quali contiene tutti i pazienti con depolarizzazioni tardive.

Summary A possible clinical application of a high-resolution magnetic isofield contour mapping technique in cardiography is discussed. Preliminary results are presented in applying this technique to patients with recent myocardial infarction. The patients could be divided into two classes; one of them contains patients with electrical late potentials as a subclass.

Electronic Resource

1573-6792

Biomagnetism ; Magnetoencephalography

Springer Online Journal Archives 1860-2000

Medicine

Electronic Resource