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  • 1
    Electronic Resource
    Electronic Resource
    Interaction force detection in scanning probe microscopy: Methods and applications (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 1778-1798 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Fundamental aspects of interaction force detection and force microscopy are discussed. A formalism is developed for studying the dynamics of experimental setups in general terms. The analysis focuses on stability criteria and resonant properties of the force sensor. The latter are important for measuring interaction force gradients. Experimental techniques used for interaction force detection are examined in detail. Finally, experimental results are presented that demonstrate the potential of combining atomic scale interaction force detection with scanning tunneling microscopy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352348
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  • 2
    Electronic Resource
    Electronic Resource
    Nanoguitar: Oscillating string as force sensor (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 3576-3579 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A force sensor is presented that makes use of an oscillating string. In a conventional scanning force microscopy setup comprising a tip and a sample consisting of a flexible cantilever beam, a string is attached to the free end of the beam along its deflection axis. Changes of the tip–sample interaction force modify the string tension and hence the resonance frequency of transverse oscillations. These oscillations can have amplitudes of the order of microns without causing noticeable wavering of the cantilever beam. This kind of sensor is particularly suitable for applications that require a stiff sensor. A prototype was built using a carbon fiber 5 μm in diameter and 4 mm in length, oscillating at 4 kHz. A force resolution of 2.5 nN was achieved in vacuum for a response time of 1 ms and a sensor stiffness of 160 N/m. For a conventional beam deflection sensor of equal stiffness this corresponds to a deflection sensitivity of 0.015 nm. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145472
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrahigh vacuum compatible cooling and vibration isolation stage (1993)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3644-3646 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A scheme is described that resolves the problem of coupling sensitive equipment to a heat exchanger while retaining excellent isolation against vibrations in an ultrahigh vacuum environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144244
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  • 4
    Electronic Resource
    Electronic Resource
    Study of yielding mechanics in nanometer-sized Au contacts (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 637-639 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Yielding properties of Au point contacts of nanometer-scale dimensions have been studied using a scanning tunneling microscope supplemented by a force sensor for measuring tip–sample forces. The contacts are made by indenting the tip typically 10 nm into the substrate, whereby an adhesion neck is formed. Three consecutive deformation phases of the neck can be identified during retraction of the tip: (1) buildup of tensile stress, (2) incomplete fracture, and (3) quasicontinuous plastic flow. Finally the neck breaks when a maximum of three to four atoms are left in the contact. In the plastic flow regime, the conductance and thus the contact area shrink exponentially with elongation of the neck, suggesting that plastic deformation occurs locally within 5 to 6 atomic layers. The stress applied during plastic flow is initially of the order of 10 GPa and gradually increases to (approximately-equal-to) 20 GPa shortly before the neck breaks. Accounting for a surface force contribution, an intrinsic yield strength of the order of 5 to 8 GPa is obtained, which is more than one order of magnitude larger than the macroscopic yield strength of Au. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.116493
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  • 5
    Electronic Resource
    Electronic Resource
    Type-specific tumor patterns in the combined early and late cerebral scintigrams (1973)
    Springer
    Neuroradiology 6 (1973), S. 27-31 
    Details
    ISSN: 1432-1920
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Les auteurs ont étudié des scintigrammes cérébraux en série chez 196 malades porteurs de tumeurs vérifiées. En plus de l'analyse des caractéristiques observées au cours des radio-angiographies (stade I), l'intensité de l'activité de la tumeur au stade II et III (scintigramme précoce et tardif) fut comparée et classifiée. Les trois groupes d'intensité obtenus, c'est-à-dire II〉III, II=III et II〈III, furent ensuite analysés quant au type de la tumeur. Dans le groupe II〉III, 56% des tumeurs étaient des angiomes. Dans le groupe II=III, 45% des tumeurs étaient des méningiomes. Dans le groupe II〈III, 41% des tumeurs étaient des métastases et 47% des gliomes malins. Ces résultats encouragent à poursuivre l'utilisation de la combinaison des scintigrammes précoces et tardifs dans l'étude du diagnostic spécifique des tumeurs cérébrales. Il faut noter cependant que le comportement de la tumeur au stade I (radioangiographie) a également une signification diagnostique et est particulièrement utile dans la différenciation des tumeurs avec les lésions vasculaires.
    Abstract: Zusammenfassung Es wurden die Serien-Hirnszintigramme von 196 Patienten mit nachgewiesenen Hirntumoren untersucht. Dabei zeigte es sich, daß der Vergleich von den frühen Szintigrammen zu den späten Szintigrammen eine bessere Genauigkeit bei der Bestimmung der Art-Diagnose des Tumors ergab. Dies ist von besonderem Wert bei der Differenzierung eines Tumors zu einer vasculären Läsion.
    Notes: Summary The serial brain scintigrams in 196 patients with proven tumors have been reviewed. In addition to an analysis according to the characteristics observed during the CRAG (Stage I), the intensity of tumor activity in Stages II and III (early and late scintigrams) were compared and classified. The resulting three intensity groups, i.e. II〉III, II=III, and II〈III, were then further analyzed according to tumor type. Of those tumors with II〉III 56% were angiomas, of those tumors with II=III 45% were meningiomas, and of those with II〈III 43% were metastases and 43% malignant gliomas. These results encourage the further use of the combination of early and late scintigrams in the type-specific diagnosis of brain tumors. It must be stressed, however, that the tumor behavior in Stage I (CRAG) also has diagnostic significance and is particularly valuable in the differentiation of tumors from vascular lesions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00338855
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  • 6
    Electronic Resource
    Electronic Resource
    Type-specific tumor patterns in the cerebral radioangiography (CRAG): Results in 195 patients (1972)
    Springer
    Neuroradiology 3 (1972), S. 137-143 
    Details
    ISSN: 1432-1920
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'étude porte sur 195 cas de tumeurs vérifiées. La différenciation des anomalies observées en radio-angiographie fut évaluée quantitativement chez 47 malades, en appliquant la technique de «région intéressante» et les courbes activité-temps; qualitativement, l'étude est conduite chez 148 patients. Les résultats sont comparés au parenchyme normal. Les résultats correspondent à la vascularisation des tumeurs, ce qui peut être démontré, tant quantitativement que qualitativement, à l'aide d'images recueillies toutes les 4 sec pendant le temps de passage cérébral de l'embol 99 Tc.
    Abstract: Zusammenfassung Bei 47 Patienten wurde während der cerebralen Radio-Angiographie die unterschiedliche Aktivitätsanreicherung im Tumor untersucht (quantitative Messungen). Bei 148 Patienten erfolgten qualitative Differenz-Nachweise. Dabei wurden die cerebralen Veränderungen in 4 Gruppen eingeteilt (Angiome, Meningeome und Glioblastome, hochdifferenzierte und maligne Gliome, Metastasen).
    Notes: Summary The radioangiographic series of 195 patients with proven brain tumors have been reviewed. The differing behavior of these tumors during cerebral radioangiography (CRAG) was evaluated quantitatively in 47 patients, using the “region of interest” techniques and activity-time curves, and qualitatively in 148 patients. A “relative transport volume”, Q rel, the ratio of the curve integral over the abnormal region to that over normal parenchyma was introduced. This correlates with the tumor vascularity and can be calculated quantitatively, as well as demonstrated qualitatively by the pictures taken every 4 sec during the passage of the Tc-99m bolus through the brain. The tumors were divided into 4 groups: A) Angioma type (Q rel〉3) found in 65% of all the A-V angiomas. B) Meningioma/glioblastoma type (Q rel 1–3) with these tumors accounting for 81% of the tumors in this group. Approximately half of this 81% were meningiomas, diagnosed because of the typical delay in activity fall after its peak. Bone and malignant meningial processes fall into this range and follow the meningioma pattern qualitatively, but can be distinguished because of their superficial localization. C) Indifferent pattern (Q rel∼=1) was found with highly differentiated and malignant gliomas (46%) and metastases (40%). D) Metastatic type (Q rel〈1) with metastases found in 88% of this group. In addition, recurrent tumors often have changes in their radioangiographic pattern which result in Q rel values lower than those typical of their tumor type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00341496
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  • 7
    Electronic Resource
    Electronic Resource
    Functional radioangiographic studies of cerebral vascular haemodynamics (Preliminary report) (1972)
    Springer
    Neuroradiology 3 (1972), S. 144-149 
    Details
    ISSN: 1432-1920
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'angiographie cérébrale de routine (ler stade de la scintigraphie cérébrale) peut être complétée par un deuxième examen pratiqué après modifications mécaniques ou pharmaco-dynamiques de l'hémodynamique cérébral. Celleci peut être étudiée quantitativement à l'aide de courbes activité-temps et enregistrée dans des régions spécifiques. Dans le cas le plus simple, le flux de la redioactivité à travers le cercle de Willis peut être démontré après compression d'une carotide. L'hyperventialtion et l'augmentation de la pression sanguine ralentit le temps de circulation artério-veineuse chez les patiens normaux et chez la majorité de patients porteurs de tumeurs. A l'intérieur des tumeurs elles-mêmes, on note typiquement une relative diminution du temps circulatoire et en particulier, en cas d'augmentation de la pression sanguine, une augmentation considérable du volume relatif transporté. Chez plusieurs malades qui présentaient une augmentation du temps de circulation artério-veineuse, on observe une accélération paradoxale de la circulation. Nos résultats, en cas de tumeur et autres troubles cérébraux vasculaires, sont comparables à ceux obtenus avec d'autres méthodes de détermination du flux cérébral basé sur des radio-éléments diffusibles et sur des méthodes angiographiques. Toutefois, les techniques scintigraphiques ne nécessitent pas d'injections intra-artérielles et peuvent être appliquées de façon routinière, tant chez les malades hospitalisés que chez les malades ambulants, sans risque pour le patient.
    Abstract: Zusammenfassung Die routinemäßig durchgeführte cerebrale Radioangiographie kann durch eine zusätzliche Untersuchung nach mechanischer oder pharmakodynamischer Beeinflussung der cerebralen Hämodynamik vervollständigt werden. Es werden die Veränderungen beschrieben, die nach diesen mechanischen und pharmakodynamischen Tests auftreten.
    Notes: Summary Routine cerebral radioangiography (Stage I of the cerebral serial scintigraphy) can be supplemented with a second examination done after mechanical or pharmacodynamic change of the cerebral haemodynamics. These can be quantitatively evaluated by the use of activity-time curves taken over specific brain regions. In the simplest case, the flow of radioactivity through the circle of Willis can be demonstrated after compression of one carotid. Hyperventilation and increase of the blood pressure slow down the A-V circulation time in normal patients and in the majority of tumor patients. Within the tumors themselves there is typicallya relative decrease in the circulation time and, particularly with increased blood pressure, a considerable increase in the relative transport volume (Q rel). In several patients with primarily prolonged cerebral A-V circulation times, a paradoxical acceleration of the global circulation was observed. Our results in tumors and cerebrovascular diseases are comparable to those of other cerebral blood flow methods using diffusible redioactive substances and with contrast angiographic methods. However, the scintigraphic techniques do not require intra-arterial injections and can be used routinely in both hospitalized and ambulatory patients with no risk to the patient.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00341497
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  • 8
    Electronic Resource
    Electronic Resource
    L'activité des Offices régionaux et des Offices de réintégration (1960)
    Springer
    Sozial- und Präventivmedizin 5 (1960), S. 1-10 
    Details
    ISSN: 1420-911X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Invaliden werden in diesem Artikel in 3 Gruppen eingeteilt: a) Invalide, welche ihre Konkurrenzfähigkeit auf dem Arbeitsmarkt völlig oder größtenteils verloren haben (im ganzen 15 bis 20% der Invaliden) und welche in Spezialwerkstätten oder zu Hause arbeiten; b) Invalide, welche direkt in den Arbeitsprozeß wieder eingesetzt werden können (45 bis 50%), was dem Umstand zuzuschreiben ist, daß die meisten schweizerischen Unternehmen eine Arbeitsteilung und Rationalisierung eingeführt haben; c) Invalide, welche einer beruflichen Ausbildung fähig sind (35%) und damit wirtschaftlich besser gestellt werden. Diese berufliche Ausbildung kann in Rehabilitationszentren vorgenommen werden, welche mit der Wirtschaft engen Kontakt haben. Die Widereingliederung Behinderter in den Arbeitsprozeß besteht nicht nur in der Vermittlung bei den Arbeitgebern; es ist eine Gruppenarbeit, die qualifizierten Mitarbeitern anvertraut werden muß (Arzt, Psychotechnikern, Spezialisten der Rehabilitation und der Eingliederung usw.).
    Notes: Résumé Dans cet article, l'auteur classe les invalides en 3 catégories: a) les handicapés qui ont perdu totalement ou dans une large mesure leur capacité de concurrence sur le marché du travail (15 à 20% du total des invalides) et qui sont occupés dans des ateliers privilégiés ou à domicile; b) les handicapés pouvant être réintégrés directement dans l'économie (45 à 50%), grâce à la division et à la rationalisation du travail qui sont appliquées dans la plupart des entreprises suisses; c) les handicapés susceptibles de recevoir une formation professionnelle (35%), laquelle les valorise au point de vue économique. Cette formation professionnelle peut être organisée dans des centres de réadaptation branchés sur l'économie. Le reclassement professionnel des handicapés ne consiste pas simplement en démarches auprès des employeurs; c'est un travail d'équipe qui doit être confié à des collaborateurs qualifiés (médecin, psychotechniciens, spécialistes de la réadaptation et de l'intégration, etc.).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02031220
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