Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: During development motoneurons depend on target contact for their survival. Following injury to the sciatic nerve in neonatal rats, a large proportion of motoneurons die. However, the same injury inflicted at 5 days of age results in no loss of motoneurons. This critical period of postnatal development coincides with the time during which there is a significant increase in the release of transmitter from the nerve terminals at the neuromuscular junction. We have proposed that the role of the target muscle cell during this period is to induce this up-regulation of transmitter release from motor nerve terminals. It has been shown that stretch-induced increase in transmitter release from frog motor nerve terminals is accomplished via an integrin-dependent mechanism. In this study we examined the role of integrins at the rat neuromuscular junction in motoneuron survival. We found that blocking integrin binding at the developing neuromuscular junction delayed the increase in choline acetyltransferase activity that normally takes place during the early postnatal period, and resulted in motoneuron death. Furthermore, the maturation of those motoneurons that survived was delayed so they remained susceptible to subsequent nerve injury. These results support the possibility that integrins, by their involvement in modulating transmitter release, can influence motoneuron survival.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Anaesthesia 50 (1995), S. 0 
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In characterising the forces exerted during laryngoscopy it is accepted that the significant force component is that which is parallel to the axis of the laryngoscope handle. This paper describes a new method of evaluating the forces exerted at laryngoscopy. A laryngoscope handle has been redesigned, incorporating a force-displacement transducer on the handle at the end opposite to where the blade is attached. The device is designed specifically to sense the axial component of force. The blade attachment block has been detached from the sleeve and connected to a steel shaft which forms the new battery compartment. This allows the axial force exerted at the blade during laryngoscopy to be transmitted along this shaft to the sensing transducer. Linear ball bearings have been introduced between the new shaft and the handle sleeve (outer casing). The rolling friction has been reduced to less than 0.1 % by diamond-lapping the precision ground surface -hardened rod to produce a mirror finish. Thus, the force transmitted to the transducer is essentially constant regardless of where the load is applied along the blade. The output from the system is directly downloaded to a laptop computer and the data analysed almost instantaneously to determine the duration of laryngoscopy, the peak forces applied, the mean force with its standard deviation and graphic display of the data. Provision has been made for data entry checks, recording patient details and study data, and creating a data base for the storage and retrieval of the study details.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 55 (1999), S. 576-578 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The growth of modulation-doped InAs/(Al,Ga)Sb quantum wells on GaAs substrates employing molecular beam epitaxy requires care in the nucleation and the use of buffer layers to achieve high quality material. Despite a 7% lattice mismatch between the substrate and the active layers, fully relaxed epitaxial growth can be accomplished, and quantum wells with electron sheet concentrations of 7×1012 cm−2 having low-temperature mobilities as high as 300 000 cm2/V s have been routinely fabricated recently in our laboratory. In the present work the combination of atomic force microscopy and van der Pauw measurements is used to investigate and explain the strong influence of the buffer layers on the morphology in the quantum well that is shown to be responsible for the great differences in the observed low-temperature mobilities. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 117 (1995), S. 12344-12345 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Discrete event dynamic systems 6 (1996), S. 241-273 
    ISSN: 1573-7594
    Keywords: hierarchical control ; control structures ; observers ; hierarchical consistency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract An abstract hierarchical control theory is developed for discrete-event systems, based on the concepts of control structures and observers. Control structure is an abstract generalization of the family of controllable sublanguages in the Ramadge-Wonham framework. We establish a general version of Zhong's hierarchical consistency by first achieving control consistency — preservation of control structures through the aggregation mapping in a two-level hierarchy. For a refinement of hierarchical consistency with preservation of nonblocking, the concept of observer is introduced via congruences on nondeterministic transition structures.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Discrete event dynamic systems 6 (1996), S. 275-306 
    ISSN: 1573-7594
    Keywords: timed discrete-event systems ; time control structures ; hierarchical consistency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract An abstract hierarchical control theory is developed for a class of timed discrete-event systems (TDES) within the discrete-event control architectural framework proposed earlier by the authors. For this development, a control theory for TDES is introduced in the spirit of a prior theory of Brandin. A notion of time control structures is introduced, and on its basis a general property of hierarchical consistency is achieved by establishing control consistency — namely preservation of time control structures through the aggregation mapping in a two-level hierarchy.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Histopathology 12 (1988), S. 0 
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A male infant was diagnosed as having diabetes mellitus 1d after birth and died on the third day. Histological examination of the pancreas showed small and inconspicuous islets of Langerhans that were completely devoid of insulin-secreting cells. There was no evidence of insulitis.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We have proposed an equation for estimating the real-time mixed venous blood concentration (MVBC) of isoflurane in cardiac anaesthesia. However, information related to the application of our method to sevoflurane is lacking. We studied 12 patients undergoing cardiac surgery and anaesthetised with sevoflurane. At different time points, pulmonary arterial blood samples were collected for gas chromatography-mass spectrometry (GC-MS) to determine the real mixed venous concentrations of sevoflurane. The inspired and expired concentrations of sevoflurane, measured by a gas monitor, were used for the MVBC calculations. Using Bland-Altman analyses, we found that the calculated MVBCs accurately represent the actual concentrations of sevoflurane in pulmonary arterial blood, as shown by a near-zero percentage bias with a 0.14% precision between the two concentrations. The results demonstrated that our equation could be a useful method for estimating the pulmonary blood concentration of sevoflurane.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Anaesthesia 37 (1982), S. 0 
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The roles of the autonomic nervous system and cardiac output on hypoxic pulmonary vasoconstriction were studied in 15 mongrel dogs anaesthetised with intravenous pentoharbitone (30 mg/kg) and the lungs mechanically ventilated to maintain normal arterial blood gases. After a hypoxic challenge in Group I (n =6) and Group II (n =3) animals, autonomic denervation was achieved by total spinal block with tetracaine (20 mg) injected into the cisterna magna. Group I animals received a large volume of intravenous fluid (80 ml/kg normal saline) before the block while Group II animals were given minimum fluid. When Group I animals were exposed to 10% inspired oxygen, mean pulmonary arterial pressure increased by 88 and by 72% before and after the block, respectively. The cardiac output increased by 27% with hypoxia before the block while it did not change significantly with hypoxia after the block. The pulmonary vascular resistance increased by 65 and by 152% with hypoxia before and after the block. Group II animals were also exposed to 10% inspired oxygen. They showed a similar response to Group I animals before the block. However, after the block irreversible hypotension developed with hypoxia. In Group III animals (n =6), the same anaesthesia and hypoxic challenge protocol was used. Immediately after measurements at 10 minutes of hypoxia, the inferior vena cava was constricted to reduce the cardiac output to the control level and another set of measurements were made. The cardiac output increased by 30% with hypoxia and then was reduced to the control level with vena caval constriction. The mean pulmonary arterial pressure increased by 125% with hypoxia and then it decreased slightly with the inferior vena cava constriction. The pulmonary vascular resistance increased by 95% with hypoxia and then it further increased by 28% with the vena caval constriction. These results suggest that sympathectomy accentuates rather than attenuates the hypoxic pulmonary vasoconstriction and that an increase in cardiac output counteracts hypoxic pulmonary vasoconstriction. The results also suggest that adequate intravascular volume and oxygenation are extremely important for maintaining homeostasis when reflex sympathetic stimulation to the cardiovascular system has been eliminated.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...