November 11,1992 was the thir-ty fifth anniversary of China A-cademy of Launch Vehicle Technol-ogy(CALT),which grows out ofthe First Branch of the Fifth Acade-my under the Ministry of *** Xuesen was itsfirst president...
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November 11,1992 was the thir-ty fifth anniversary of China A-cademy of Launch Vehicle Technol-ogy(CALT),which grows out ofthe First Branch of the Fifth Acade-my under the Ministry of *** Xuesen was itsfirst president. Since its establishment in 1957,under the guidance of the principleof relying on our own efforts,striking for external assistance andmaking good use of science andtechnology achieved by the devel-oped countries,CALT has been de-
Current angioplasty devices are limited by arterial wall dissection and perforation, and by early recurrence from inadequate debulking of lesions. This study evaluated intravascular ultrasound (IVUS) as guidance for c...
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Current angioplasty devices are limited by arterial wall dissection and perforation, and by early recurrence from inadequate debulking of lesions. This study evaluated intravascular ultrasound (IVUS) as guidance for concentric laser recanalization of arterial occlusions. Twelve, 2-4-cm-long canine iliac artery occlusions were treated at 2 weeks (organizing thrombus) to 12 weeks (firm fibrous lesions) using a Holmium:YAG laser (2,100 nm wavelength) in free running mode, FRM, (250-mu-sec pulse, 5 Hz), n = 9;and Q-switched mode, QSM (200 ns pulse, 6 Hz), n = 3. A 200-mu-m (n = 2) or 600-mu-m (n = 10) optic fiber was centered in the artery coaxial to a 5Fr rotating A scan IVUS probe. The fiber was positioned in the center of the artery distal to the lesion and slowly advanced through the obstruction. In 8 occlusions the same fiber was used as a guidewire for passage of either a 1.6-mm-(n=2) and/or 3.0-mm (n=6) diameter multifiber catheter (19 x 100 and 19 x 200-mu-m fibers, respectively) using FRM energy to further debulk the lesion. In all cases, IVUS guidance enabled concentric initial recanalization of occlusions, although 3 vessel perforations resulted from fiber deviation off the center of the lumen at a distance of 2 to 4 cm from the IVUS imaging element. Both QSM and FRM modes ablated tissue, with FRM modes producing more tissue fragmentation and thermal effect. IVUS images accurately diagnosed the location of lesions compared to angioscopic views and pathologic analysis of the specimens. This study suggests that IVUS guided laser energy may enable initial concentric recanalization of arterial occlusions if adequate tissue removal can be accomplished to provide continuous IVUS imaging as the recanalization proceeds.
In vivo, intracellular recordings of mammalian brain stem motoneurones, followed by peroxidase staining and tridimensional reconstruction, suggest that the shape of the dendritic tree plays an important role in the pr...
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In vivo, intracellular recordings of mammalian brain stem motoneurones, followed by peroxidase staining and tridimensional reconstruction, suggest that the shape of the dendritic tree plays an important role in the processing of neural information. To test this hypothesis attempts were made to guide, in culture, the growth of neuritic branches of neurones dissociated from the hypoglossal nucleus of rat brain stem. This was performed using topographical and adhesive microstructures which were designed to control the shape of the neuritic tree. guidance of the neuritic process can be observed with small grooves engraved on quartz and plastic substrates, and simple shapes with few processes and bifurcations on each neurite could be obtained using adhesive microstructures. These procedures, which allow the shape of a neurone to be controlled, are very promising in the study, by means of classical electrophysiological methods as well as optical recordings, of the involvement of dendritic architecture in the processing of neural information.
There are two guiding modes of the Hubble Space Telescope used for the acquisition of astronomical data by one of its six scientific instruments. The nominally more precise one is called Fine Lock and the other is kno...
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The outgrowth of corticospinal tract axons in rat spinal cord primarily occurs during the first postnatal week. Axons originating from a group of layer V pyramidal cell bodies situated in the anterior part of the cere...
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The outgrowth of corticospinal tract axons in rat spinal cord primarily occurs during the first postnatal week. Axons originating from a group of layer V pyramidal cell bodies situated in the anterior part of the cerebral sensorimotor cortex project mainly to the cervical gray matter (Joosten et al., Dev. Brain Res., 36 (1987) 121-130). By co-culturing explants of the anterior part of the sensorimotor cortex and of cervical spinal gray matter in 3-D collagen gels, a target-specific directional growth of cortical axons towards the cervical spinal gray explant could be demonstrated. After retrograde filling with the fluorescent tracer 1,1-dioctadecyl-3,3,3',3'-tetramethyl indocarbocyanine perchlorate (DiI), in vivo as well as in vitro, most of the DiI-labelled cortical neurons were located in layer V of the cortical explant, and were characterized by a pyramidal shape. These data suggest that the cervical spinal gray matter target area becomes innervated by corticospinal axons through the release of a diffusible chemotropic factor.
Sensory neurons of Hirudo medicinalis were cultivated on patterns of extracellular matrix (ECM) protein which were prepared by UV irradiation using copper grid masks. The relation of the patterns and of the outgrowth ...
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Sensory neurons of Hirudo medicinalis were cultivated on patterns of extracellular matrix (ECM) protein which were prepared by UV irradiation using copper grid masks. The relation of the patterns and of the outgrowth of neurites was observed by scanning electronmicroscopy after gold decoration. The neurites were guided by narrow (10-mu-M) lanes of ECM protein. Branching of neurites was induced by branched lanes. Bent neurites were pulled off bent lanes at some distance behind the growth cone such that their length was reduced. Regularly spaced sites of adhesion became visible which remained connected to the neurites by extended filaments.
Notes for Contributors The following notes have been compiled for the guidance of authors who are preparing papers for submission to Chinese Geographical Science. Submission of papers Papers may be sent for aditorial ...
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Notes for Contributors The following notes have been compiled for the guidance of authors who are preparing papers for submission to Chinese Geographical Science. Submission of papers Papers may be sent for aditorial consideration to the Editorial Depqrtement. Only the editors has the responsibility for deciding whether a paper is to be accepted, re-
This writer argues that guid ance counselors should have the authority to place at-risk learners in nonconventional educational programs to ensure that those learners who, for social, educational, and emotional reason...
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This writer argues that guid ance counselors should have the authority to place at-risk learners in nonconventional educational programs to ensure that those learners who, for social, educational, and emotional reasons are not benefiting fully from the traditional educational pro cess will acquire the basic skills they will need to func tion productively in society.
The static magnetic field of a magnetic resonance (MR) imaging system was used as a component of an electromagnetic transducer for generating acoustic pressure waves. To permit limited focusing, the transducer was con...
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The static magnetic field of a magnetic resonance (MR) imaging system was used as a component of an electromagnetic transducer for generating acoustic pressure waves. To permit limited focusing, the transducer was constructed from a conductive thin plate shaped like a section of a sphere. The plate was placed within the static field of the MR unit (B0 = 1.5 T). and current pulses with a rise time of 73 nsec and amplitude of 1.0 kA were applied to it. Hydrophonic recording demonstrated a shock wave with a peak pressure of 4.8 MPa at the approximated focal point. MR guidance of lithotripsy would be particularly useful to limit undesirable soft-tissue damage. It is also suggested that the integration of an acoustic pressure wave generator with MR imaging and control provides a novel technology for the treatment of solid soft-tissue tumors.
*** the construction during the last fourty years andespecially under the guidance of the“Reform and opening”policy,the power generation equipment manufacturing industry of Chinahas achieved tremendous development i...
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*** the construction during the last fourty years andespecially under the guidance of the“Reform and opening”policy,the power generation equipment manufacturing industry of Chinahas achieved tremendous development in the 1980’***
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