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排序方式: 共有597条查询结果,搜索用时 0 毫秒
101.
DM Blischak SD Shah LJ Lombardino K Chiarella 《Disability and rehabilitation》2013,35(21-22):1295-1304
Purpose: To examine the effects of phoneme-grapheme correspondence and phonemic awareness instruction on the encoding abilities of three pre-reading children with severe speech impairment (SSI). Method: Using a single subject multiple baseline design across behaviours and participants, children received phoneme-grapheme awareness instruction followed by instruction in segmenting, manipulating, and encoding consonant-vowel-consonant (CVC) pseudowords. Results: Generalization occurred to encoding of novel CVC pseudo- and real words for two of the three participants. Conclusions: Results suggest that phoneme-grapheme correspondence and phonemic awareness instruction is effective in developing encoding skills in children with SSI. Findings are consistent with those for other at-risk children. 相似文献
102.
Integration of local inputs in visual cortex 总被引:1,自引:0,他引:1
In mammalian visual cortex, local connections are ubiquitous, extensively
linking adjacent neurons of all types. In this study, optical maps of
intrinsic signals and responses from single neurons were obtained from the
same region of cat visual cortex while the effectiveness of the local
cortical circuitry was altered by focally disinhibiting neurons within a
column of known orientation preference. Maps of intrinsic signals indicated
that local connections provide strong and functional subthreshold inputs to
neighboring columns of other orientation preferences, altering the observed
orientation preference to that of the disinhibited column. However,
measuring the suprathreshold response using single-cell recordings revealed
only mild changes of preferred orientation over the affected region.
Because strongly tuned subthreshold inputs from cortex only marginally
affect the tuning of a cortical cell's output, it is concluded that local
cortical inputs are integrated weakly compared to geniculate inputs. Such
circuitry potentially allows for the normalization of responses across a
wide range of input activity through local averaging.
相似文献
103.
104.
MR imaging of ductal carcinoma in situ 总被引:15,自引:0,他引:15
105.
Transfected leukocyte integrin CD11b/CD18 (Mac-1) mediates phorbol ester-activated, homotypic cell:cell adherence in the K562 cell line 总被引:1,自引:0,他引:1
Hickstein DD; Grunvald E; Shumaker G; Baker DM; Back AL; Embree LJ; Yee E; Gollahon KA 《Blood》1993,82(8):2537-2545
The CD11b/CD18 leukocyte integrin molecule mediates diverse neutrophil adherence-related functions, including cell:cell and cell:extracellular matrix attachments. To study the individual role of this leukocyte integrin in cell adherence in hematopoietic cells, we expressed the CD11b/CD18 complex on the surface of K562 cells, a cell line derived from an individual with chronic myelogenous leukemia in blast crisis. We used an amphotrophic retroviral vector designated LCD18SN, harboring the complete coding sequence for the CD18 subunit, to transfer the CD18 cDNA into K562 cells and select stable cell lines. The CD11b subunit in the expression plasmid pREP4 was transfected into these K562/CD18 cells by electroporation and stable cell clones were selected. These K562 cells possessed RNA and intracellular protein for each subunit, and they expressed the CD11b/CD18 heterodimer on the cell surface. When CD11b/CD18 expressing K562 cells were stimulated with phorbol myristate acetate (50 ng/mL) for 24 to 48 hours, these K562 cells formed dense cell:cell aggregates. This homotypic aggregation required both activation of the CD11b/CD18 complex and the induction of the counter- receptor for CD11b/CD18 on the conjugate cell. This cell line will (1) enable the structure-function relationships between cell activation and homotypic adherence to be assessed, (2) provide the opportunity to identify accessory molecules required for activation of the CD11b/CD18 complex, and (3) facilitate the identification of novel ligands for the CD11b/CD18 complex. 相似文献
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LJ Gould J Mushkudiani H Hou OY Grinberg S Grinberg HM Swartz 《Wound repair and regeneration》2004,12(2):A29-A29
Methods to reliably measure tissue oxygenation in situ are currently lacking. We have developed a vertically oriented, dorsal, bipedicle flap model that is easy to perform, reliably reproduces tissue ischemia, eliminates craniocaudal variation, and is amenable to studying therapeutic modalities. The effect of narrowing this flap on tissue oxygenation measured with Licox electrodes has previously been presented. In this study we utilize in situ EPR spectroscopy to demonstrate the oxygen gradient in the flap as a function of flap width and placement of a silicone sheet directly under the flap. The effect of wound healing over a 2 week period is demonstrated. Twenty four, 300 gm male Sprague‐Dawley rats underwent creation of the bipedicle flap according to the following groups: 2.5 cm flap with silicone, 2.0 cm flap without silicone, 2.0 cm flap with silicone. Each group of 6 animals was injected with EMS char at 2 cm intervals along the flap and one injection in the control, non‐ischemic tissue. A 4th group underwent 2.0 cm flaps with silicone and use of lithium phthalocyanin as the paramagnetic material. Wound measurements and EPR spectroscopy were performed on days 3, 7, 10 and 14. On day 14, after EPR measurements, the animals were sacrificed and their wounds excised. One flap and one control wound were preserved for histologic analysis, the other flap and control wounds were prepared for lactate measurements. EPR spectroscopy demonstrated a gradient of oxygen that was lowest in the center of the flap and greatest at either end. Changes in the oxygen gradient correlated with narrowing and placement of the intervening silicone sheet. This new technology has never been utilized in an animal model of impaired wound healing. Comparison of recently developed paramagnetic materials for optimal tissue oxygen and free radical measurements will be presented. 相似文献