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491.
Battistelli M Burattini S Pomini F Scavo M Caruso A Falcieri E 《Microscopy research and technique》2004,65(3):150-158
A morphological study was performed on 27 human placentas from normal gestations (Group 1) and compared with those from eight cases of intrauterine growth restriction (IUGR) (Group 2). Semithin section light microscopy, transmission, and scanning electron microscopy were carried out on trophoblastic terminal villi, carefully identified under the stereomicroscope. In growth retardation cases, villi appear longer, thinner, and less vascularized, compared to the normal condition. Fibrinoid, an extracellular material of hematic origin, frequently fills villar stroma. The density of apical microvilli appears considerably reduced and occasional microvilli-free areas are observed in growth retardation cases. Moreover, the underlying basal membrane appears significantly thicker than that of normal syncytiotrophoblast. Recently, particular attention has been paid to apoptosis as a possible cell deletion mechanism in growth restriction. In our study, a majority of typical apoptotic features appear indifferently in both IUGR and normal pregnancy. Our data hints that growth retardation might be correlated with a complex of structural changes, suggestive of maternofetal traffic downregulation, but further studies are required to understand the underlying functional mechanisms. 相似文献
492.
Gladis Madeline M.; Michela John L.; Walter Heather J.; Vaughan Roger D. 《Canadian Metallurgical Quarterly》1992,11(5):307
296 9th and 10th graders were asked to indicate their absolute and comparative risk of acquiring AIDS and to complete questionnaire items measuring AIDS-related behaviors and the constructs expected to influence risk judgments. Results indicate Ss used their behaviors as a basis for assessing personal risk in the sense that they perceived higher risk when their behavior was in fact riskier. However, this relation did not hold for those Ss classified as repressors on a repression-sensitization scale; repressors' perceptions of absolute (but not comparative) risk were negatively correlated with degree of behavioral risk. In a secondary analysis, perceived absolute risk emerged as a significant predictor of intention to change AIDS-risk behaviors. Data support a motivational interpretation of perceived invulnerability. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
493.
Studies using the selective cholinergic immunotoxin 192 IgG-saporin have demonstrated that lesions of the cholinergic input to the hippocampus from the medial septum/vertical limb of the diagonal band (MS/VDB) do not disrupt spatial learning in the water maze in young rats. However, age-related deficits in spatial learning correlate with the integrity of cholinergic neurons in the MS/VDB, suggesting that these neurons may be more crucial for spatial learning in aged rats. To investigate this hypothesis directly, we selectively lesioned these neurons in aged rats that demonstrated relatively intact spatial learning in an initial screening as well as in a comparison set of young rats. Intact and lesioned rats of both ages rapidly acquired a new place discrimination in a different spatial environment. These results indicate that the cholinergic input to the hippocampus is not differentially involved in spatial learning in aged rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
494.
NB De Cesare AL Bartorelli S Galli A Loaldi F Fabbiocchi P Sganzerla P Montorsi MD Guazzi 《Canadian Metallurgical Quarterly》1996,132(4):716-720
We evaluated acute and long-term clinical and angiographic results of elective Palmaz-Schatz coronary stent implantation for left anterior descending coronary artery (LAD) ostial stenosis in 23 consecutive patients. Eight patients had stable angina, 14 had unstable angina, and 1 had recent myocardial infarction. Sixteen patients had single-vessel, 5 had double-vessel, and 2 had triple-vessel disease. Clinical success without major complications (death, acute myocardial infarction, emergency coronary artery bypass grafting) was obtained in all cases and technical success in 20 cases (86.9%). After stenting, minimal lumen diameter increased from 1.05 +/- 0.45 mm to 2.89 +/- 0.52 mm (p < 0.001), and percent diameter stenosis decreased from 65.49% +/- 13.36% to 2.94% +/- 19.93% (p < 0.001). One case of subacute thrombosis and no major bleeding occurred. Twenty patients were followed-up for 6 months, during which no acute cardiac event (death, acute myocardial infarction) was observed. Eighteen patients were eligible for follow-up coronary angiography; restenosis (> or = 50% diameter stenosis) was observed in 4 (22.2%). Minimal lumen diameter was 1.77 +/- 0.55 mm, percent diameter stenosis was 39.66% +/- 17.62%, late loss was 1.01 +/- 0.69 mm, net gain was 0.79 +/- 0.55 mm, and loss index (late loss/acute gain) was 0.53 +/- 0.37. This study suggests that elective Palmaz-Schatz stent implantation may be a safe and successful treatment of LAD ostial lesions and provides a large increase in lumen diameter. 相似文献
495.
Boutillon E. Douillard C. Montorsi G. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2007,95(6):1201-1227
This tutorial paper gives an overview of the implementation aspects related to turbo decoders, where the term turbo generally refers to iterative decoders intended for parallel concatenated convolutional codes as well as for serial concatenated convolutional codes. We start by considering the general structure of iterative decoders and the main features of the soft-input soft-output algorithm that forms the heart of iterative decoders. Then, we show that very efficient parallel architectures are available for all types of turbo decoders allowing high-speed implementations. Other implementation aspects like quantization issues and stopping rules used in conjunction with buffering for increasing throughput are considered. Finally, we perform an evaluation of the complexities of the turbo decoders as a function of the main parameters of the code. 相似文献
496.
Sub-part correspondence by structural descriptors of 3D shapes 总被引:2,自引:0,他引:2
497.
Michela Semprebon Serena Vicari Haddock 《Journal of Housing and the Built Environment》2016,31(3):439-455
This article presents self-building projects and policy in Italy and discusses their potential to respond to housing needs in contemporary cities. It first analyzes a specific regional policy designed to promote access to housing for social groups excluded from the housing market and at the same time to foster integration between Italian and immigrant families. Secondly, it looks at the development and implementation of two self-building projects, one within the framework of the regional policy and one outside it. Our aim is to provide an assessment of the related policy and the practices in terms of institutional and social innovation. 相似文献
498.
Poccia N Fratini M Ricci A Campi G Barba L Vittorini-Orgeas A Bianconi G Aeppli G Bianconi A 《Nature materials》2011,10(10):733-736
The disposition of defects in metal oxides is a key attribute exploited for applications from fuel cells and catalysts to superconducting devices and memristors. The most typical defects are mobile excess oxygens and oxygen vacancies, which can be manipulated by a variety of thermal protocols as well as optical and d.c. electric fields. Here we report the X-ray writing of high-quality superconducting regions, derived from defect ordering, in the superoxygenated layered cuprate, La?CuO(4+y). Irradiation of a poor superconductor prepared by rapid thermal quenching results first in the growth of ordered regions, with an enhancement of superconductivity becoming visible only after a waiting time, as is characteristic of other systems such as ferroelectrics, where strain must be accommodated for order to become extended. However, in La?CuO(4+y), we are able to resolve all aspects of the growth of (oxygen) intercalant order, including an extraordinary excursion from low to high and back to low anisotropy of the ordered regions. We can also clearly associate the onset of high-quality superconductivity with defect ordering in two dimensions. Additional experiments with small beams demonstrate a photoresist-free, single-step strategy for writing functional materials. 相似文献
499.
500.
Schmidt M Zahn S Carella M Ohlenschläger O Görlach M Kothe E Weston J 《Chembiochem : a European journal of chemical biology》2008,9(13):2135-2146
The nickel complex of a synthetic nonapeptide (HCDLPCFVY-NH2) is capable of catalytically disproportionating O2(.-) and is thus a functional biomimetic for nickel superoxide dismutases. This represents a simplification as compared to a NiSOD "maquette" that is based on a dodecapeptide that was recently reported [Inorg. Chem. 2006, 45, 2358]. The 3D solution structure reveals that the first six residues form a stable macrocyclic structure with a preformed binding site for Ni(II). Proline 5 exhibits a trans peptide linkage in the biomimetic and a cis conformation in NiSOD enzymes. DFT calculations reveal the source of this preference. Mechanistic consequences for the mode of action (identity of the fifth ligand) are discussed. The SOD activity is compared to enzymatic systems, and selected modifications allowed the biomimetic to be reduced to a functional minimal motif of only six amino acids (ACAAPC-NH2). 相似文献