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61.
Igor Dmitruk Ivan Blonskiy Ihor Pavlov Oleg Yeshchenko Alexandr Alexeenko Andriy Dmytruk Petro Korenyuk Viktor Kadan 《Plasmonics (Norwell, Mass.)》2009,4(2):115-119
New method of experimental determination of local field enhancement at metal nanoparticles is suggested. It uses surface plasmon
as a probe. Alternating-sign shift of surface plasmon resonance in copper nanoparticles incorporated in silica matrix has
been observed under irradiation by intense femtosecond laser pulse. The red shift of plasmon observed during the action of
pump pulse is interpreted as a result of change of dielectric constant of silica matrix due to optical Kerr effect in electric
field of pump pulse enhanced in a vicinity of metal nanoparticles. The field enhancement factor is estimated from the value
of the observed red shift of plasmon resonance. 相似文献
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Autophagy is a process in which a eukaryotic (but not prokaryotic) cell destroys its own components through the lysosomal machinery. This tightly regulated process is essential for normal cell growth, development, and homeostasis, serving to maintain a balance between synthesis and degradation, resulting in the recycling of cellular products. Here we try to expand the concept of autophagy and define it as a general mechanism of regulation encompassing various levels of the biosphere. Interestingly, one of the consequences of such an approach is that we must presume an existence of the autophagic processes in the prokaryotic domain. 相似文献
64.
M. E. Mononen P. Julkunen J. T?yr?s J. S. Jurvelin I. Kiviranta R. K. Korhonen 《Biomechanics and modeling in mechanobiology》2011,10(3):357-369
Organization of the collagen network is known to be different in healthy, osteoarthritic and repaired cartilage. The aim of
the study was to investigate how the structure and properties of collagen network of cartilage modulate stresses in a knee
joint with osteoarthritis or cartilage repair. Magnetic resonance imaging (MRI) at 1.5 T was conducted for a knee joint of
a male subject. Articular cartilage and menisci in the knee joint were segmented, and a finite element mesh was constructed
based on the two-dimensional section in sagittal projection. Then, the knee joint stresses were simulated under impact loads
by implementing the structure and properties of healthy, osteoarthritic and repaired cartilage in the models. During the progression
of osteoarthritis, characterized especially by the progressive increase in the collagen fibrillation from the superficial
to the deeper layers, the stresses were reduced in the superficial zone of cartilage, while they were increased in and under
menisci. Increased fibril network stiffness of repair tissue with randomly organized collagen fibril network reduced the peak
stresses in the adjacent tissue and strains at the repair–adjacent cartilage interface. High collagen fibril strains were
indicative of stress concentration areas in osteoarthritic and repaired cartilage. The collagen network orientation and stiffness
controlled the stress distributions in healthy, osteoarthritic and repaired cartilage. The evaluation of articular cartilage
function using clinical MRI and biomechanical modeling could enable noninvasive estimation of osteoarthritis progression and
monitoring of cartilage repair. This study presents a step toward those goals. 相似文献
65.
Wolz R Julkunen V Koikkalainen J Niskanen E Zhang DP Rueckert D Soininen H Lötjönen J;Alzheimer's Disease Neuroimaging Initiative 《PloS one》2011,6(10):e25446
The role of structural brain magnetic resonance imaging (MRI) is becoming more and more emphasized in the early diagnostics of Alzheimer's disease (AD). This study aimed to assess the improvement in classification accuracy that can be achieved by combining features from different structural MRI analysis techniques. Automatically estimated MR features used are hippocampal volume, tensor-based morphometry, cortical thickness and a novel technique based on manifold learning. Baseline MRIs acquired from all 834 subjects (231 healthy controls (HC), 238 stable mild cognitive impairment (S-MCI), 167 MCI to AD progressors (P-MCI), 198 AD) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database were used for evaluation. We compared the classification accuracy achieved with linear discriminant analysis (LDA) and support vector machines (SVM). The best results achieved with individual features are 90% sensitivity and 84% specificity (HC/AD classification), 64%/66% (S-MCI/P-MCI) and 82%/76% (HC/P-MCI) with the LDA classifier. The combination of all features improved these results to 93% sensitivity and 85% specificity (HC/AD), 67%/69% (S-MCI/P-MCI) and 86%/82% (HC/P-MCI). Compared with previously published results in the ADNI database using individual MR-based features, the presented results show that a comprehensive analysis of MRI images combining multiple features improves classification accuracy and predictive power in detecting early AD. The most stable and reliable classification was achieved when combining all available features. 相似文献
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Mao X Gluck N Chen B Starokadomskyy P Li H Maine GN Burstein E 《The Journal of biological chemistry》2011,286(37):32355-32365
Cullin RING ligases (CRLs), the most prolific class of ubiquitin ligase enzymes, are multimeric complexes that regulate a wide range of cellular processes. CRL activity is regulated by CAND1 (Cullin-associated Nedd8-dissociated protein 1), an inhibitor that promotes the dissociation of substrate receptor components from the CRL. We demonstrate here that COMMD1 (copper metabolism MURR1 domain-containing 1), a factor previously found to promote ubiquitination of various substrates, regulates CRL activation by antagonizing CAND1 binding. We show that COMMD1 interacts with multiple Cullins, that the COMMD1-Cul2 complex cannot bind CAND1, and that, conversely, COMMD1 can actively displace CAND1 from CRLs. These findings highlight a novel mechanism of CRL activation and suggest that CRL regulation may underlie the pleiotropic activities of COMMD1. 相似文献
69.
Petro J. Zapata M. Ángeles Botella M. Teresa Pretel Maria Serrano 《Plant Growth Regulation》2007,53(2):97-106
The effect of salinity (100 mM NaCl) on ethylene metabolism in the early phase of vegetative development of several plant
species has been investigated. The effects of saline treatment on shoot and root growth, ranged in sensitivity with respect
to species: pepper (Capsicum annum L. cv Pairal) > tomato (Lycopersicon esculentum Mill. cv Malpica) > broccoli (Brassica oleraceae L. var. Italica Plenk. cv Marathon F1) ≅ lettuce (Lactuca sativa var. longifolia Lam. cv Inverna) ≅ melon (Cucumis melo L. cv Ruano F1, Roche type) > bean (Phaseolus vulgaris L. cv. Gator Green 15) ≅ spinach (Spinacia oleracea L. cv Boeing) > beetroot (Beta vulgaris L. var. crassa (Alef.) J. Helm. cv Detroit). After saline treatment, ethylene production increased 4.2-fold in pepper shoots. Significant
increases were also found in shoots of tomato, broccoli and bean. In contrast, salinity decreased shoot ethylene production
rate in melon, spinach, and beetroot. In roots, the general effect of salinity was a decrease in ethylene production, especially
in broccoli and bean, except in tomato root, in which a sharp increase in ethylene production occurred. In general, saline
treatment increased total ACC concentration in both shoot and root in most of the plant species examined, which was related
to plant sensitivity to salinity. For example, pepper shoot was the most sensitive to saline treatment, showing the highest
fresh weight inhibition and the highest increase in total ACC concentration (8.5-fold), while, beetroot was less affected
by salinity and showed no effect on total ACC concentration in response to saline treatment. 相似文献
70.
Hilde Van Esch Rita Colnaghi Kathleen Freson Petro Starokadomskyy Andreas Zankl Liesbeth Backx Iga Abramowicz Emily Outwin Luis Rohena Claire Faulkner Gary M. Leong Ruth A. Newbury-Ecob Rachel C. Challis Katrin Õunap Jacques Jaeken Eve Seuntjens Koen Devriendt Ezra Burstein Mark O’Driscoll 《American journal of human genetics》2019,104(5):957-967