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31.
Inside Back Cover: Designed Enclosure Enables Guest Binding Within the 4200 Å3 Cavity of a Self‐Assembled Cube (Angew. Chem. Int. Ed. 19/2015) 下载免费PDF全文
32.
Shiran Shahar Pnina Hillman Rachel Lubart Debby Ickowicz Haim Breitbart 《Photochemistry and photobiology》2014,90(5):1077-1083
To acquire fertilization competence, spermatozoa must undergo several biochemical and motility changes in the female reproductive tract, collectively called capacitation. Actin polymerization and the development of hyperactivated motility (HAM) are part of the capacitation process. In a recent study, we showed that irradiation of human sperm with visible light stimulates HAM through a mechanism involving reactive‐oxygen‐species (ROS), Ca2+ influx, protein kinases A (PKA), and sarcoma protein kinase (Src). Here, we showed that this effect of light on HAM is mediated by ROS‐dependent activation of the epidermal growth factor receptor (EGFR). Interestingly, ROS‐mediated HAM even when the EGFR was activated by EGF, the physiological ligand of EGFR. Light irradiation stimulated ROS‐dependent actin polymerization, and this effect was abrogated by PBP10, a peptide which activates the actin‐severing protein, gelsolin, and causes actin‐depolymerization in human sperm. Light‐stimulated tyrosine phosphorylation of Src‐dependent gelsolin, resulting in enhanced HAM. Thus, light irradiation stimulates HAM through a mechanism involving Src‐mediated actin polymerization. Light‐stimulated HAM and in vitro‐fertilization (IVF) rate in mouse sperm, and these effects were mediated by ROS and EGFR. In conclusion, we show here that irradiation of sperm with visible light, enhances their fertilization capacity via a mechanism requiring ROS, EGFR and HAM. 相似文献
33.
Haim?KaplanEmail author Edgar?Ramos Micha?Sharir 《Discrete and Computational Geometry》2011,45(1):3-33
In approximate halfspace range counting, one is given a set P of n points in ℝ
d
, and an ε>0, and the goal is to preprocess P into a data structure which can answer efficiently queries of the form: Given a halfspace h, compute an estimate N such that (1−ε)|P∩h|≤N≤(1+ε)|P∩h|. 相似文献
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We study the problem of whether a coalgebra that generates its category of left (right) comodules is left (right) quasi-coFrobenius
or not. We prove it does not hold in general, by giving a method of constructing counterexamples. This gives a negative answer
to a question stated in Nastasescu et al. (Algebr Represent Theory 11(2):179–190, 2008). We also prove it is true for monomial pointed coalgebras and we characterize the quivers Q such that
\mathbbkQ\mathbb{k}Q admits a monomial subcoalgebra that is left (right) quasi-coFrobenius. 相似文献
36.
Haim Taitelbaum 《Journal of statistical physics》1995,78(3-4):1183-1184
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Detailed 1H NMR studies of ms tetraphenylchlorins (H2TPC), new amino- and hydroxypyrroline substituted ms tetraphenylchlorins and ms tetraphenylisobacteriochlorins (H2TPisoB) are presented and discussed. The results obtained are consistent with the general aspects of the ring current models as applied to the parent porphyrins. According to proton chemical shifts a gradual reduction in the magnitude of the ring current is observed in the order ms tetraphenylporphyrin (H2TPP) > H2TPC> ms tetraphenylbacteriochlorin (H2TPB) > H2TPisoB. The 1H NMR spectra show chemical non-equivalence of the pyrroline ring protons due to adjacent substituents, and effects of steric constraints on the aminoalkyl substituents due to the close vicinity to the meso phenyl rings. The non-equivalence of the methylene protons of the pyrroline ring produces geminal coupling between the two methylene protons and vicinal coupling with the adjacent pyrroline proton, more pronounced in H2TPC? OH and in . Restricted configuration of the methylene groups in the ethyl groups of H2TPC? C(H)(CH3)N(CH2CH3)2 produces observable geminal coupling between the methylene protons. 1H NMR reveals the difference between two types of meso phenyls in the chlorins, and three types of meso phenyls in isobacteriochlorins, as reflected in the chemical shifts of the o-phenyl protons. 相似文献
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