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1.
Jaques Lahaye  Pierre Ehrburger 《Fuel》1985,64(9):1187-1191
Penetration of molten pitch into a coke bed is correlated with thermodynamic properties of pitch and of pitch-coke interfaces, as well as with the rheology of the liquid. A review of the possible relation between the above properties and the molecular properties of the pitch is presented.  相似文献   
2.
Hydrogels, three‐dimensional hydrophilic polymer network structures, can absorb many times their dry weight in water. PolyHIPEs are highly porous polymers synthesized within high internal phase emulsions (HIPEs). Here, the water uptakes in novel hydrogel polyHIPE copolymers of hydroxyethyl methacrylate (HEMA, a non‐ionic monomer) and methacrylic acid (MAA, an ionic monomer) were investigated. The PHEMA‐based polyHIPE had a density of 0.14 g cm?3, void diameters of 50–100 µm and a void‐dominated Fickian water uptake of around 10.4 g g?1. The polyHIPE density increased, and the porous structure became less polyHIPE‐like, with increasing MAA content, reflecting a reduction in the stability of the HIPE. The water uptake increased with increasing pH for all the copolymers and the water absorption mechanism changed from Fickian at pH 2 to anomalous, dominantly case II, at pH 10. The maximum uptake of 18.2 g g?1 at pH 10, for a HEMA to MAA mass ratio of 1/1, was ascribed to hydrogel‐swelling‐driven void expansion. The hydrogel's absorptive and responsive properties were amplified by the polyHIPE's porous structure. These results demonstrate that the compositions of hydrogel polyHIPE copolymers can be designed to enhance their water uptake. © 2015 Society of Chemical Industry  相似文献   
3.
The beneficial effects of direct predation by zoophytophagous biological control agents (BCAs), such as the mirid bug Nesidiocoris tenuis, are well-known. However, the benefits of zoophytophagous BCAs’ relation with host plants, via induction of plant defensive responses, have not been investigated until recently. To date, only the females of certain zoophytophagous BCAs have been demonstrated to induce defensive plant responses in tomato plants. The aim of this work was to determine whether nymphs, adult females, and adult males of N. tenuis are able to induce defense responses in tomato plants. Compared to undamaged tomato plants (i.e., not exposed to the mirid), plants on which young or mature nymphs, or adult males or females of N. tenuis fed and developed were less attractive to the whitefly Bemisia tabaci, but were more attractive to the parasitoid Encarsia formosa. Female-exposed plants were more repellent to B. tabaci and more attractive to E. formosa than were male-exposed plants. When comparing young- and mature-nymph-exposed plants, the same level of repellence was obtained for B. tabaci, but mature-nymph-exposed plants were more attractive to E. formosa. The repellent effect is attributed to the signaling pathway of abscisic acid, which is upregulated in N. tenuis-exposed plants, whereas the parasitoid attraction was attributed to the activation of the jasmonic acid signaling pathway. Our results demonstrate that all motile stages of N. tenuis can trigger defensive responses in tomato plants, although these responses may be slightly different depending on the stage considered.  相似文献   
4.
Gitis V  Adin A  Nasser A  Gun J  Lev O 《Water research》2002,36(17):4227-4234
A new method for the study of pathogen transport in porous media is presented. The method is based on conjugation of fluorescent dyes to target bacteriophages and application of the modified bacteriophages for tracer studies. We demonstrate that the relevant transport determining properties of Rhodamine and several fluorescein-labeled phages are practically identical to those of the native bacteriophages. The advantages of the proposed method relative to direct enumeration of bacteriophages by plaque forming unit method, turbidity, fluorescent microspheres, and other alternative tracers are discussed. Notable advantages include simple quantitation by optical methods, unbiased signals even when virus aggregates are formed, and the ability to decouple inactivation kinetics from transport phenomena. Additionally, the signal reflects the removal and transport of the studied microorganism and not a surrogate.  相似文献   
5.
Organically modified silica sol-mediated capillary electrophoresis   总被引:1,自引:0,他引:1  
Neiman B  Grushka E  Gun J  Lev O 《Analytical chemistry》2002,74(14):3484-3491
We describe in this paper the use of ormosil (organically modified silica) sols as additives to the run buffer for selectivity manipulations between solutes in capillary electrophoresis. CE systems that contain sol additives in the run buffer can be thought of as pseudocapillary electrochromatography. Three sols based on different types of silanes were studied. Methyltrimethoxysilane (MTMOS)-based sol was found to improve selectivities between various aromatic acids. Aminopropyltrimethoxysilane (APS) sol interacts differently with structural isomers of aromatic acids than does MTMOS. At low pH with APS sol in the run buffer, neutral solutes can be separated, as well. The separation of the neutral solutes seems to be facilitated by the formation of hydrogen bonds between the solutes and the APS sol. APS and N-[3-(trimethoxysilyl)propyl]-ethylenediamine (EDAS) affect the separation of the same compounds differently, thus indicating that even small changes of the functional groups of the sol have pronounced effect on the interactions between the sols and the solutes.  相似文献   
6.
Transposition of the great arteries is a complex cardiac malformation with poor prognosis without surgical correction. Since the introduction of surgical procedures such as the intra-auricular reorientation of the venous return (Mustard procedure), an increasing number of patients may reach adulthood and experience pregnancy. Because long-term complications after the Mustard operation include systemic heart failure, arrhythmias, venous return stenosis and pulmonary edema, hemodynamic changes during pregnancy and delivery may potentially engender life-threatening complications in these patients. We report the case of a 24-year-old primigravida who underwent a Mustard procedure at the age of 2 years for transposition of the great vessels, and who carried out a full-term pregnancy. The pregnancy was uneventful until the 34th week, when the woman developed signs of moderate right ventricular failure and frequent episodes of accelerated junctional rhythm. Digitalisation improved symptoms and elicited return to normal sinus rhythm. The patient delivered at term by elective cesarean section, under close hemodynamic monitoring.  相似文献   
7.
Analyzed behavior during videotaped family interaction in an unstructured situation (interpreted as interpersonally stressful). 20 families contained a disturbed child (aggressive, socially withdrawn, or distractible); 10 were normal control families. Repeated judgments were made on evaluative, directing, and activity dimensions. Analyses of covariance (covariate: amount of talking) showed significant differences between fathers but not mothers or children. Fathers of normal children were evaluatively neutral and nondirecting (suggesting low attempts to control others) and untalkative (suggesting social independence). Fathers of disturbed children showed controlling and/or dependent behavior: (a) fathers of distractible children were evaluatively extreme and talkative; (b) fathers of withdrawn children were neutral, nondirecting, and talkative; and (c) fathers of aggressive children were negatively extreme, directing, and untalkative. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
8.
9.
The performance characteristics and applications of hybrid multichannel amplitude modulation vestigal sideband (AM-VSB)/M-quadrature amplitude modulation (QAM) video lightwave transmission systems operating at either 1310 or 1550 nm are reviewed. These systems can transport up to 80 AM-VSB video channels and more than 30 64/256-QAM digital video channels over a standard single-mode fiber (SMF) using a single laser transmitter. Five main transmission impairment mechanisms for these systems are reviewed as follows: (a) clipping-induced impulse noise, (b) bursty nonlinear distortions, (c) multiple optical reflections, (d) stimulated Brillouin scattering, and (e) self-phase modulation. For AM-QAM video lightwave trunking applications, the in-line erbium-doped fiber amplifier (EDFA) selection is discussed using a frequency-domain simulation model. Such lightwave trunking systems can provide an AM carrier-to-noise ratio (CNR) greater than 50 dB with composite second order (CSO) and composite-triple-beat (CTB) distortions less than -65 dBc, and nearly error-free transmission (BER⩽10-9) for the 64-QAM channels with signal-to-noise ratio (SNR) of 30-dB or better. Comparison between 64-QAM and 256-QAM video channel transmission and the effect of the QAM channels on the AM-VSB channels are also presented. The implications of these results and others in hybrid multichannel AM-QAM video lightwave trunking systems are discussed  相似文献   
10.
Translational recruitment of maternal mRNAs is an essential process in early metazoan development. To identify genes required for this regulatory pathway, we have examined a collection of Drosophila female-sterile mutants for defects in translation of maternal mRNAs. This strategy has revealed that maternal-effect mutations in the cortex and grauzone genes impair translational activation and cytoplasmic polyadenylation of bicoid and Toll mRNAs. Cortex embryos contain a bicoid mRNA indistinguishable in amount, localization, and structure from that in wild-type embryos. However, the bicoid mRNA in cortex embryos contains a shorter than normal polyadenosine (poly(A)) tail. Injection of polyadenylated bicoid mRNA into cortex embryos allows translation demonstrating that insufficient polyadenylation prevents endogenous bicoid mRNA translation. In contrast nanos mRNA, which is activated by a poly(A)-independent mechanism, is translated in cortex embryos, indicating that the block in maternal mRNA activation is specific to a class of mRNAs. Cortex embryos are fertilized, but arrest at the onset of embryogenesis. Characterization of grauzone mutations indicates that the phenotype of these embryos is similar to cortex. These results identify a fundamental pathway that serves a vital role in the initiation of development.  相似文献   
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