Energy transfer and compatibility analysis of PVK/MEH-PPV blends processed via electrospraying and electrospinning

Solution polymer blends of a high molecular weight and a low molecular weight poly(9-vinyl carbazole) PVK with poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), at a fixed blend ratio of 95.5:0.5, were processed via electrospraying and electrospinning. SEM studies revealed that electrosprayed particles were produced when low molecular weight PVK was used, while electrospun fibers were successfully obtained from solutions containing high molecular weight PVK, over a concentration range of 4–10% (w/v). From the absorption spectra of the neat polymers it was determined that Urbach energy E_u increase and optical band gap E_g decreases due to the physical defects along the main chain introduced by these electrostatic processing methods. Photoluminescence spectroscopy revealed a particular applied voltage, which depends on concentration and molecular weight, where aggregation of PVK levels off. Luminescence quenching of MEH-PPV is also observed to increase with applied voltage consistent with possible energy transfer from shorter conjugation length segments to nearby longer conjugated segments. The ratio of the intensity of the excitation spectra of the PVK (donor, both PVK_L or PVK_H) and the MEH-PPV (acceptor), I_D/I_A, exhibited minima at this particular voltage and then levels off, indicating not only maximum interpenetration and thus compatibility of both polymers but also maximum energy transfer. Hence, we demonstrate that compatibility and energy transfer can be optimized varying concentration and applied voltage during both electrospraying and electrospinning processes.     

Dodecyl acetate,a second pheromone component of the cabbage looper moth,Trichoplusia ni

Dodecyl acetate was identified as a second component of the sex pheromone ofTrichoplusia ni (Hübner). Dodecyl acetate comprised 9.6% by weight of the total pheromone [(Z)-7-dodecenyl acetate plus dodecyl acetate] extracted from glands and 7.3% by weight of the total pheromone evaporated from the surfaces of glands. Dodecyl acetate appears to function as a short-range pheromone component. Evaporation at female release rates of a 1090 mixture of dodecyl acetate and (Z)-7-dodecenyl acetate in the field caused a significantly greater percentage of males to land on the pheromone source, increased significantly the time they spent on the source, but decreased significantly the time they spent searching for the source when within 50 cm, as compared to (Z)-7-dodecenyl acetate alone.Lepidoptera: Noctuidae.     

基于含硫单体的可降解聚酯的表征与性能

以硫代二丙酸和间苯二酚二(2-羟乙基)醚为主要原料,Sb2 O3为催化剂,通过熔融缩聚法合成了聚(硫代二丙酸-间苯二酚二(2-羟乙基)醚)酯.采用FT-IR、1 H NMR,对聚酯的结构进行了表征;采用GPC、DSC、TGA测试其相对分子质量和热性能;并采用自然掩埋法,对其在土壤中的降解性能进行了考察.结果表明:该新型含硫聚酯数均相对分子质量和重均相对分子质量分别为12634 g/mol和19708 g/mol、热分解5％温度为351.7℃,热分解50％温度为401.5℃,熔点为99.12℃,ΔHm为90.12 J/g,且在自然土壤环境下经过24个月的降解,聚酯P的失重率达到9.3％,具有较好的降解性能.     

Early predictors of biliteracy development in children in French immersion: A 4-year longitudinal study.

English language predictors of English and French reading development were investigated in a group of 140 children who were enrolled in French immersion programs. Children were first tested in kindergarten, and their reading achievement was tested yearly in both English and French from Grades 1 to 3, with word-level and passage-level measures that assessed accuracy as well as fluency. Hierarchical linear modeling was used to examine which English variables predicted Grade 3 outcomes and growth rates in English and French, and to determine the set of predictors that accounted for the most variance in outcomes and growth rates in English and French reading. The variables that predicted English reading development were consistent with studies of monolingual English children, even though participants were concurrently learning to read in French. Our findings provide evidence that at least some of the skills that play a role in learning to read are general cognitive and linguistic skills that transfer across languages. Phonological awareness, letter-sound knowledge, rapid automatized naming, and grammatical ability in English were able to predict reading ability in French. In contrast, English receptive vocabulary was a language-specific predictor. These findings demonstrate that first-language measures can be useful in the early identification of children at risk for difficulty in learning to read in a second language. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Crossover: The role of morphological awareness in French immersion children's reading.

Achieving biliteracy is a remarkable accomplishment, and it is important to understand the range of factors that permit its successful realization. The authors investigated a factor known to affect reading in monolingual children that has received little attention in the second-language literature: morphological awareness. The researchers tracked the relationships between performance on past tense analogy tasks (the measure of morphological awareness) and reading of English and French in a group of 58 French immersion children across Grades 1-3. Early measures of English morphological awareness were significantly related to both English and French reading, after controlling for several variables. In contrast, early measures of French morphological awareness were significantly related to French reading only. Later measures of morphological awareness in French were significantly related to English and French reading. These relationships persisted even after controlling for several variables. Results of this study suggest that morphological awareness can be applied to reading across orthographies and that this relationship changes as children build their language and literacy skills. These findings are discussed in light of current theories of second-language reading acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Factors related to English reading performance in children with Chinese as a first language: More evidence of cross-language transfer of phonological processing.

Parallel measures of phonological, syntactic, and orthographic processing skill and reading were administered in English and in Chinese to 65 children whose 1st language (L1) was Cantonese and whose 2nd language (L2) was English. Phonological skill was correlated across L1 and L2. Phonological skill in both L1 and L2 was correlated with L2 reading and contributed a unique variance to L2 reading, even though the children's L1 was not written in an alphabetic orthography, whereas the 2nd language had an alphabetic orthography. This research adds to a growing body of evidence for cross-language transfer of phonological processing in L2 learning of English-as-a-Second-Language students. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Organoids: An Emerging Tool to Study Aging Signature across Human Tissues. Modeling Aging with Patient-Derived Organoids

The biology of aging is focused on the identification of novel pathways that regulate the underlying processes of aging to develop interventions aimed at delaying the onset and progression of chronic diseases to extend lifespan. However, the research on the aging field has been conducted mainly in animal models, yeast, Caenorhabditis elegans, and cell cultures. Thus, it is unclear to what extent this knowledge is transferable to humans since they might not reflect the complexity of aging in people. An organoid culture is an in vitro 3D cell-culture technology that reproduces the physiological and cellular composition of the tissues and/or organs. This technology is being used in the cancer field to predict the response of a patient-derived tumor to a certain drug or treatment serving as patient stratification and drug-guidance approaches. Modeling aging with patient-derived organoids has a tremendous potential as a preclinical model tool to discover new biomarkers of aging, to predict adverse outcomes during aging, and to design personalized approaches for the prevention and treatment of aging-related diseases and geriatric syndromes. This could represent a novel approach to study chronological and/or biological aging, paving the way to personalized interventions targeting the biology of aging.