Transesterification of dimethyl teraphalate with ethylene glycol catalyzed by amberlyst 15.

Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.A.Sc.)--University of Windsor (Canada), 1978

RESPONDING TO PRODUCT IN THE COMPOSING PROCESS

The traditional method of responding to ESL students' written composition tends to stress linguistic accuracy, requiring the correction, usually by the teacher, of discrete grammatical items at the sentence level. Studies by In their study, Robb, Ross and Shortreed (1986) found that direct methods of feedback did not tend to produce results commensurate with the amount of effort required of the instructor to draw students' attention to surface errors, and that highly detailed feedback on sentence-level errors was not worth the instructors' time and effort. Although it appears that there is no consensus on how teachers should best react to student writing, or at what stage in the composing process they should provide feedback on students' mechanical errors, Krashen (1984) recommended delaying corrective feedback on errors until the final stage of editing. Krashen's suggestion reflects a growing understanding among researchers and teachers that writing involves producing a text that evolves over time. This has concomitantly resulted in a new and fresh approach for responding to student writing, a two-phase response, with the initial focus on content, delaying feedback on mechanical errors until "the work-in-progress" is fully shaped and becomes a finished product. This staggered and discriminate feedback fosters a more realistic and positive attitude towards rewriting, which is thus separated into two distinct and sequential tasks, viz. revision for content/meaning and editing for form/mechanics. Not only is revision differentiated from editing, but it is also prioritized over editing, thus reflecting and reinforcing that language, be it spoken or written, is primarily a communicative tool; written composition is organized communication. How is this response to writing more realistic? In responding first to the message/content, rather than to the form, teachers are showing cognizance of research which reveals that rewriting is an important part of the IN THE CLASSROOM/EN CLASSE 6

Leadership for Learning Improvement in Urban Schools

Examines urban school leaders' efforts to improve the quality of teaching and learning by supporting progress for diverse students, sharing leadership work, and aligning resources. Analyzes school environments and coordination of various leadership roles

A Checkpoint-Related Function of the MCM Replicative Helicase Is Required to Avert Accumulation of RNA:DNA Hybrids during S-phase and Ensuing DSBs during G2/M

The Mcm2-7 complex is the catalytic core of the eukaryotic replicative helicase. Here, we identify a new role for this complex in maintaining genome integrity. Using both genetic and cytological approaches, we find that a specific mcm allele (mcm2DENQ) causes elevated genome instability that correlates with the appearance of numerous DNA-damage associated foci of γH2AX and Rad52. We further find that the triggering events for this genome instability are elevated levels of RNA:DNA hybrids and an altered DNA topological state, as over-expression of either RNaseH (an enzyme specific for degradation of RNA in RNA:DNA hybrids) or Topoisomerase 1 (an enzyme that relieves DNA supercoiling) can suppress the mcm2DENQ DNA-damage phenotype. Moreover, the observed DNA damage has several additional unusual properties, in that DNA damage foci appear only after S-phase, in G2/M, and are dependent upon progression into metaphase. In addition, we show that the resultant DNA damage is not due to spontaneous S-phase fork collapse. In total, these unusual mcm2DENQ phenotypes are markedly similar to those of a special previously-studied allele of the checkpoint sensor kinase ATR/MEC1, suggesting a possible regulatory interplay between Mcm2-7 and ATR during unchallenged growth. As RNA:DNA hybrids primarily result from transcription perturbations, we suggest that surveillance-mediated modulation of the Mcm2-7 activity plays an important role in preventing catastrophic conflicts between replication forks and transcription complexes. Possible relationships among these effects and the recently discovered role of Mcm2-7 in the DNA replication checkpoint induced by HU treatment are discussed

The impacts of value, disconfirmation and satisfaction on loyalty: Evidence from international higher education setting

Relationships with international students can be beneficial to higher education in terms of financial and human resources. For this reason, establishing and maintaining such relationships are usually pre-eminent concerns. In this study, we extended the application of the disconfirmation expectation model by incorporating components from subjective task value to predict the loyalty of international students toward their host countries. On a sample of 410 Vietnamese students enrolled in establishments of higher education in over 15 countries across the globe, we employed structural equation model to construct the conceptual model. Our empirical findings revealed that while the roles of satisfaction and disconfirmation are still important as direct and indirect antecedents of international student loyalty, its most powerful predictors are the three components of subjective task value: attainment, utility and intrinsic. These insights result in a number of implications for actors on the higher ducation scene, such as heads of institutions and policy makers

Transcriptome of oil palm (Elaeis guineensis Jacq.) roots treated with Ganoderma boninense

Basal stem rot (BSR) is the most devastating disease of oil palm. In this study, we examined the transcriptional responses of oil palm roots treated with a causal agent of BSR, Ganoderma boninense using a cDNA microarray approach. A total of 61 from 3,748 transcripts examined were found to be significantly up- or down-regulated in oil palm roots infected with G. boninense at 3 and 6 weeks post inoculation compared to those from uninfected roots. The differentially expressed genes identified in the artificially infected oil palm roots included genes encoding isoflavone reductase, Em protein H2, SPX domain-containing protein 1, pathogenesis-related protein 1, vicilin-like antimicrobial peptide. The gene expression of isoflavone reductase, which is involved in the production of phytoalexin and three related genes in the phenylpropanoid biosynthetic pathway was also profiled in the treated oil palms using real-time quantitative reverse transcription PCR. This information has contributed to our understanding of the defense mechanisms of oil palm in response to G. boninense, the future development of molecular markers for marker assisted breeding and screening of oil palms that are tolerant to G. boninense

Interleukin-1 mediates Alzheimer and Lewy body pathologies

BACKGROUND: Clinical and neuropathological overlap between Alzheimer's (AD) and Parkinson's disease (PD) is now well recognized. Such cases of concurrent AD and Lewy body disease (AD/LBD) show neuropathological changes that include Lewy bodies (α-synuclein aggregates), neuritic amyloid plaques, and neurofibrillary tangles (hyperphosphorylated tau aggregates). The co-occurrence of these clinical and neuropathological changes suggests shared pathogenic mechanisms in these diseases, previously assumed to be distinct. Glial activation, with overexpression of interleukin-1 (IL-1) and other proinflammatory cytokines, has been increasingly implicated in the pathogenesis of both AD and PD. METHODS: Rat primary cultures of microglia and cortical neurons were cultured either separately or as mixed cultures. Microglia or cocultures were treated with a secreted fragment (sAPPα) of the β-amyloid precursor protein (βAPP). Neurons were treated with IL-1β or conditioned medium from sAPPα-activated microglia, with or without IL-1 receptor antagonist. Slow-release pellets containing either IL-1β or bovine serum albumin (control) were implanted in cortex of rats, and mRNA for various neuropathological markers was analyzed by RT-PCR. Many of the same markers were assessed in tissue sections from human cases of AD/LBD. RESULTS: Activation of microglia with sAPPα resulted in a dose-dependent increase in secreted IL-1β. Cortical neurons treated with IL-1β showed a dose-dependent increase in sAPPα release, an effect that was enhanced in the presence of microglia. IL-1β also elevated the levels of α-synuclein, activated MAPK-p38, and phosphorylated tau; a concomitant decrease in levels of synaptophysin occurred. Delivery of IL-1β by slow-release pellets elevated mRNAs encoding α-synuclein, βAPP, tau, and MAPK-p38 compared to controls. Finally, human cases of AD/LBD showed colocalization of IL-1-expressing microglia with neurons that simultaneously overexpressed βAPP and contained both Lewy bodies and neurofibrillary tangles. CONCLUSION: Our findings suggest that IL-1 drives production of substrates necessary for formation of the major neuropathological changes characteristic of AD/LBD

Apolipoprotein E expression is elevated by interleukin 1 and other interleukin 1-induced factors

<p>Abstract</p> <p>Background</p> <p>We have previously outlined functional interactions, including feedback cycles, between several of the gene products implicated in the pathogenesis of Alzheimer's disease. A number of Alzheimer-related stressors induce neuronal expression of apolipoprotein E (ApoE), β-amyloid precursor protein (βAPP), and fragments of the latter such as amyloid β-peptide (Aβ) and secreted APP (sAPP). These stressors include interleukin-1 (IL-1)-mediated neuroinflammation and glutamate-mediated excitotoxicity. Such circumstances are especially powerful when they transpire in the context of an <it>APOE </it>ε4 allele.</p> <p>Methods</p> <p>Semi-quantitative immunofluorescence imaging was used to analyze rat brains implanted with IL-1β slow-release pellets, sham pellets, or no pellets. Primary neuronal or NT2 cell cultures were treated with IL-1β, glutamate, Aβ, or sAPP; relative levels of ApoE mRNA and protein were measured by RT-PCR, qRT-PCR, and western immunoblot analysis. Cultures were also treated with inhibitors of multi-lineage kinases--in particular MAPK-p38 (SB203580), ERK (U0126), or JNK (SP600125)--prior to exposure of cultures to IL-1β, Aβ, sAPP, or glutamate.</p> <p>Results</p> <p>Immunofluorescence of tissue sections from pellet-implanted rats showed that IL-1β induces expression of βAPP, IL-1α, and ApoE; the latter was confirmed by western blot analysis. These protein changes were mirrored by increases in their mRNAs, as well as in those encoding IL-1β, IL-1β-converting enzyme (ICE), and tumor necrosis factor (TNF). IL-1β also increased ApoE expression in neuronal cultures. It stimulated release of sAPP and glutamate in these cultures too, and both of these agents--as well as Aβ--stimulated ApoE expression themselves, suggesting that they may contribute to the effect of IL-1β on ApoE levels. Inhibitors of MAPK-p38, ERK, and JNK inhibited ApoE induction by all these agents except glutamate, which was sensitive only to inhibitors of ERK and JNK.</p> <p>Conclusion</p> <p>Conditions of glial activation and hyperexcitation can elevate proinflammatory cytokines, ApoE, glutamate, βAPP, and its secreted fragments. Because each of these factors promotes glial activation and neuronal hyperexcitation, these relationships have the potential to sustain self-propagating neurodegenerative cycles that could culminate in a progressive neurodegenerative disorder such as Alzheimer's disease.</p