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1.
Reading Motivation: Multidimensional and Indeterminate. 总被引:1,自引:0,他引:1
The Motivations for Reading Questionnaire (MRQ) contains 54 items that are posited to tap 11 dimensions of reading motivation. The structural validity of the MRQ was investigated with 2 samples: (a) 328 students in Grades 3-5 from 2 suburban mid-Atlantic elementary schools and (b) 735 students in Grades 3-5 in 2 suburban southwestern elementary schools. With confirmatory factor analyses (CFAs), the theoretical 11-factor structure did not adequately fit the data in either sample. Subsequently, exploratory factor analyses found 8 factors for each sample with 6 factors defined by only 3 or 4 common items. However, a double CFA cross-validation found an inadequate fit for both samples. Given these results, the authors suggest that the MRQ be revised. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
2.
Antisense oligonucleotide inhibition of hepatitis C virus gene expression in transformed hepatocytes
R Hanecak V Brown-Driver MC Fox RF Azad S Furusako C Nozaki C Ford H Sasmor KP Anderson 《Canadian Metallurgical Quarterly》1996,70(8):5203-5212
Genetic and biochemical studies have provided convincing evidence that the 5' noncoding region (5' NCR) of hepatitis C virus (HCV) is highly conserved among viral isolates worldwide and that translation of HCV is directed by an internal ribosome entry site (IRES) located within the 5' NCR. We have investigated inhibition of HCV gene expression using antisense oligonucleotides complementary to the 5' NCR, translation initiation codon, and core protein coding sequences. Oligonucleotides were evaluated for activity after treatment of a human hepatocyte cell line expressing the HCV 5' NCR, core protein coding sequences, and the majority of the envelope gene (E1). More than 50 oligonucleotides were evaluated for inhibition of HCV RNA and protein expression. Two oligonucleotides, ISIS 6095, targeted to a stem-loop structure within the 5' NCR known to be important for IRES function, and ISIS 6547, targeted to sequences spanning the AUG used for initiation of HCV polyprotein translation, were found to be the most effective at inhibiting HCV gene expression. ISIS 6095 and 6547 caused concentration-dependent reductions in HCV RNA and protein levels, with 50% inhibitory concentrations of 0.1 to 0.2 microM. Reduction of RNA levels, and subsequently protein levels, by these phosphorothioate oligonucleotides was consistent with RNase H cleavage of RNA at the site of oligonucleotide hybridization. Chemically modified HCV antisense phosphodiester oligonucleotides were designed and evaluated for inhibition of core protein expression to identify oligonucleotides and HCV target sequences that do not require RNase H activity to inhibit expression. A uniformly modified 2'-methoxyethoxy phosphodiester antisense oligonucleotide complementary to the initiator AUG reduced HCV core protein levels as effectively as phosphorothioate oligonucleotide ISIS 6095 but without reducing HCV RNA levels. Results of our studies show that HCV gene expression is reduced by antisense oligonucleotides and demonstrate that it is feasible to design antisense oligonucleotide inhibitors of translation that do not require RNase H activation. The data demonstrate that chemically modified antisense oligonucleotides can be used as tools to identify important regulatory sequences and/or structures important for efficient translation of HCV. 相似文献
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RE O'Carroll A Moffoot KP Ebmeier C Murray GM Goodwin 《Canadian Metallurgical Quarterly》1993,23(2):341-347
Eighteen patients suffering from Alcoholic Korsakoff's Syndrome participated in a placebo-controlled double-blind cross-over trial of clonidine 0.3 mg b.d. for two weeks versus matched placebo for two weeks. A detailed neuropsychological assessment was carried out at the end of each treatment phase and staff ratings of behaviour were also obtained. Clonidine treatment resulted in no significant improvement over placebo on any of the cognitive measures employed. The results contradict previous smaller studies which had suggested that chronic treatment with clonidine had a memory-enhancing effect in Korsakoff's syndrome. 相似文献
5.
In rhodopsin, the 11-cis-retinal chromophore forms a complex with Lys296 of opsin via a protonated Schiff base. Absorption of light initiates the activation of rhodopsin by cis/trans photoisomerization of retinal. Thermal relaxation through different intermediates leads into the metarhodopsin states which bind and activate transducin (Gt) and rhodopsin kinase (RK). all-trans-Retinal also recombines with opsin independent of light, forming activating species of the receptor. In this study, we examined the mechanism by which all-trans-retinal activates opsin. To exclude other amines except active site Lys296 from formation of Schiff bases, we reductively methylated rhodopsin (PM-rhodopsin), which we then bleached to generate PM-opsin. Using spectroscopic methods and a Gt activation assay, we found that all-trans-retinal interacted with PM-opsin, producing a noncovalent complex that activated Gt. The residual nucleotide exchange in Gt catalyzed by opsin was approximately 1/250 lower relative to that of photoactivated rhodopsin (pH 8.0, 23 degrees C). Addition of equimolar all-trans-retinal led to an occupancy of one-tenth of the putative retinal binding site(s) of opsin and enhanced the Gt activation rate 2-fold. When the concentration of all-trans-retinal was increased to saturation, the Gt activation rate of the opsin/all-trans-retinal complex was approximately 1/33 lower compared to that of photoactivated rhodopsin. We conclude that all-trans-retinal can form a noncovalent complex with opsin that activates Gt by different mechanisms than photolyzed rhodopsin. 相似文献
6.
KP Fennelly 《Canadian Metallurgical Quarterly》1997,18(1):1-17
The present study investigated the simultaneous occurrence of emergent stimulus-response relations (functional equivalence) and stimulus-stimulus relations (stimulus equivalence). After being pretrained and tested on two symbolic match-to-sample tasks (X1-Y1, X2-Y2), 20 4- and 5-year-old children were trained to emit specified responses to pairs of stimuli (A1-R1, B1-R1, A2-R2, B2-R2) in one setting (original training) and to emit other responses to one member of each pair (A1-R3, A2-R4) in another setting (reassignment training). Of the 18 children who responded correctly on all trained tasks, 15 emitted the novel responses also in the presence of the nonreassigned stimuli (B1-R3, B2-R4). Eleven of these children also matched same-class stimuli with one another (A1-B1, A2-B2, and vice versa). Additional tests with four of these children documented the formation of conditional response-stimulus relations (R3-B1, R4-B2) in all four children, and of conditional response-response relations (R1-R3, R2-R4, and vice versa) in two of them. Children who did not show stimulus control transfer also failed to match same-class stimuli with one another. Present findings, together with those obtained in animal research, suggest that functional equivalence can imply but does not require stimulus equivalence. 相似文献
7.
Characterization of the epidermal growth factor receptor in pig oviduct and endometrium 总被引:1,自引:0,他引:1
K Wollenhaupt U Tiemann R Einspanier F Schneider W Kanitz KP Brüssow 《Canadian Metallurgical Quarterly》1997,111(2):173-181
Two different plaque variants of Japanese encephalitis virus were selected from a wild-type Taiwanese isolate using Vero cells. One variant was found to exhibit small plaque morphology with retarded virus replication kinetics in Vero cells, and was demonstrated to be resistant to monoclonal antibody (mAb) E3.3 neutralization. The other variant showed large plaque morphology, was sensitive to mAb E3.3 neutralization, and manifested reduced virulence in mice on both intracranial and intraperitoneal inoculations. These two variants propagated in Vero cells retained high levels of infectivity but had relatively low HA titers as compared with the parent strain. The envelope sequences of these two variants showed four amino acid differences at residues E-85 (Glu/Arg), E-306 (Glu/Gly), E-331 (Ser/Arg), and E-387 (Met/Arg). Our results indicated the neutralizing epitope of Japanese encephalitis virus did not overlap with virus virulence determinant. 相似文献
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9.
FE Nargang KP Künkele A Mayer RG Ritzel W Neupert R Lill 《Canadian Metallurgical Quarterly》1995,14(6):1099-1108
MOM22 is a component of the protein import complex of the mitochondrial outer membrane of Neurospora crassa. Using the newly developed procedure of 'sheltered disruption', we created a heterokaryotic strain harboring two nuclei, one with a null allele of the mom-22 gene and the other with a wild-type allele. Homokaryons bearing the mom-22 disruption could not be isolated, suggesting that mom-22 is an essential gene. The mutant nucleus can be forced to predominate in the heterokaryon through the use of specific nutritional and inhibitor resistance markers. Cultivation of the heterokaryon under conditions favoring the mutant nucleus resulted in selective depletion of MOM22. MOM22-depleted cells did not grow and contained mitochondria with an altered morphology and protein composition. Protein import into isolated, MOM22-depleted mitochondria was abolished for most precursor proteins destined for all subcompartments. In contrast, precursors of MOM19, MOM22 and MOM72 became inserted normally into the outer membrane, defining a novel MOM22-independent import pathway which remained intact in mutant mitochondria. Furthermore, the specific binding of the ADP/ATP carrier to the outer membrane was unaffected, but subsequent transport across the outer membrane did not occur. Our data show that MOM22 is an essential component of Neurospora cells specifically required for the biogenesis of mitochondria. 相似文献
10.
HJ Berger KP van Spaendonck MW Horstink EL Buytenhuijs PW Lammers AR Cools 《Canadian Metallurgical Quarterly》1993,23(2):341-359
The pyrolytic behavior of inulin, a (2-->1)-linked fructofuranan, is described. Parallel investigations of the pyrolysis of glucose and of fructose were conducted to supplement the inulin results and to aid comparison with previous results from glucans. Effects of neutral and basic additives are emphasized. As with glucans, the addition of such additives (especially basic) increases the yields of the one-, two-, and three-carbon products (as well as of hexosaccharinolactones), while generally decreasing the yields of anhydro sugar and furan derivatives. The former products include glycolaldehyde, acetol, dihydroxy-acetone, acetic acid, formic acid, and lactic acid. Mechanistic speculations are made regarding the origins of these compounds, as well as of furan derivatives and saccharinic acid lactones. Parallels with alkaline degradation are considered. 相似文献