University of Westminster

About: University of Westminster is a education organization based out in London, United Kingdom. It is known for research contribution in the topics: Population & Context (language use). The organization has 2944 authors who have published 8426 publications receiving 200236 citations. The organization is also known as: Westminster University & Royal Polytechnic Institution.

Nonequivalence of on-line and paper-and-pencil psychological tests: The case of the prospective memory questionnaire

Abstract: There is growing evidence that Internet-mediated psychological tests can have satisfactory psychometric properties and can measure the same constructs as traditional versions. However, equivalence cannot be taken for granted. The prospective memory questionnaire (PMQ; Hannon, Adams, Harrington, Fries-Dias, & Gibson, 1995) was used in an on-line study exploring links between drug use and memory (Rodgers et al., 2003). The PMQ has four factor-analytically derived subscales. In a large (N = 763) sample tested via the Internet, only two factors could be recovered; the other two subscales were essentially meaningless. This demonstration of nonequivalence underlines the importance of on-line test validation. Without examination of its psychometric properties, one cannot be sure that a test administered via the Internet actually measures the intended construct.

Didox (a novel ribonucleotide reductase inhibitor) overcomes Bcl-2 mediated radiation resistance in prostate cancer cell line PC-3.

Abstract: In this study, we investigated the influence of Bcl-2 overexpression on the radiosensitizing potential of Didox (DX; 3,4-Dihydroxybenzohydroxamic acid), a novel ribonucleotide reductase inhibitor, in p53-null prostate cancer cell line PC-3. The PC-3 cells were transfected with vector alone or ectopically overexpressed with CMV-Bcl-2 construct. The effect of radiation (IR) or DX alone and in combination (pre and post IR exposure of DX) on cell survival was determined by colony-forming assay. The impact of these two treatments on the cell cycle was determined by flow cytometry. To further understand the molecular mechanism of DX-mediated radiosensitization, induction of pro-survival and pro-apoptotic factors were determined by Western blot and gel-shift assays respectively. When compared to PC-3/Bcl-2 cells (SF(2)=0.84; D(0)=437cGy), the PC-3/vector cells (SF(2)=0.4; D(0)=235cGy) were significantly sensitive to ionizing radiation (p<0.001). Exposure of DX at 5 microM concentration prior or post to radiation in both PC-3/vector and PC-3/Bcl-2 transfectants caused an increase in radiation enhancement ratios. A significant reduction in G(2)M phase was observed in cells exposed to DX post IR when compared to cells exposed to IR alone. Exposure to DX after radiation in PC-3/vector significantly abrogated radiation-induced Bcl-2 upregulation, with a concomitant induction of bax protein. In PC-3/Bcl-2 transfectants, DX exposure after IR caused an induction of bax protein. Gel shift assays indicated that in PC-3/vector cells when exposed to IR caused an induction of NFkappa-B activity however, DX down regulated the NFkappa-B activity. Radiation-induced NFkappa-B activity was abrogated in pre and post DX exposure in combination with IR. These findings indicate that DX mediates a potent radiosensitizing effect in p53 null prostate cancer cells by overcoming radiation induced NFkappa-B activity and Bcl-2 expression.

Stressful life events are associated with low secretion rates of immunoglobulin A in saliva in the middle aged and elderly.

Abstract: Whether chronic stress experience is related to downregulation of secretory immunoglobulin A (S-IgA) was tested in two substantial cohorts, one middle aged (N = 640) and another elderly (N = 582), comprising similar numbers of men (N = 556) and women (N = 666) and manual (N = 606) and non-manual (N = 602) workers. Participants indicated from a list of major stressful life events, up to six, they had experienced in the past 2 years. They also rated how disruptive and stressful the events were, at the time and now, as well as their perceived seriousness; the products of these impact values and event frequency were adopted as measures of stress load. From unstimulated 2-min saliva samples, saliva volume and S-IgA concentration were measured, and S-IgA secretion rate determined as their product. There was a negative association between the stress load measures and the S-IgA secretion rate, still evident following adjustment for such variables as smoking and saliva volume. The associations also withstood adjustment for sex, cohort, and household occupational status. Although these associations are small in terms of the amount of variance explained, they nonetheless suggest that chronic stress experience either decreases IgA production by the local plasma cells or reduces the efficiency with which S-IgA is transported from the glandular interstitium into saliva. Given the importance of S-IgA in immune defence at mucosal surfaces and the frequency with which infections are initiated at these surfaces, S-IgA downregulation could be a means by which chronic stress increases susceptibility to upper respiratory tract infection.

Cross-modality priming in stem completion reflects conscious memory, but not voluntary memory.

Abstract: A comparison of incidental and intentional stem-completion tests confirmed that cross-modality priming occurs when performance conforms completely to the retrieval intentionality criterion, indi­ cating involuntary-not voluntary-retrieval in the incidental test. However, an on-line measure of awareness in the incidental test, and a process-dissociation analysis of the intentional test, indicated only within-modality, but not cross-modality, transfer of involuntary retrieval that is unaccompanied by memorial awareness, These results imply that conscious memory should not be equated with vol­ untary retrieval, and unconscious memory should not be equated with involuntary retrieval, because involuntary retrieval can be accompanied by memorial awareness, Incidental perceptual tests of memory typically re­ quire participants to complete or identify an incomplete or degraded external stimulus (e.g., a word stem or a briefly flashed word). Prior study of the intact version of a test item facilitates or "primes" current performance. This priming is characterized as perceptual because it often varies with the degree ofperceptual match between study and test items: In a visual test, for example, priming de­ creases markedly when study is auditory compared to when it is visual (for reviews, see Richardson-Klavehn & Bjork, 1988; Roediger & McDermott, 1993). Such find­ ings, among others, have led to the hypothesis that prim­ ing depends on modality-specific perceptualrepresenta­