896 resultados para support vector
Resumo:
In this and a preceding paper, we provide an introduction to the Fujitsu VPP range of vector-parallel supercomputers and to some of the computational chemistry software available for the VPP. Here, we consider the implementation and performance of seven popular chemistry application packages. The codes discussed range from classical molecular dynamics to semiempirical and ab initio quantum chemistry. All have evolved from sequential codes, and have typically been parallelised using a replicated data approach. As such they are well suited to the large-memory/fast-processor architecture of the VPP. For one code, CASTEP, a distributed-memory data-driven parallelisation scheme is presented. (C) 2000 Published by Elsevier Science B.V. All rights reserved.
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Recent research has begun to provide support for the assumptions that memories are stored as a composite and are accessed in parallel (Tehan & Humphreys, 1998). New predictions derived from these assumptions and from the Chappell and Humphreys (1994) implementation of these assumptions were tested. In three experiments, subjects studied relatively short lists of words. Some of the Lists contained two similar targets (thief and theft) or two dissimilar targets (thief and steal) associated with the same cue (ROBBERY). AS predicted, target similarity affected performance in cued recall but not free association. Contrary to predictions, two spaced presentations of a target did not improve performance in free association. Two additional experiments confirmed and extended this finding. Several alternative explanations for the target similarity effect, which incorporate assumptions about separate representations and sequential search, are rejected. The importance of the finding that, in at least one implicit memory paradigm, repetition does not improve performance is also discussed.
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This study investigated a group support programme designed to improve self-awareness deficits and psychosocial functioning in a group of chronic patients (N = 21) with acquired brain injury (ABI). The participants were on average 8.6 years (range: 1-36 years) post-injury and were seen at the Brain Injury Association of Queensland, Australia. The assessment of participants involved two standardised measures of intellectual self-awareness with collateral reports from relatives. The present study introduced a new measure called the Self-Regulation Skills Interview (SRSI) which assessed higher levels of self awareness and self-regulation skills. Psychosocial functioning was assessed using a standardised self-report measure. At baseline the group had a relatively high level of intellectual self-awareness regarding their deficits, a low to moderate level of self-regulation skills, and significant psychosocial impairment. The participants were involved in a 16-week group programme which involved components of cognitive rehabilitation, cognitive-behavioural therapy, and social skills training. A post-intervention assessment indicated that participants had significantly improved levels of self-regulation skills and psychosocial functioning. A 6-month follow-up assessment indicated that overall, participants had maintained the gains made during the programme. The important role of self-regulation skills is emphasised as the principle factor contributing to the maintenance of the gains observed.
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This paper examines whether social support is a boundary-determining criterion in the job strain model of Karasek (1979). The particular focus is the extent to which different sources of social support, work overload and task control influence job satisfaction, depersonalization and supervisor assessments of work performance. Hypotheses are tested using prospective survey data from 80 clerical staff in a university setting. Results revealed 3-way interactions among levels of support (supervisor, co-worker, non-work), perceived task control and work overload on levels of work performance and employee adjustment (self-report). After controlling for levels of negative affect in all analyses, there was evidence that high levels of supervisor support mitigated against the negative effects of high strain jobs on levels of job satisfaction and reduced reported levels of depersonalization. Moreover, high levels of non-work support and co-worker support also mitigated against the negative effects of high strain jobs on levels of work performance. The results are discussed in terms of the importance of social support networks both at, and beyond, the work context.
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Dendritic cells (DCs) are the most potent professional antigen-presenting cells (APCs), which play a vital role in primary immune responses. Introducing genes into DCs will allow constitutive expression of the encoded proteins and thus prolong the presentation of the antigens derived therefrom. In addition, multiple and unidentified epitopes encoded by the entire tumor-associated antigen (TAA) gene may enhance T cell activation. This study demonstrated that an HIV-1-based lentiviral vector conferred efficient gene transfer to DCs. The transgene, murine tyrosinase-related protein 2 (mTRP-2), encodes a clinically relevant melanoma-associated antigen (MAA), which has been found to be a tumor rejection antigen for B16 melanoma. The transfer and proper processing of mTRP-2 in DCs, in terms of RNA transcription activity and protein expression, were verified by RT-PCR and specific antibody, respectively. Administration of mTRP-2 gene-modified DCs (DC-HR'CmT2) to C57BL/6 mice evoked strong protection against tumor challenge, for which the presence of CD4(+) and CD8(+) cells during both the priming and challenge phase was essential. In a therapy model, our results showed that four of seven mice with preestablished tumor remained tumor free for 80 days after therapeutic vaccination. Given the results shown in this study, mTRP-2 gene transfer to DCs provides a potential therapeutic strategy for the management of melanoma, especially in the early stage of the disease.
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Transfer of the herpes simplex virus type I thymidine kinase (HSV-TK) gene into tumor cells using virus-based vectors in conjunction with ganciclovir (GCV) exposure provides a potential gene therapy strategy for the treatment of cancer. Effective gene therapy,, depends on the efficient transfer and specific targeting of therapeutic genes and their protein products to target cells. The purpose of this study was to investigate the anti-tumor effect of Lentivirus-mediated and MUC1 antibody-targeted VP22-TK/GCV suicide gene therapy in animal models. Mouse models were generated with intraperitoneal injection of human epithelial ovarian cancer cells 3AO, which are MUC1-positive. HTV-1-based lentiviral vectors carrying VP22-TK or scFv-VP22-TK were prepared. The animals were injected intraperitoneally with lentivirus containing scFv-VP22-TK, VP22-TK followed by GCV treatment. Combined treatment of lentivirus-expressed scFv-VP22-TK or VP22-TK with GCV inhibited the proliferation and prolonged survival times compared with the control vector. The survival time of animals treated with scFv-VP22-TK/GCV was significantly longer than that of animals treated with VP22-TK/GCV (p = 0.006). Conclusion: Our results suggest that MUC1 antibody-targeted VP22-TK/GCV suicide gene therapy can efficiently inhibit ovarian tumor growth and increase survival in a nude mouse model of ovarian carcinoma. These data support the development of this method for human clinical trials.
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Phylogenetic hypotheses are presented for Pultenaea based on cpDNA (trnL-F and ndhF) and nrDNA ( ITS) sequence data. Pultenaea, as it is currently circumscribed, comprises six strongly supported lineages whose relationships with each other and 18 closely related genera are weak or conflicting among datasets. The lack of resolution among the six Pultenaea clades and their relatives appears to be the result of a rapid radiation, which is evident in molecular data from both the chloroplast and nuclear genomes. The molecular data provide no support for the monophyly of Pultenaea as it currently stands. Given these results, Pultenaea could split into many smaller genera. We prefer the taxonomically stable alternative of subsuming all 19 genera currently recognised in Pultenaea sensu lato (= the Mirbelia group) into an expanded concept of Pultenaea that would comprise similar to 470 species.
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Objective: to determine the relationship between age and in-hospital mortality of elderly patients, admitted to ICU, requiring and not requiring invasive ventilatory support. Design: prospective observational cohort study conducted over a period of 11 months. Setting: medical-surgical ICU at a Brazilian university hospital. Subjects: a total of 840 patients aged 55 years and older were admitted to ICU. Methods: in-hospital death rates for patients requiring and not requiring invasive ventilatory support were compared across three successive age intervals (55-64; 65-74 and 75 or more years), adjusting for severity of illness using the Acute Physiologic Score. Results: age was strongly correlated with mortality among the invasively ventilated subgroup of patients and the multivariate adjusted odds ratios increased progressively with every age increment (OR = 1.60, 95% CI = 1.01-2.54 for 65-74 years old and OR = 2.68, 95% CI = 1.58-4.56 for >= 75 years). For the patients not submitted to invasive ventilatory support, age was not independently associated with in-hospital mortality (OR = 2.28, 95% CI = 0.99-5.25 for 65-74 years old and OR = 1.95, 95% CI = 0.82-4.62 for >= 75 years old). Conclusions: the combination of age and invasive mechanical ventilation is strongly associated with in-hospital mortality. Age should not be considered as a factor related to in-hospital mortality of elderly patients not requiring invasive ventilatory support in ICU.
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Insulin-like growth factor I has similar mitogenic effects to insulin, a growth factor required by most cells in culture, and it can replace insulin in serum-free formulations for some cells. Chinese Hamster Ovary cells grow well in serum-free medium with insulin and transferrin as the only exogenous growth factors. An alternative approach to addition of exogenous growth factors to serum-free medium is transfection of host cells with growth factor-encoding genes, permitting autocrine growth. Taking this approach, we constructed an IGF-I heterologous gene driven by the cytomegalovirus promoter, introduced it into Chinese Hamster Ovary cells and examined the growth characteristics of Insulin-like growth factor I-expressing clonal cells in the absence of the exogenous factor. The transfected cells secreted up to 500 ng/10(6) cells/day of mature Insulin-like growth factor I into the conditioned medium and as a result they grew autonomously in serum-free medium containing transferrin as the only added growth factor. This growth-stimulating effect, observed under both small and large scale culture conditions, was maximal since no further improvement was observed in the presence of exogenous insulin.
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Background Metastatic renal cell carcinoma (mRCC) is one of the most treatment-resistant malignancies. Despite all new therapeutic advances, almost all patients develop resistance to treatment and cure is rarely seen. In the present study, we evaluated the antitumor effect of a bicistronic retrovirus vector encoding both endostatin (ES) and interleukin (IL)-2 using an orthotopic metastatic RCC mouse model. Methods Balb/C-bearing Renca cells were treated with NIH/3T3-LendIRES-IL-2-SN cells. In the survival studies, mice were monitored daily until they died. At the end of the in vivo experiment, serum levels of IL-2 and ES were measured, the lung was weighed, and the number of metastatic nodules, nodule area, tumor vessels and proliferation of tumor-infiltrating Renca cells were determined. Results Inoculation of NIH/3T3-LendIRES-IL-2-SN cells resulted in an increase in ES and IL-2 levels in the treated group (p < 0.05). There was a significant decrease in lung wet weight, lung nodule area and tumor vessels in the treated group compared to the control group (p < 0.001). The proliferation of Renca cells in the bicistronic-treated group was significantly reduced compared to the control group (p < 0.05). Kaplan-Meier survival curves showed that the probability of survival was significantly higher for mice submitted to bicistronic therapy (log-rank test, p = 0.0016). Bicistronic therapy caused an increase in the infiltration of CD4, CD4 interferon (IFN)gamma-producing, CD8, CD8 IFN gamma-producing and natural killer (CD49b) cells. Conclusions Retroviral bicistronic gene transfer led to the secretion of functional ES and IL-2 that was sufficiently active to: (i) inhibit tumor angiogenesis and tumor cell proliferation and (ii) increase the infiltration of immune cells (C) Copyright. 2011 John Wiley & Sons, Ltd.