Transforming remakes into demonstration models.
Explore the source record for details and available documents.
Acrylic Resins↗
SEARCH · Search PubMed
Results for “Transformer model”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[Migration of vulcanization accelerators (dithiocarbamic acid derivatives) and the products of their transformation from rubbers into model media and into milk].
Explore the source record for details and available documents.
Animals↗
Diminished nitric oxide production following administration of transforming growth factor-beta1 using a noninflammatory wound repair model.
The effects of transforming growth factor-beta1 (TGF-beta1) on systemic nitric oxide (NO) production and wound repair were evaluated using a noninflammatory mouse perforated mesentery connective tissue repair model. Urinary nitrates were monitored as a measure of NO production. TGF-beta1 [bovine serum albumin (BSA) carrier and TGF-beta1 BSA carrier free] were administered on days 0 and 1 and were evaluated in mice over a 10-day period. A significant decrease in the average postwounding urinary nitrate levels compared to prewounding levels was observed within the TGF-beta1 treatment group animals (P </= 0.001) with an insignificant change for the phosphate-buffered saline control animals (P </= 0.10). Additionally, TGF-beta1-treated animals showed significant connective tissue repair compared to controls without a concurrent increase in postwounding urinary nitrate levels, supporting the noninflammatory nature of the perforated mesentery model. Our findings suggest that an unforseen consequence of TGF-beta1 administration is diminished basal nitric oxide production. When using TGF-beta1 in a wound repair or other therapeutic model, the administration of an exogenous NO donor compound may be necessary in order to ensure homeostasis, thereby avoiding undesired physiological consequences due to diminished basal NO production.
Animals↗
Genetic parameters for stayability, stayability at calving, and stayability at weaning to specified ages for Hereford cows.
Genetic parameters for stayability to six ages (ST1, . . ., ST6), for five measures of stayability to calving (SC2, . . ., SC6), and for five measures of stayability to weaning (SW2, . . ., SW6), were estimated using records of 2,019 Hereford cows collected from 1964 to 1979 from a selection experiment with a control line and three lines selected for weaning weight, yearling weight, and an index of yearling weight and muscle score. The model included birth year of the cow as a fixed effect and the cow's sire as a random effect. Analyses were performed with 1) a generalized linear mixed model for binary data using a probit link with a penalized quasi-likelihood function, and 2) with a linear mixed model using REML. Genetic trends were estimated by regressing weighted means of estimated transmitting abilities (ETA) of sires by birth year of their daughters on birth year. Environmental trends were estimated by regressing solutions for year of birth on birth year. Estimates of heritability (SE) for ST were between 0.09 (0.08) and 0.30 (0.14) for threshold model and between 0.05 (0.04) and 0.19 (0.09) for linear model. Estimates of heritability from linear model analyses transformed to an underlying normal scale were between 0.09 and 0.35. Estimates of heritability (SE) for SC were between 0.29 (0.10) and 0.39 (0.11) and between 0.18 (0.09) and 0.25 (0.08) with threshold and linear models. Estimates of heritability transformed to an underlying normal scale were between 0.30 and 0.40. Estimates of heritability (SE) for SW were between 0.21 (0.14) and 0.47 (0.19) and between 0.12 (0.08) and 0.26 (0.12) with threshold and linear models, respectively. Estimates of heritability transformed to an underlying normal scale were between 0.21 and 0.50. Estimates of genetic and environmental trends for all lines were nearly zero for all traits. Correlations between ETA of sires for stayability to specific ages, for stayability to calving, and for stayability to weaning with threshold and linear models ranged from 0.09 to 0.82, from 0.68 to 0.90, and from 0.67 to 0.87, respectively. Selection for stayability would be possible in a breeding program and could be relatively effective as a result of the moderate estimates of heritability, which would allow selection of sires whose daughters are more likely to remain longer in the herd. Selection for weaning and yearling weights resulted in little correlated response for any of the measures of stayability.
Age Factors↗
Onset of direct 17-beta estradiol effects on proliferation and c-fos expression during oncogenesis of endometrial glandular epithelial cells.
In normal endometrial glandular epithelial cells (GEC), 17beta-estradiol (E2) enhances proliferation and c-fos expression only in the presence of growth factors. On the contrary, growth factors are not required for the E2 effects in cancerous cells. Thus, a repression of E2 action could exist in normal cells and be turned off in cancerous cells, allowing a direct estrogen-dependent proliferation. To verify this hypothesis, we established immortalized and transformed cell models, then investigated alterations of E2 effects during oncogenesis. SV40 large T-antigen was used to generate immortalized GEC model (IGEC). After observation of telomerase reactivation, IGEC model was transfected by activated c-Ha-ras to obtain transformed cell lines (TGEC1 and TGEC2). The phenotypic, morphological, and genetic characteristics of these models were determined before studying the E2 effects. In IGEC, the E2 action on proliferation and c-fos expression required the presence of growth factors, as observed in GECs. In TGECs, this action arose in the absence of growth factors. After IGEC transformation, the activation of ras pathway would substitute the priming events required for the release of repression in GEC and IGEC and thus permit direct E2 effects. Our cell models are particularly suitable to investigate alterations of gene regulation by E2 during oncogenesis.
Animals↗
System modeling and optimization of Fourier holographic memory.
A new fast-Fourier-transform-based model of a page-oriented holographic data-storage system is presented. The model accounts for essential system and storage material features (e.g. diffraction, noises, and saturation) and provides reliable results in the form of output images, histograms, or bit-error rates. The model is built on a modular basis and provides the possibility of working with different system versions, key components, and storage materials. Applications of the method are presented through examples of optimization of the data density, reference beam size at Gaussian beam illumination, and calculation of the storage medium's positioning tolerances in accordance with the results of test measurements.
Journal Article↗
Working smart: turning everyday commitments into scholarly outcomes.
BACKGROUND: This article offers a model for transforming routine professional responsibilities into scholarly products. METHOD: Using Boyer's model of scholarship as a guide, the authors were able to transform a professional commitment into the scholarship of teaching and learning, practice and engagement, and discovery. RESULTS: The authors were able to conduct a research study, educate graduate students, and provide important data about nursing to a statewide project. CONCLUSION: Working smart requires transforming existing commitments and resources into opportunities for creating scholarly products that are shared with the broader nursing community.
Connecticut↗
Inhibition of tubular morphogenesis in human microvascular endothelial cells by co-culture with chondrocytes and involvement of transforming growth factor beta: a model for avascularity in human cartilage.
Tube formation in collagen gel was induced in human omental microvascular endothelial (HOME) cells in the presence of epidermal growth factor (EGF) or transforming growth factor-alpha (TGF-alpha). TGF-alpha enhanced the expression of the tissue type plasminogen activator (t-PA) gene, whereas TGF-beta increased the expression of the PA inhibitor-1 (PAI-1) gene and inhibited that of the t-PA gene. TGF-beta inhibited the tube formation of HOME cells in type I collagen gel that was enhanced in response to TGF-alpha. We have recently established an angiogenesis model in vitro in which vascular endothelial cells on type I collagen gel in an inner chamber are co-cultured with other types of cells in an outer chamber. Here we examined whether the EGF/TGF-alpha-induced tube formation in HOME cells was modulated by human chondrocytes co-culture in the outer chamber. TGF-alpha-dependent tube formation of HOME cells was inhibited when human chondrocytes were co-cultured in the outer chamber. This chondrocyte-induced inhibition of tube formation was partly abrogated by co-administration of anti-TGF-beta antibody. These findings suggest that TGF-beta is partly involved in the human chondrocyte-dependent inhibition of tube formation by human microvascular endothelial cells. This is the first model system demonstrating that avascularity of human chondrocytes is partly due to TGF-beta family produced from them.
Cartilage↗
Recognizing people seen in events via dynamic "mug shots".
This study examined effects of an event and dynamic mug shots on facial recognition. Witnesses saw either a film of a liquor store holdup staged by six perpetrators, slides of the same targets, or freeze-framed views from the filmed event. Slides of different facial views of targets among 12 foils, or dynamic 180 degrees mug shots of the same men, or multiple static views were administered 24 hr later in yes-no recognition tests. Recognition (d') was poorer for the same men seen in the event than in slides, but better for dynamic than for static mug shots. Nondynamic event characteristics were responsible for poor recognition of people seen in events, whereas dynamic aspects of facial transformations, not multiple views, seemed responsible for the superiority of dynamic mug shots. The implications of these results for issues of ecological validity of traditional face recognition methodology and for static feature models vs. dynamic transformation models of face recognition are discussed.
Adult↗
A standardized boundary element method volume conductor model.
OBJECTIVES: We used a 3-compartment boundary element method (BEM) model from an averaged magnetic resonance image (MRI) data set (Montreal Neurological Institute) in order to provide simple access to realistically shaped volume conductor models for source reconstruction, as compared to individually derived models. The electrode positions were transformed into the model's coordinate system, and the best fit dipole results were transformed back to the original coordinate system. The localization accuracy of the new approach was tested in a comparison with simulated data and with individual BEM models of epileptic spike data from several patients. METHODS: The standard BEM model consisted of a total of 4770 nodes, which describe the smoothed cortical envelope, the outside of the skull, and the outside of the skin. The electrode positions were transformed to the model coordinate system by using 3-5 fiducials (nasion, left and right preauricular points, vertex, and inion). The transformation consisted of an averaged scaling factor and a rigid transformation (translation and rotation). The potential values at the transformed electrode positions were calculated by linear interpolation from the stored transfer matrix of the outer BEM compartment triangle net. After source reconstruction the best fit dipole results were transformed back into the original coordinate system by applying the inverse of the first transformation matrix. RESULTS: Test-dipoles at random locations and with random orientations inside of a highly refined reference BEM model were used to simulate noise-free data. Source reconstruction results using a spherical and the standardized BEM volume conductor model were compared to the known dipole positions. Spherical head models resulted in mislocation errors at the base of the brain. The standardized BEM model was applied to averaged and unaveraged epileptic spike data from 7 patients. Source reconstruction results were compared to those achieved by 3 spherical shell models and individual BEM models derived from the individual MRI data sets. Similar errors to that evident with simulations were noted with spherical head models. Standardized and individualized BEM models were comparable. CONCLUSIONS: This new approach to head modeling performed significantly better than a simple spherical shell approximation, especially in basal brain areas, including the temporal lobe. By using a standardized head for the BEM setup, it offered an easier and faster access to realistically shaped volume conductor models as compared to deriving specific models from individual 3-dimensional MRI data.
Brain↗
Effects of MAP kinase inhibitors on epidermal growth factor-induced neoplastic transformation of human keratinocytes.
We previously reported data regarding the mechanism of neoplastic transformation in JB6 Cl41 mouse skin epidermal cells. However, experimental in vitro models for studying neoplastic transformation of human cells could provide further insight into the mechanisms of human cancer development. In this study, we have established a neoplastic transformation model with HaCaT cells, a human keratinocyte cell line, and showed the usefulness of this cell line for studying the mechanisms of neoplastic transformation. Epidermal growth factor (EGF) treatment induced a dose-dependent anchorage-independent cell transformation in HaCaT cells. Furthermore, PD98059, a mitogen-activated protein (MAP) kinase/ERK kinase (MEK) inhibitor, or SP600125, c-Jun N-terminal kinase (JNK) inhibitor, decreased cell growth, EGF-induced DNA synthesis and transformation. Unlike observations in the JB6 mouse epidermal cell model, SB203580, a stress-activated protein kinase-2/p38 alpha and beta (p38) inhibitor, increased EGF-induced transformation in HaCaT cells. These results suggest that extracellular-signal regulated kinase (ERK), JNK, or p38 are implicated in EGF-induced neoplastic transformation of human cells.
Cell Line↗
Taking the eagle's view: using Watson's conceptual model to investigate the extraordinary and transformative experiences of nurse healers.
Watson's conceptual model of a caring-healing transpersonal understanding of nursing was used to underpin a hermeneutic phenomenological study of the extraordinary and transformational experiences of nurse healers. The 5 essential themes uncovered from the analysis of interviews with 11 nurse healers--Belonging & Connecting, Opening to Spirit, Summoning, Wounding & Healing Journey, and Living as a Healer--are set out, along with the overarching theme "Walking Two Worlds." Foundational understandings of Watson's model as they relate to the findings, and theoretical aspects, are discussed, and potential contributions of this study to the ongoing evolution of Watson's conceptual model are articulated.
Empathy↗
The transformation rate of moles (melanocytic nevi) into cutaneous melanoma: a population-based estimate.
BACKGROUND: Moles, or melanocytic nevi, are both markers of an increased risk of cutaneous melanoma and direct precursor lesions. Recent strategies to reduce the burden of advanced disease have focused on early detection and ongoing surveillance of moles for malignant degeneration. Inherent in this approach is the notion that moles exhibit a certain risk of transformation into melanoma; however, this risk is unknown. OBJECTIVE: To estimate the risk of moles transforming into cutaneous melanoma. DESIGN: We first constructed a model of transformation based on the assumption that the minimal number of moles turning into cutaneous melanoma per year is roughly equivalent to the number of melanomas diagnosed each year with associated nevic components. The annual risk was then calculated as the number of mole-associated melanomas diagnosed in 1 year (stratified by 10-year age groups) divided by the number of moles in a the same 10-year age group. We also estimated the cumulative risk during the lifetime of an individual mole by using a modification of the standard life table method. RESULTS: The annual transformation rate of any single mole into melanoma ranges from 0.0005% or less (ie, </=1 in 200,000) for both men and women younger than 40 years to 0.003% (about 1 in 33,000) for men older than 60 years. The rate is similar between men and women younger than 40 years but becomes substantially higher for men older than 40 years. For a 20-year-old individual, the lifetime risk of any selected mole transforming into melanoma by age 80 years is approximately 0.03% (1 in 3,164) for men and 0.009% (1 in 10,800) for women. CONCLUSIONS: The risk of any particular mole becoming melanoma is low, especially in younger individuals. However, since moles can disappear, ones that persist into old age have an increased risk of malignant degeneration. For young people with innumerable moles and no other associated risk factors, systematic excision of benign-appearing lesions would be of limited benefit.
Adult↗
The Thom Award address. Industrial mycology and the new genetics.
The genetic investigation of fungi has been extended substantially by DNA-mediated transformation, providing a supplement to more conventional genetic approaches based upon sexual and parasexual processes. Initial transformation studies with the yeast Saccharomyces cerevisiae provided the model for transformation systems in other fungi with regard to methodology, vector construction and selection strategies. There are, however, certain differences between S. cerevisiae and filamentous fungi with regard to type of genomic insertion and the availability of shuttle vectors. Single-site linked insertions are common in yeast due to the high level of homology required for recombination between vectored and genomic sequences, whereas mycelial fungi often show a high frequency of heterologous and unlinked insertions, often in the form of random and multiple-site integrations. While extrachromosomally-maintained or replicative vectors are readily available for use with yeasts, such vectors have been difficult to construct for use with filamentous fungi. The development of vectors for replicative transformation with these fungi awaits further study. It is proposed that replicative vectors may be inherently less efficient for use with mycelial fungi relative to yeasts, since the mycelium, as an extended and semicontinuous network of cells, may delimit an adequate diffusion of the vector carrying the selectable gene, thus leading to a high frequency of abortive or unstable transformants.
Fungi↗
Enumeration of the simian virus 40 early region elements necessary for human cell transformation.
While it is clear that cancer arises from the accumulation of genetic mutations that endow the malignant cell with the properties of uncontrolled growth and proliferation, the precise combinations of mutations that program human tumor cell growth remain unknown. The study of the transforming proteins derived from DNA tumor viruses in experimental models of transformation has provided fundamental insights into the process of cell transformation. We recently reported that coexpression of the simian virus 40 (SV40) early region (ER), the gene encoding the telomerase catalytic subunit (hTERT), and an oncogenic allele of the H-ras gene in normal human fibroblast, kidney epithelial, and mammary epithelial cells converted these cells to a tumorigenic state. Here we show that the SV40 ER contributes to tumorigenic transformation in the presence of hTERT and oncogenic H-ras by perturbing three intracellular pathways through the actions of the SV40 large T antigen (LT) and the SV40 small t antigen (ST). LT simultaneously disables the retinoblastoma (pRB) and p53 tumor suppressor pathways; however, complete transformation of human cells requires the additional perturbation of protein phosphatase 2A by ST. Expression of ST in this setting stimulates cell proliferation, permits anchorage-independent growth, and confers increased resistance to nutrient deprivation. Taken together, these observations define the elements of the SV40 ER required for the transformation of human cells and begin to delineate a set of intracellular pathways whose disruption, in aggregate, appears to be necessary to generate tumorigenic human cells.
Antigens, Viral, Tumor↗
Methods and approaches to determine "optimal" quality for clinical chemical data.
Although clinical reasoning and decision-making may be very complex, there are methods to perform both piecemeal and more complete optimizations with regard to the use of clinical chemical data and for assessing quality specification. Some methods and approaches are described and illustrated with examples: (i) rules for propagation of errors in simple algebraic/statistical transformations; (ii) systems and sensitivity analysis using biochemical/pathophysiological simulation models; (iii) systems and sensitivity analysis of simulated clinical classification and decision processes. It is concluded that the possible gain of useful information by improving analytical and pre-analytical quality should be related to the often more important aspects of test selection test and test combination, period and frequency of observation, and the use of correct conceptual models for transformation of data.
Chemistry Techniques, Analytical↗
Induction of thioguanine-resistant mutations in human uroepithelial cells by 4-aminobiphenyl and its N-hydroxy derivatives.
The mutagenic potentials of the human bladder carcinogen 4-amino-biphenyl (ABP) and three of its proximate carcinogenic metabolites, N-hydroxy-4-aminobiphenyl (N-OH-ABP), N-hydroxy-4-acetylaminobiphenyl (N-OH-AABP) and N-acetoxy-4-acetylaminobiphenyl (N-OAc-AABP) were tested on a prime human target cell type for carcinogenesis, human uroepithelial cells (HUC). SV-HUC (PC), a near diploid, clonally derived, nontumorigenic SV40-immortalized human uroepithelial cell line that is transformable to tumorigenicity after exposure to ABP and its metabolites, was used for quantitative mutation assays. The end point used was the induction of mutations in the hypoxanthine-guanine phosphoribosyltransferase (HGPRT) locus, selected using 6-thioguanine resistance (TGr). A single, 24-h exposure of SV-HUC to ABP, N-OH-ABP, N-OH-AABP, or N-OAc-AABP caused a statistically significant, dose-dependent increase in mutation frequency resulting in a 2-30-fold increase in the number of TGr mutants in carcinogen-exposed groups compared to untreated controls. These chemicals were similarly mutagenic towards MC-T11, an SV-HUC-derived low grade tumor cell line that was also shown to be responsive to transformation (in a separate study) by ABP, N-OH-ABP, or N-OH-AABP as judged by the generation of higher grade tumors. In contrast, the mutagenic potencies of ABP and N-OH-ABP were lower when tested on a subclone of SV-HUC (BC) that is refractory to transformation by these chemicals. Thus, these data support a model of transformation in which ABP as well as its metabolites contribute to tumorigenic transformation and neoplastic progression of HUC by inducing mutations in susceptible target cell genes.
Aminobiphenyl Compounds↗
[Genetically transformed plant roots as a model for studying specific metabolism and symbiotic contacts of the root system].
Genetic transformation of plants mediated by Ri plasmid of Agrobacterium rhizogenes occupies a special place in plant cell engineering, since this technique based on a natural phenomenon allows cultivation of separately growing roots on hormone-free media. Application of wild-type unmodified agrobacterial strains allows us to obtain root cultures capable of long-term growth in vitro due to an increased sensitivity of the cells to auxins while other biochemical properties remain unaltered. A collection of pRi T-DNA transformed roots of certain dicotyledons was constructed; some strains of it are used to study synthesis of secondary metabolites in root cells. The in vitro cultivated roots could synthesize root-specific metabolites, which allows their large-scale application for biotechnological production of ecologically pure crude drugs. Cocultivation of pRi T-DNA transformed roots with arbuscular mycorrhizal fungi makes possible vital study of all stages of obligate symbiont development and interaction with plant roots. Mixed axenic culture of AM fungi and pRi T-DNA transformed plants can be used to construct a collection of the most valuable endomycorrhizal fungal species and to produce considerable quantities of homogeneous fungal inoculums.
Coculture Techniques↗