125 resultados para estrogen E2


Relevância:

10.00% 10.00%

Publicador:

Resumo:

We report calculations of energy levels, radiative rates, oscillator strengths and line strengths for transitions among the lowest 345 levels of Ti X. These include 146 levels of the n 3 configurations and 86 of 3s 24ℓ, 3s25ℓ and 3s3p4ℓ, plus some of the 3s26ℓ, 3p24ℓ and 3s3p5ℓ levels. The general-purpose relativistic atomic structure package and flexible atomic code are adopted for the calculations. Radiative rates, oscillator strengths and line strengths are provided for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2) and magnetic quadrupole (M2) transitions among the 345 levels, although calculations have been performed for a much larger number of levels. Comparisons are made with existing results and the accuracy of the data is assessed. Additionally, lifetimes for all 345 levels are listed. Extensive comparisons of lifetimes are made for the lowest 40 levels, for which discrepancies with recent theoretical work are up to 30%. Discrepancies in lifetimes are even larger, up to a factor of four, for higher excited levels. Furthermore, the effect of large configuration interaction (CI) is found to be insignificant for both the energies and lifetimes for the lowest 40 levels of Ti X which belong to the 3s23p, 3s3p2, 3s23d, 3p3 and 3s3p3d configurations. However, the contribution of CI is more appreciable for the energy levels and radiative rates among higher excited levels. Our listed energy levels are estimated to be accurate to better than 1% (within 0.1 Ryd), whereas results for other parameters are probably accurate to better than 20%. © 2013 The Royal Swedish Academy of Sciences.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We report calculations of energy levels, radiative rates and electron impact excitation cross sections and rates for transitions in He-like Fe XXV, Co XXVI, Ni XXVII, Cu XXVIII and Zn XXIX. The grasp (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates. For determining the collision strengths and subsequently the excitation rates, the Dirac atomic R-matrix code (darc) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 49 levels of each ion. Additionally, theoretical lifetimes are listed for all 49 levels of the above five ions. Collision strengths are averaged over a Maxwellian velocity distribution and the effective collision strengths obtained listed over a wide temperature range up to 10 7.7 K. Comparisons are made with similar data obtained using the flexible atomic code (fac) to highlight the importance of resonances, included in calculations with darc, in the determination of effective collision strengths. Discrepancies between the collision strengths from darc and fac, for some transitions, are also discussed. Finally, discrepancies between the present results of effective collision strengths with the darc code and earlier semi-relativistic R-matrix data are noted over a wide range of electron temperatures for many transitions in all ions. 

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We report calculations of energy levels, radiative rates and electron impact excitation cross sections and rates for transitions in He-like Ga XXX, Ge XXXI, As XXXII, Se XXXIII and Br XXXIV. The grasp (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates. For determining the collision strengths, and subsequently the excitation rates, the Dirac atomic R-matrix code (darc) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 49 levels of each ion. Additionally, theoretical lifetimes are provided for all 49 levels of the above five ions. Collision strengths are averaged over a Maxwellian velocity distribution and the effective collision strengths obtained listed over a wide temperature range up to 108 K. Comparisons are made with similar data obtained using the flexible atomic code (fac) to highlight the importance of resonances, included in calculations with darc, in the determination of effective collision strengths. Discrepancies between the collision strengths from darc and fac, particularly for some forbidden transitions, are also discussed. Finally, discrepancies between the present results for effective collision strengths with the darc code and earlier semi-relativistic R-matrix data are noted over a wide range of electron temperatures for many transitions in all ions. © 2013 The Royal Swedish Academy of Sciences.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We report calculations of energy levels, radiative rates, and electron impact excitation rates for transitions in Li-like ions with 21≤Z≤28. The General-Purpose Relativistic Atomic Structure Package is adopted for calculating energy levels and radiative rates, while for determining the collision strengths and subsequently the excitation rates, the Dirac Atomic R-matrix Code is used. Oscillator strengths, radiative rates, and line strengths are listed for all E1, E2, M1, and M2 transitions among the lowest 24 levels of the Li-like ions considered. Collision strengths have been averaged over a Maxwellian velocity distribution, and the effective collision strengths obtained are given over a wide temperature range up to 107.8 K. Additionally, lifetimes are listed for all calculated levels of these ions. Finally, extensive comparisons are made with results available in the literature, as well as with our analogous calculations for all parameters with the Flexible Atomic Code, in order to assess the accuracy of the results.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We report calculations of energy levels, radiative rates and electron impact excitation cross sections and rates for transitions in Be-like Ti XIX. The general-purpose relativistic atomic structure package is adopted for calculating energy levels and radiative rates. For determining the collision strengths and subsequently the excitation rates, the Dirac atomic R-matrix code (darc) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 98 levels of the n≤ 4 configurations. Additionally, theoretical lifetimes are listed for all 98 levels. Collision strengths are averaged over a Maxwellian velocity distribution and the effective collision strengths obtained listed over a wide temperature range up to 10 7.7K. Comparisons are made with similar data obtained from the flexible atomic code (fac) to highlight the importance of resonances, included in calculations with darc, in the determination of effective collision strengths. Discrepancies between the collision strengths from darc and fac, particularly for forbidden transitions, are also discussed. 

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We report calculations of energy levels, radiative rates and electron impact excitation cross sections and rates for transitions in He-like Kr XXXV. The grasp (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates. For determining the collision strengths and subsequently the excitation rates, the Dirac Atomic R-matrix Code (darc) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 49 levels. Additionally, theoretical lifetimes are listed for all 49 levels. Collision strengths are averaged over a Maxwellian velocity distribution and the effective collision strengths obtained listed over a wide temperature range up to 10 8.1K. Comparisons are made with similar data obtained with the Flexible Atomic Code (fac) to assess the accuracy of the results and to highlight the importance of resonances, included in calculations with darc, in the determination of effective collision strengths. Differences between the collision strengths from darc and fac, particularly for forbidden transitions, are also discussed. Finally, discrepancies between the present results of effective collision strengths from the darc code and earlier semi-relativistic R-matrix data are noted over a wide range of electron temperatures for many transitions of KrXXXV. 

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We report calculations of energy levels, radiative rates and electron impact excitation cross sections and rates for transitions in He-like Ti XXI, V XXII, Cr XXIII and Mn XXIV. grasp (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates. For determining the collision strengths and subsequently the excitation rates, the Dirac atomic R-matrix code (darc) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 49 levels of each ion. Additionally, theoretical lifetimes are listed for all the 49 levels of the above four ions. Collision strengths are averaged over a Maxwellian velocity distribution and the effective collision strengths obtained listed over a wide temperature range up to 10 7.5K. Comparisons are made with similar data obtained using the flexible atomic code (fac) to highlight the importance of resonances, included in calculations with darc, in the determination of effective collision strengths. Discrepancies between the collision strengths from darc and fac, in particular for forbidden transitions, are also discussed. Finally, discrepancies between the present results for effective collision strengths with the darc code and earlier semi-relativistic R-matrix data are noted over a wide range of electron temperatures for many transitions in all ions. 

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We report calculations of energy levels, radiative rates, and electron impact excitation rates for transitions in Li-like ions with 12≤Z≤20. The grasp (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates, while for determining the collision strengths and subsequently the excitation rates, the Dirac atomic R-matrix code is used. Oscillator strengths, radiative rates, and line strengths are reported for all E1, E2, M1, and M2 transitions among the lowest 24 levels of the Li-like ions considered. Collision strengths have been averaged over a Maxwellian velocity distribution, and the effective collision strengths obtained are reported over a wide temperature range up to 107.4 K. Additionally, lifetimes are also listed for all calculated levels of the ions. Finally, extensive comparisons are made with results available in the literature, as well as with our parallel calculations for all parameters with the Flexible Atomic Code, in order to assess the accuracy of the reported results. 

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We report energy levels, radiative rates (A-values) and lifetimes for the astrophysically important Be-like ion C III. For the calculations, 166 levels belonging to the n ≤ 5 configurations are considered and the GRASP (General-purpose Relativistic Atomic Structure Package) is adopted. Einstein A-coefficients are provided for all E1, E2, M1 and M2 transitions, while lifetimes are compared with available measurements as well as theoretical results, and no large discrepancies noted. Our energy levels are assessed to be accurate to better than 1 per cent for a majority of levels, and A-values to better than 20 per cent for most transitions. Collision strengths are also calculated, for which the Dirac Atomic R-matrix Code (DARC) is used. A wide energy range, up to 21 Ryd, is considered and resonances resolved in a fine energy mesh in the thresholds region. The collision strengths are subsequently averaged over a Maxwellian velocity distribution to determine effective collision strengths up to a temperature of 8.0 ×10[5]K, sufficient for most astrophysical applications. Our data are compared with the recent R-matrix calculations of Fernández-Menchero et al., and significant differences (up to over an order of magnitude) are noted for several transitions over the complete temperature range of the results.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Energies and lifetimes are reported for the lowest 136 levels of Fe XIV, belonging to the (1s(2)2s(2)2p(6)) 3s(2)3p, 3s(3)p(2), 3s(2)3d, 3p(3), 3s(3)p(3)d, 3p(2)3d, 3s(3)d(2), 3p(3)d(2) and 3s(2)4l configurations. Additionally, radiative rates, oscillator strengths and line strengths are calculated for all electric dipole (E1), magnetic dipole (M1), electric quadrupole (E2) and magnetic quadrupole (M2) transitions. Theoretical lifetimes determined from these radiative rates for most levels show satisfactory agreement with earlier calculations, a swell as with measurements. Electron impact excitation collision strengths are also calculated with the Dirac atomic R-matrix code (DARC) over a wide energy range up to 260 Ryd. Furthermore, resonances have been resolved in a fine energy mesh to determine effective collision strengths, obtained after integrating the collision strengths over a Maxwellian distribution of electron velocities. Results are listed for all 9180 transitions among the 136 levels over a wide range of electron temperatures, up to 10(7.1) K. Comparisons are made with available results in the literature, and the accuracy of the present data is assessed.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

OBJECTIVE: Ovarian cancer is the most lethal gynecological malignancy that affects women. Recent data suggests that the disease may originate in the fallopian fimbriae; however, the anatomical origin of ovarian carcinogenesis remains unclear. This is largely driven by our lack of knowledge regarding the structure and function of normal fimbriae and the relative paucity of models that accurately recapitulate the in vivo fallopian tube. Therefore, a human three-dimensional (3D) culture system was developed to examine the role of the fallopian fimbriae in serous tumorigenesis.

METHODS: Alginate matrix was utilized to support human fallopian fimbriae ex vivo. Fimbriae were cultured with factors hypothesized to contribute to carcinogenesis, namely; H2O2 (1mM) a mimetic of oxidative stress, insulin (5μg/ml) to stimulate glycolysis, and estradiol (E2, 10nM) which peaks before ovulation. Cultures were evaluated for changes in proliferation and p53 expression, criteria utilized to identify potential precursor lesions. Further, secretory factors were assessed after treatment with E2 to identify if steroid signaling induces a pro-tumorigenic microenvironment.

RESULTS: 3D fimbriae cultures maintained normal tissue architecture up to 7days, retaining both epithelial subtypes. Treatment of cultures with H2O2 or insulin significantly induced proliferation. However, p53 stabilization was unaffected by any particular treatment, although it was induced by ex vivo culturing. Moreover, E2-alone treatment significantly induced its canonical target PR and expression of IL8, a factor linked to poor outcome.

CONCLUSIONS: 3D alginate cultures of human fallopian fimbriae provide an important microphysiological model, which can be further utilized to investigate serous tumorigenesis originating from the fallopian tube.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

OBJECTIVE: Progesterone (P4) plays a central role in women's health. Synthetic progestins are used clinically in hormone replacement therapy (HRT), oral contraceptives, and for the treatment of endometriosis and infertility. Unfortunately, synthetic progestins are associated with side effects, including cardiovascular disease and breast cancer. Botanical dietary supplements are widely consumed for the alleviation of a variety of gynecological issues, but very few studies have characterized natural compounds in terms of their ability to bind to and activate progesterone receptors (PR). Kaempferol is a flavonoid that functions as a non-steroidal selective progesterone receptor modulator (SPRM) in vitro. This study investigated the molecular and physiological effects of kaempferol in the ovariectomized rat uteri.

METHODS: Since genistein is a phytoestrogen that was previously demonstrated to increase uterine weight and proliferation, the ability of kaempferol to block genistein action in the uterus was investigated. Analyses of proliferation, steroid receptor expression, and induction of well-established PR-regulated targets Areg and Hand2 were completed using histological analysis and qPCR gene induction experiments. In addition, kaempferol in silico binding analysis was completed for PR. The activation of estrogen and androgen receptor signalling was determined in vitro.

RESULTS: Molecular docking analysis confirmed that kaempferol adopts poses that are consistent with occupying the ligand-binding pocket of PRA. Kaempferol induced expression of PR regulated transcriptional targets in the ovariectomized rat uteri, including Hand2 and Areg. Consistent with progesterone-l ke activity, kaempferol attenuated genistein-induced uterine luminal epithelial proliferation without increasing uterine weight. Kaempferol signalled without down regulating PR expression in vitro and in vivo and without activating estrogen and androgen receptors.

CONCLUSION: Taken together, these data suggest that kaempferol is a unique natural PR modulator that activates PR signaling in vitro and in vivo without triggering PR degradation.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Müllerian inhibiting substance (MIS), a member of the transforming growth factor-beta superfamily, induces regression of the Müllerian duct in male embryos. In this report, we demonstrate MIS type II receptor expression in normal breast tissue and in human breast cancer cell lines, breast fibroadenoma, and ductal adenocarcinomas. MIS inhibited the growth of both estrogen receptor (ER)-positive T47D and ER-negative MDA-MB-231 breast cancer cell lines, suggesting a broader range of target tissues for MIS action. Inhibition of growth was manifested by an increase in the fraction of cells in the G(1) phase of the cell cycle and induction of apoptosis. Treatment of breast cancer cells with MIS activated the NFkappaB pathway and selectively up-regulated the immediate early gene IEX-1S, which, when overexpressed, inhibited breast cancer cell growth. Dominant negative IkappaBalpha expression ablated both MIS-mediated induction of IEX-1S and inhibition of growth, indicating that activation of the NFkappaB signaling pathway was required for these processes. These results identify the NFkappaB-mediated signaling pathway and a target gene for MIS action and suggest a putative role for the MIS ligand and its downstream interactors in the treatment of ER-positive as well as negative breast cancers.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Mullerian inhibiting substance (MIS), a member of the transforming growth factor-β superfamily, induces regression of the Mullerian duct in male embryos. In this report, we demonstrate MIS type II receptor expression in normal breast tissue and in human breast cancer cell lines, breast fibroadenoma, and ductal adenocarcinomas. MIS inhibited the growth of both estrogen receptor (ER)-positive T47D and ER-negative MDA-MB-231 breast cancer cell lines, suggesting a broader range of target tissues for MIS action. Inhibition of growth was manifested by an increase in the fraction of cells in the G1 phase of the cell cycle and induction of apoptosis. Treatment of breast cancer cells with MIS activated the NFκB pathway and selectively up-regulated the immediate early gene IEX-1S, which, when overexpressed, inhibited breast cancer cell growth. Dominant negative IκBα expression ablated both MIS-mediated induction of IEX-1S and inhibition of growth, indicating that activation of the NFκB signaling pathway was required for these processes. These results identify the NFκB-mediated signaling pathway and a target gene for MIS action and suggest a putative role for the MIS ligand and its downstream interactors in the treatment of ER-positive as well as negative breast cancers.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Although PTP4A3 has been shown to be a very important factor in promoting cancer progression, the role of its close family member PTP4A2 is still largely unknown. Recent reports have shown contradicting results on the role of PTP4A2 in breast cancer progression. Considering this, we aimed to investigate the prognostic value of PTP4A2 in five independent breast cancer data sets (minimum 198 patients per cohort, totaling 1,124 patients) in the Gene Expression Omnibus Database. We found that high expression of PTP4A2 was a favorable prognostic marker in all five independent breast cancer data sets, as well as in the combined cohort, with a hazard ratio of 0.68 (95% confidence interval =0.56-0.83; P<0.001). Low PTP4A2 expression was associated with estrogen receptor-negative tumors and tumors with higher histological grading; furthermore, low expression was inversely correlated with the expression of genes involved in proliferation, including MKI67 and the MCM gene family encoding the minichromosome maintenance proteins. These findings suggest that PTP4A2 may play a role in breast cancer progression by dysregulating cell proliferation. PTP4A2 expression was positively correlated with ESR1, the gene encoding estrogen receptor-alpha, and inversely correlated with EGFR expression, suggesting that PTP4A2 may be involved in these two important oncogenic pathways. Together, our results suggest that expression of PTP4A2 is a favorable prognostic marker in breast cancer.