373 research outputs found

    Intrinsic anomalous Hall effect in nickel: An GGA+U study

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    The electronic structure and intrinsic anomalous Hall conductivity of nickel have been calculated based on the generalized gradient approximation (GGA) plus on-site Coulomb interaction (GGA+U) scheme. It is found that the intrinsic anomalous Hall conductivity (σxyH\sigma_{xy}^H) obtained from the GGA+U calculations with U=1.9U = 1.9 eV and J=1.2J=1.2 eV, is in nearly perfect agreement with that measured recently at low temperatures while, in contrast, the σxyH\sigma_{xy}^H from the GGA calculations is about 100% larger than the measured one. This indicates that, as for the other spin-orbit interaction (SOI)-induced phenomena in 3dd itinerant magnets such as the orbital magnetic magnetization and magnetocrystalline anisotropy, the on-site electron-electron correlation, though moderate only, should be taken into account properly in order to get the correct anomalous Hall conductivity. The intrinsic σxyH\sigma_{xy}^H and the number of valence electrons (NeN_e) have also been calculated as a function of the Fermi energy (EFE_F). A sign change is predicted at EF=0.38E_F = -0.38 eV (Ne=9.57N_e = 9.57), and this explain qualitatively why the theoretical and experimental σxyH\sigma_{xy}^H values for Fe and Co are positive. It is also predicted that fcc Ni(1x)_{(1-x)}Co(Fe,Cu)x_x alloys with xx being small, would also have the negative σxyH\sigma_{xy}^H with the magnitude being in the range of 5001400500\sim 1400 Ω1\Omega^{-1}cm1^{-1}. The most pronounced effect of including the on-site Coulomb interaction is that all the dd-dominant bands are lowered in energy relative to the EFE_F by about 0.3 eV, and consequently, the small minority spin X2_2 hole pocket disappears. The presence of the small X2_2 hole pocket in the GGA calculations is attributed to be responsible for the large discrepancy in the σxyH\sigma_{xy}^H between theory and experiment.Comment: 7 pages, 3 figures; Accepted for publication in Physical Review

    AXL modulates extracellular matrix protein expression and is essential for invasion and metastasis in endometrial cancer

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    The receptor tyrosine kinase AXL promotes migration, invasion, and metastasis. Here, we evaluated the role of AXL in endometrial cancer. High immunohistochemical expression of AXL was found in 76% (63/83) of advanced-stage, and 77% (82/107) of high-grade specimens and correlated with worse survival in uterine serous cancer patients. In vitro, genetic silencing of AXL inhibited migration and invasion but had no effect on proliferation of ARK1 endometrial cancer cells. AXL-deficient cells showed significantly decreased expression of phospho-AKT as well as uPA, MMP-1, MMP-2, MMP-3, and MMP-9. In a xenograft model of human uterine serous carcinoma with AXL-deficient ARK1 cells, there was significantly less tumor burden than xenografts with control ARK1 cells. Together, these findings underscore the therapeutic potentials of AXL as a candidate target for treatment of metastatic endometrial cancer

    Radiation therapy for vaginal and perirectal lesions in recurrent ovarian cancer

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    The role for localized radiation to treat ovarian cancer (OC) patients with locally recurrent vaginal/perirectal lesions remains unclear, though we hypothesize these patients may be salvaged locally and gain long-term survival benefit. We describe our institutional outcomes using intensity modulated radiation therapy (IMRT) +/- high-dose rate (HDR) brachytherapy to treat this population. Our primary objectives were to evaluate complete response rates of targeted lesions after radiation and calculate our 5-year in-field control (IFC) rate. Secondary objectives were to assess radiation-related toxicities, chemotherapy free-interval (CFI), as well as post-radiation progression-free (PFS) and overall survival (OS). PFS and OS were defined from radiation start to either progression or death/last follow-up, respectively. This was a heavily pre-treated cohort of 17 recurrent OC patients with a median follow-up of 28.4 months (range 4.5-166.4) after radiation completion. 52.9% had high-grade serous histology and 4 (23.5%) had isolated vaginal/perirectal disease. Four (23.5%) patients had in-field failures at 3.7, 11.2, 24.5, and 27.5 months after start of radiation, all treated with definitive dosing of radiation therapy. Patients who were platinum-sensitive prior to radiation had similar median PFS (6.5 vs. 13.4 months, log-rank p = 0.75), but longer OS (71.1 vs 18.8 months, log-rank p = 0.05) than their platinum-resistant counterparts. Excluding patients with low-grade histology or who were treated with palliative radiation, median CFI was 14.2 months (range 4.7 - 33.0). Radiation was well tolerated with 2 (12.0%) experiencing grade 3/4 gastrointestinal/genitourinary toxicities. In conclusion, radiation to treat locally recurrent vaginal/perirectal lesions in heavily pre-treated OC patients is safe and may effectively provide IFC

    Methods and apparatus for constructing and implementing a universal extension module for processing objects in a database

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    Methods and apparatus for providing a multi-tier object-relational database architecture are disclosed. In one illustrative embodiment of the present invention, a multi-tier database architecture comprises an object-relational database engine as a top tier, one or more domain-specific extension modules as a bottom tier, and one or more universal extension modules as a middle tier. The individual extension modules of the bottom tier operationally connect with the one or more universal extension modules which, themselves, operationally connect with the database engine. The domain-specific extension modules preferably provide such functions as search, index, and retrieval services of images, video, audio, time series, web pages, text, XML, spatial data, etc. The domain-specific extension modules may include one or more IBM DB2 extenders, Oracle data cartridges and/or Informix datablades, although other domain-specific extension modules may be used

    Period, birth cohort and prevalence of dementia in mainland China, Hong Kong and Taiwan: a meta-analysis.

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    OBJECTIVE: There have been dramatic societal changes in East Asia over the last hundred years. Several of the established risk factors could have important period and cohort effects. This study explores temporal variation of dementia prevalence in mainland China, Hong Kong and Taiwan taking study methods into account. METHODS: Seventy prevalence studies of dementia in mainland China, Hong Kong and Taiwan were identified from 1980 to 2012. Five period groups (before 1990, 1990 ~ 1994, 1995 ~ 1999, 2000 ~ 2004 and 2005 ~ 2012) and five birth cohort groups (1895 ~ 1909, 1910 ~ 1919, 1920 ~ 1929, 1930 ~ 1939 and 1940 ~ 1950) were categorised using the year of investigation and 5-year age groups. Pooled prevalence by age, period and birth cohort groups was estimated through meta-regression model and meta-analysis taking diagnostic criteria and age structure into account. RESULTS: After adjusting for diagnostic criteria, the study age range and age structure, the prevalence of dementia in the older population aged 60 years and over fluctuated across periods but not reaching significance and were estimated as 1.8%, 2.5%, 2.1%, 2.4% and 3.1% for the five periods from pre-1990 to 2005 ~ 2012. A potential increasing pattern from less to more recent birth cohort groups was found in the major studies using older diagnostic criteria with wider differences in the age groups over 70 years. CONCLUSIONS: This study found no significant variation across periods but suggested a potential cohort effect. The influence of societal changes might moderate early life experiences across different generations with substantial impact on mental health in older age.There is no specific funding contributing to this study. Yu-Tzu Wu received a PhD scholarship from the Cambridge Trust, University of Cambridge. Fiona E. Matthews and A. Matthew Prina were supported by the Medical Research Council [grand number U105292687 and MR/K021907/1]This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/gps.414

    Community access to primary care is an important geographic disparity among ovarian cancer patients undergoing cytoreductive surgery

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    OBJECTIVE: Given the importance of understanding neighborhood context and geographic access to care on individual health outcomes, we sought to investigate the association of community primary care (PC) access on postoperative outcomes and survival in ovarian cancer patients. METHODS: This was a retrospective cohort study of Stage III-IV ovarian cancer patients who underwent surgery at a single academic, tertiary care hospital between 2012 and 2015. PC access was determined using a Health Resources and Services Administration designation. Outcomes included 30-day surgical and medical complications, extended hospital stay, ICU admission, hospital readmission, progression-free and overall survival. Descriptive statistics and chi-squared analyses were used to analyze differences between patients from PC-shortage vs not PC-shortage areas. RESULTS: Among 217 ovarian cancer patients, 54.4 % lived in PC-shortage areas. They were more likely to have Medicaid or no insurance and live in rural areas with higher poverty rates, significantly further from the treating cancer center and its affiliated hospital. Nevertheless, 49.2 % of patients from PC-shortage areas lived in urban communities. Residing in a PC-shortage area was not associated with increased surgical or medical complications, ICU admission, or hospital readmission, but was linked to more frequent prolonged hospitalization (26.3 % vs 14.1 %, p = 0.04). PC-shortage did not impact progression-free or overall survival. CONCLUSIONS: Patients from PC-shortage areas may require longer inpatient perioperative care in order to achieve the same 30-day postoperative outcomes as patients who live in non-PC shortage areas. Community access to PC is a critical factor to better understanding and reducing disparities among ovarian cancer patients

    Genetic characterization of primary and metastatic high-grade serous ovarian cancer tumors reveals distinct features associated with survival

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    High-grade serous ovarian cancer (HGSC) is the most lethal histotype of ovarian cancer and the majority of cases present with metastasis and late-stage disease. Over the last few decades, the overall survival for patients has not significantly improved, and there are limited targeted treatment options. We aimed to better characterize the distinctions between primary and metastatic tumors based on short- or long-term survival. We characterized 39 matched primary and metastatic tumors by whole exome and RNA sequencing. Of these, 23 were short-term (ST) survivors (overall survival (OS) \u3c 3.5 years) and 16 were long-term (LT) survivors (OS \u3e 5 years). We compared somatic mutations, copy number alterations, mutational burden, differential gene expression, immune cell infiltration, and gene fusion predictions between the primary and metastatic tumors and between ST and LT survivor cohorts. There were few differences in RNA expression between paired primary and metastatic tumors, but significant differences between the transcriptomes of LT and ST survivors in both their primary and metastatic tumors. These findings will improve the understanding of the genetic variation in HGSC that exist between patients with different prognoses and better inform treatments by identifying new targets for drug development

    The treatment and outcomes of early-stage epithelial ovarian cancer: have we made any progress?

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    The objective of this study is to determine the progress and trends in the treatment and survival of women with early-stage (I–II) epithelial ovarian cancer. Data were obtained from the SEER database between 1988 and 2001. Kaplan–Meier and Cox regressions methods were employed for statistical analyses. Of the 8372 patients, the median age was 57 years (range: 12–99 years). A total of 6152 patients (73.4%) presented with stage I and 2220 (26.5%) with stage II disease. Over the periods 1988–1992, 1993–1997, and 1998–2001, 3-year disease-specific survivals increased from 86.1 to 87.2 to 88.8% (P=0.076). The number of patients that underwent lymphadenectomy has increased significantly from 26.2 to 38.7 to 54.2% over the study period (P<0.001). Of those patients who underwent staging procedures with lymphadenectomy, there was no improvement in survival over the three study periods (from 93.2 to 93.5 to 93.1%; P=0.978). On multivariate analysis, younger age, nonclear cell histology, earlier stage, lower grade, surgery, and lymphadenectomy were significant independent prognostic factors for improved survival. After adjusting for surgical staging with lymphadenectomy, the year of diagnosis was no longer an important prognostic factor. In conclusion, the use of lymphadenectomy during surgery for early-stage ovarian cancer has doubled over the last 14 years. The marginal improvement in survival demonstrated over time is potentially attributed to the increased use of staging procedures with lymphadenectomy
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