300 research outputs found
Determination of boundaries of cloudiness
Cloud boundary determinations based upon adiabatic flo
The Possibility of Emersion of the Outer Layers in a Massive Star Simultaneously with Iron-Core Collapse: A Hydrodynamic Model
We analyze the behavior of the outer envelope in a massive star during and
after the collapse of its iron core into a protoneutron star (PNS) in terms of
the equations of one-dimensional spherically symmetric ideal hydrodynamics. The
profiles obtained in the studies of the evolution of massive stars up to the
final stages of their existence, immediately before a supernova explosion
(Boyes et al. 1999), are used as the initial data for the distribution of
thermodynamic quantities in the envelope.We use a complex equation of state for
matter with allowances made for arbitrary electron degeneracy and relativity,
the appearance of electron-positron pairs, the presence of radiation, and the
possibility of iron nuclei dissociating into free nucleons and helium nuclei.
We performed calculations with the help of a numerical scheme based on
Godunov's method. These calculations allowed us to ascertain whether the
emersion of the outer envelope in a massive star is possible through the
following two mechanisms: first, the decrease in the gravitational mass of the
central PNS through neutrino-signal emission and, second, the effect of hot
nucleon bubbles, which are most likely formed in the PNS corona, on the
envelope emersion. We show that the second mechanism is highly efficient in the
range of acceptable masses of the nucleon bubbles ()
simulated in our hydrodynamic calculations in a rough, spherically symmetric
approximation.Comment: 14 pages, 11 figure
Childhood trauma fatality and resource allocation in injury control programs in a developing country
BACKGROUND: Only a few studies have addressed the trimodal distribution of childhood trauma fatalities in lesser developed countries. We conducted this study to evaluate pre-hospital, Emergency Department (ED) and in-hospital distribution of childhood injury-related death for each mechanism of injury in Tehran, Iran. This information will be used for the efficient allocation of the limited injury control resources in the city. METHODS: We used Tehran's Legal Medicine Organization (LMO) database. This is the largest and the most complete database that receives information about trauma fatalities from more than 100 small and large hospitals in Tehran. We reviewed all the medical records and legal documents of the deceased registered in LMO from September 1999 to September 2000. Demographic and injury related characteristics of the children 15 years old or younger were extracted from the records. RESULTS: Ten percent of the 4,233 trauma deaths registered in LMO occurred among children 15 years old or younger. Motor vehicle crashes (MVCs) (50%), burns (18%), falls (6%) and poisonings (6%) were the most common mechanisms of unintentional fatal injuries. Prehospital, emergency department and hospital deaths comprised 42%, 20% and 37% of the trauma fatalities, respectively. While, more than 80% of fatal injuries due to poisoning and drowning occurred in prehospital setting, 92% of burn-related fatalities happened after hospital admission. CONCLUSION: Injury prevention is the single most important solution for controlling trauma fatalities due to poisoning and drowning. Improvements in the quality of care in hospitals and intensive care units might substantially alleviate the magnitude of the problem due to burns. Improvements in prehospital and ED care might significantly decrease MVC and falls-related fatalities
Fine-mapping identifies multiple prostate cancer risk loci at 5p15, one of which associates with TERT expression
Associations between single nucleotide polymorphisms (SNPs) at 5p15 and multiple cancer types have been reported. We have previously shown evidence for a strong association between prostate cancer (PrCa) risk and rs2242652 at 5p15, intronic in the telomerase reverse transcriptase (TERT) gene that encodes TERT. To comprehensively evaluate the association between genetic variation across this region and PrCa, we performed a fine-mapping analysis by genotyping 134 SNPs using a custom Illumina iSelect array or Sequenom MassArray iPlex, followed by imputation of 1094 SNPs in 22 301 PrCa cases and 22 320 controls in The PRACTICAL consortium. Multiple stepwise logistic regression analysis identified four signals in the promoter or intronic regions of TERT that independently associated with PrCa risk. Gene expression analysis of normal prostate tissue showed evidence that SNPs within one of these regions also associated with TERT expression, providing a potential mechanism for predisposition to disease
Prostate cancer, treatment modalities and complications: an evaluation of the scientific literature
Prostate (PR) cancer (CA) is one of the most common malignant neoplasms in men all over the world. In general, if prostate cancer (PC) is detected early, treatment usually involves either surgical removal of the prostate or radiotherapy (RT). Hormone Therapy (HT) or chemotherapy (CH) is the preferred treatment for more advanced cases of PC or if CA spreads beyond the PT. A number of complications, such as urinary incontinence (IU) or erectile dysfunction (ED), can be associated with some modalities of treatment of the PC. The aim of this work is to evaluate, in PubMed, the number of publications related with prostate cancer and the main modalities of treatment, as well as some clinical complications. The searches were performed in PubMed (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi) in the period 1950 to 2008 using the words: (i) CA, (ii) CA and PR or penis or testis, (iii) CA and PR and RT, CA and PR and surgery (SU), CA and PR and CH and, CA and PR and HT and (iv) CA and PR and RT and IU or ED, CA and PR and SU and IU or ED, CA and PR and CH and IU or ED and, CA and PR and HT and CH and IU or ED, and (V) PC and the same modalities of treatment. The data was obtained on July 20th, 2008. PC, as expected has been cited extensively and surgery has been identified as the most widely referenced modality of treatment. Furthermore, urinary incontinence and erectile dysfunction are important complications that have attracted significant scientific interest. In conclusion, these findings have shown the relevance of the PubMed to analyze quantitatively the publications in cancer and this information could be worthwhile in aiding the comprehension of some clinical aspects related with PC, as well as the development of preventative actions. The analysis of the scientific interest, considering the number of publications in the PubMed, reveals research trends in the field and demonstrates the importance of the surgical procedures in the treatment of the prostate cancer. Moreover, this finding is relevant due to the fact that surgery is the treatment of choice when early detection of PC is achieved. However, it is important to consider clinical complications related to such procedures, such as urinary incontinence and erectile dysfunctions that can reduce the quality of life of the patient
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Abnormalities in Oxygen Sensing Define Early and Late Onset Preeclampsia as Distinct Pathologies
BACKGROUND:
The pathogenesis of preeclampsia, a serious pregnancy disorder, is still elusive and its treatment empirical. Hypoxia Inducible Factor-1 (HIF-1) is crucial for placental development and early detection of aberrant regulatory mechanisms of HIF-1 could impact on the diagnosis and management of preeclampsia. HIF-1α stability is controlled by O(2)-sensing enzymes including prolyl hydroxylases (PHDs), Factor Inhibiting HIF (FIH), and E3 ligases Seven In Absentia Homologues (SIAHs). Here we investigated early- (E-PE) and late-onset (L-PE) human preeclamptic placentae and their ability to sense changes in oxygen tension occurring during normal placental development.
METHODS AND FINDINGS:
Expression of PHD2, FIH and SIAHs were significantly down-regulated in E-PE compared to control and L-PE placentae, while HIF-1α levels were increased. PHD3 expression was increased due to decreased FIH levels as demonstrated by siRNA FIH knockdown experiments in trophoblastic JEG-3 cells. E-PE tissues had markedly diminished HIF-1α hydroxylation at proline residues 402 and 564 as assessed with monoclonal antibodies raised against hydroxylated HIF-1α P402 or P564, suggesting regulation by PHD2 and not PHD3. Culturing villous explants under varying oxygen tensions revealed that E-PE, but not L-PE, placentae were unable to regulate HIF-1α levels because PHD2, FIH and SIAHs did not sense a hypoxic environment.
CONCLUSION:
Disruption of oxygen sensing in E-PE vs. L-PE and control placentae is the first molecular evidence of the existence of two distinct preeclamptic diseases and the unique molecular O(2)-sensing signature of E-PE placentae may be of diagnostic value when assessing high risk pregnancies and their severity
Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas
This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing
molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin
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