375 research outputs found

    Power spectrum characterization of systematic coded UW-OFDM systems

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    Unique word (UW)-OFDM is a newly proposed multicarrier technique that has shown to outperform cyclic prefix (CP)-OFDM in fading channels. Until now, the spectrum of UW-OFDM is not thoroughly investigated. In this paper, we derive an analytical expression for the spectrum taking into account the DFT based implementation of the system. Simulations show that the proposed analytical results are very accurate. Compared to CP-OFDM, we show that UW-OFDM has much lower out-of-band (OOB) radiation, which makes it suitable for systems with strict spectral masks, as e. g. cognitive radios. Further, in this paper, we evaluate the effect of the redundant carrier placement on the spectrum

    Gamma radiation-induced impairment of hippocampal neurogenesis, comparison of single and fractionated dose regimens Deterioro de la neurogénesis en el hipocampo inducida por radiación gamma, comparación de los regímenes de dosis única y fraccionada

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    Radiation therapy of the brain is associated with many consequences, including cognitive disorders. Pathogenesis of radiation induced cognitive disorder is not clear, but reduction of neurogenesis in hippocampus may be an underlying reason. 24 adult male rats entered to study. Radiation absorbed dose to midbrain was 10 Gy, delivered by routine cobalt radiotherapy machine which its output was measured 115.24 cGy/min. The rats were divided in four groups of sixes, including groups of control, single fraction 10 Gy, fractionated 10 Gy and finally anaesthesia sham group. Number of pyramidal nerve cells was counted in two regions of hippocampus formation (CA1 and CA3). The radiation could reduce the number of cells in two regions of hippocampus significantly (p=0.000). It seems fractionated 10 Gy irradiation to more efficient than single fraction, while role of anaesthesia drug should be cautiously assessed. Moreover the rate of neurogenesis reduction was determined the same in these regions of hippocampus meaning the same radiosensitivity of cells

    The Hidden War: Injustice in the Wake of the Philippine-American War

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    This thesis describes the United States’ campaign in the Philippines and the atrocities that occurred there and tells the story of how those atrocities were hidden, marginalized, and forgotten in the years after the war. I will show how this was not a natural process, that the Philippine-American war was not passively misunderstood or forgotten. Instead, I will show how misinformation and the suppression of the truth was an orchestrated effort by imperialist politicians and military officials to control the narrative, justify their decisions and protect their policies. Specifically, this thesis will analyze the hearings before the Committee on the Philippines, which was tasked with investigating the reports of atrocities, as well as the military courts-martial after the war. Analysis of that bias and partisanship reveals that the hearings were more of a vindication than an investigation, and the courts-martial were more of a search for an excuse than a search for justice. This thesis will explain the precedents of military misconduct and political manipulation that were established by how United States politicians and military officials dealt with the atrocities that occurred during one of the United States’ first overseas imperialist occupations.Ope

    Quality assurance program for prototype stereotactic system developed for Neptun 10 PC linac

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    Background: A prototype stereotactic radiosurgery set was designed and constructed for a Neptun 10 PC linac that is currently being used at Imam Reza hospital in Mashhad. Materials and Methods: A complete qualit y assurance program was designed and performed for the constructed system including isocentric accuracy test, localization accuracy test, dose delivery accuracy test and leakage radiation test. Target simulator, control alignment device and plexiglass phantom which were parts of the developed hardware were used to fulfill quality assurance program. Results: The average isocentric shift resulted from the gantry rotation and couch turning were respectively obtained to be 1.4 and 2 mm. The average localization error in the three coordinates was found to be 2.2 mm. The total treatment uncertainty due to all of the probable errors in the system was equal to 4.32 mm. The dose delivery accuracy test was carried out, the result indicated a 3-7% difference between the given and measured dose. Conclusion: The quality assurance tests showed consistent performance of the constructed system within the accepted limits; however, some inconsistency might exist in certain cases. The safety of SRS method is increased when the overall uncertainty is minimized and the treatment of the lesions adjacent to critical organs is avoided

    Attribution of ghrelin to cancer; Attempts to unravel an apparent controversy

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    Ghrelin is an endogenous peptide hormone mainly produced in the stomach. It has been known to regulate energy homeostasis, stimulate secretion of growth hormone, and mediate many other physiologic effects. Various effects attributed to ghrelin contribute to many aspects of cancer development and progression. Accordingly, a large body of evidence has emerged about the association of ghrelin with several types of cancer in scales of cell-line, animal, and human studies. However, existing data are controversial. This controversy occurs in two main domains: one is the controversial results in local effects of ghrelin on different types of human cancer cell-lines; the second is the apparent disagreement in the results o

    Comparing the Conventional with Low Dose of Bupivacaine Plus Fentanyl in Spinal Anesthesia on the Neonate Apgar Score in Yazd City

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    Introduction: Spinal anesthesia is the preferred method of anesthesia in cesarean section, due to less complications. The augmentation of opioids to spinal anesthetics can improve the quality and increase the duration of analgesia. This study aimed to compare the conventional with low dose of bupivacaine plus fentanyl in spinal anesthesia on the neonate Apgar score in elective cesarean section. Methods: The present double-blind randomized clinical trial was conducted on 150 pregnant mothers undergoing cesarean section with the spinal anesthesia during 2017-2018. The mothers were randomly assigned to two groups of 75. The spinal anesthesia was performed in the first group with the injection of 15 mg of 0.5% hyperbaric bupivacaine plus 1 ml of normal saline, and in the second group with the injection of 12.5 mg of 0.5% hyperbaric bupivacaine plus 25 ÎĽg of fentanyl. For both groups, 1- and 5-minute neonatal Apgar scores were assessed. Finally, the data were analyzed by SPSS17 software using statistical tests. Results: The mean age of the samples was 30.1±5.19 years with a range of 18-42 years (P-value=0.246). The mean gestational age was 38 weeks, the mean 1-minute Apgar score was 8.88 and the mean 5-minute Apgar score was 9.89. Conclusion: With the augmentation of fentanyl to bupivacaine for spinal anesthesia, the conventional dose can be reduced, which not only reduces the common side effects of Marcainee, but also provides an appropriate level of anesthesia and does not affect the neonatal Apgar score

    The effect of radiotherapy and chemotherapy on osmotic fragility of red blood cells and plasma levels of malondialdehyde in patients with breast cancer

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    Background: Gamma radiation effects on the erythrocyte membrane from three different functional parts, lipid bilayer, cytoskeleton and protein components. When the red cell membrane is exposed to radiation, it loses its integrity and hemoglobin leaks out. In addition, irradiation leads to lipid peroxidation and the products of this process, leading to hemolysis. The aim of the present study was to measure osmotic fragility (OF) of red blood cells and malondialdehyde (MDA) levels as a marker of oxidative injury in breast cancer patients treated with radiation and chemotherapy. Materials and Methods: The OF test was performed using different concentrations of a salt solution. The measurement of MDA was done with chemical methods.11 The sampling was taken during three stages of treatment: first sample was taken before starting chemotherapy, the second sample was taken before radiation therapy and the third sample was taken after radiotherapy. Results: No statistically significant differences between levels of MDA in these three stages of treatment were observed. However, the comparison of mean levels of MDA showed an increase after radiotherapy. The OF rate did not show significant difference (P > 0.05) during the stages of treatment. Conclusion: In a standard treatment program of radiotherapy and chemotherapy lipid peroxidation level and OF do not significantly increase. © 2014 Greater Poland Cancer Centre

    Multiple-access interference rejecting receivers in DS-CDMA communication system

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    SIGLEAvailable from British Library Document Supply Centre-DSC:DXN037068 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    Self Portrait With Dr. Arrieta and the Medical Profession's Tenuous Status in the Public Eye

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    cientes (1746–1828) bridge the gulf in many ways, from the 18th-century Euro-pean masters to the early seeds of mod-ernism. In the wake of the revolution to the north and the Napoleonic Wars dur-ing his lifetime, tumultuous political and social upheavals in Spain impacted the artist, directly. Goya’s artistic opus transi-tioned from that of the celebrated chief court painter for King Charles IV (later shunned by his successor, Ferdinand VII) to his elderly personal works, fo-cused on common life scenes, popular events, and depictions of “capricious sub-jects ” (witches, ghosts, and monsters)

    Assessment of two emergency contraceptive regimens in Iran: Levonorgestrel versus the Yuzpe

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    The purpose of this study was to compare the efficacy and tolerability of two emergency contraception (EC)methods, levonorgestrel versus theYuzpe. In a prospective, randomized, comparative study, we included 122 healthy volunteers who in the observed cycle had had only one act of unprotected intercourse within 72h of treatment. They were randomlyallocated in levonorgestrol group (n=62) andYuzpe (n=60).The levonorgestrel regimen consisted of two pills: 0.75 mg levonorgestrel, taken twice in the 12-h interval within 72h after unprotected intercourse. The Yuzpe method included twoHDcontraceptive pills taken as another regimen.Datawere collected by questionnaire at first and 3weeks later.The differenceswere comparedwithX &Fisher exact tests. There were no significant differences between two groups in any of the observed parameters. The levonorgestrel regimen was found superior to Yuzpe because it's more effectiveness (respectively 100% vs 91%, p=0.026) and fewer side effects. The study showed more effectiveness and safety of the levonorgestrel regimen as emergency contraception. Thus we recommend levonorgestrel as an alternative EC method instead of theYuzpe regimen in Iran or other developing countries in order to decrease unwanted pregnancy.Keywords: Yuzpe, Levonorgestrel, emergency contraceptio
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