233 research outputs found

    Helical Packings and Phase Transformations of Soft Spheres in Cylinders

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    The phase behavior of helical packings of thermoresponsive microspheres inside glass capillaries is studied as a function of volume fraction. Stable packings with long-range orientational order appear to evolve abruptly to disordered states as particle volume fraction is reduced, consistent with recent hard sphere simulations. We quantify this transition using correlations and susceptibilities of the orientational order parameter psi_6. The emergence of coexisting metastable packings, as well as coexisting ordered and disordered states, is also observed. These findings support the notion of phase transition-like behavior in quasi-1D systems.Comment: 5 pages, with additional 4 pages of supplemental material, accepted to Physical Review E: Rapid Communication

    A Machine-Learning-Based Approach to Predict the Health Impacts of Commuting in Large Cities: Case Study of London

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    The daily commute represents a source of chronic stress that is positively correlated with physiological consequences, including increased blood pressure, heart rate, fatigue, and other negative mental and physical health effects. The purpose of this research is to investigate and predict the physiological effects of commuting in Greater London on the human body based on machine-learning approaches. For each participant, the data were collected for five consecutive working days, before and after the commute, using non-invasive wearable biosensor technology. Multimodal behaviour, analysis and synthesis are the subjects of major efforts in computing field to realise the successful human–human and human–agent interactions, especially for developing future intuitive technologies. Current analysis approaches still focus on individuals, while we are considering methodologies addressing groups as a whole. This research paper employs a pool of machine-learning approaches to predict and analyse the effect of commuting objectively. Comprehensive experimentation has been carried out to choose the best algorithmic structure that suit the problem in question. The results from this study suggest that whether the commuting period was short or long, all objective bio-signals (heat rate and blood pressure) were higher post-commute than pre-commute. In addition, the results match both the subjective evaluation obtained from the Positive and Negative Affect Schedule and the proposed objective evaluation of this study in relation to the correlation between the effect of commuting on bio-signals. Our findings provide further support for shorter commutes and using the healthier or active modes of transportation

    Melting of Colloidal Crystal Films

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    Effect of SPIO Nanoparticle Concentrations on Temperature Changes for Hyperthermia via MRI

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    Magnetic nanoparticles (MNPs) are being developed for a wide range of biomedical applications. In particular, hyperthermia involves heating the MNPs through exposure to an alternating magnetic field (AMF). These materials offer the potential for selectively by heating cancer tissue locally and at the cellular level. This may be a successful method if there are enough particles in a tumor possessing sufficiently high specific absorption rate (SAR) to deposit heat quickly while minimizing thermal damage to surrounding tissue. The current research aim is to study the influence of super paramagnetic iron oxides Fe3O4 (SPIO) NPs concentration on the total heat energy dose and the rate of temperature change in AMF to induce hyperthermia in Ehrlich carcinoma cells implanted in female mice. The results demonstrated a linearly increasing trend between these two factors

    Length-weight relationships and relative condition factor of Parapenaeopsis sculptilis (Heller, 1862) from the coastal waters of Perak, Peninsular Malaysia

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    Length-weight relationship (LWR) parameters and relative condition factor (K n) of marine shrimp, Parapenaeopsis sculptilis (Heller, 1862) were estimated using length-weight data collected between February 2012 and January 2013 from the coastal waters of Terong, Perak, Peninsular Malaysia. The estimated length-weight relationship of P. sculptilis for both sexes was W = 0.00027TL2.80. Meanwhile, the estimated relative growth coefficient (b) was 2.80 for both sexes, indicating a negative allometric growth pattern of P. sculptilis in the investigated area. Relative condition factor (Kn) values ranged from 0.99 to 1.064 (1.013±0.005, mean ±SD). Kn value changes in various months: the highest peak was in March-April, indicating the spawning period and the trough and small peaks indicating the cycle gonadal development

    Population dynamics of sergestid shrimps Acetes japonicus in the estuary of Tanjung Dawai, Kedah, Malaysia

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    Population parameters of male and female A. japonicus were studied using the monthly length frequency data to evaluate the mortality rates and its exploitation level. The sex ratio (male: Female) was found at 1: 0.94. Asymptotic length (L∞) was 25.20 mm and 28.88 mm for male and female, respectively. Growth co-efficient (K) for males and females was estimated at 1.80 and 1.30 year-1, respectively. Total mortality (Z) was calculated at 5.98 and 4.44 year-1 for male and female of A. japonicus respectively. Natural mortality (M) was 2.82 and 2.19 year-1 for the male and female shrimps. The fishing mortality (F) was 3.16 year-1 for male and 2.25 year-1 for female. Exploitation level (E) for male and female of A. japonicus was calculated at 0.53 and 0.51. The exploitation level was slightly over (E>0.50) the optimum level of exploitation (p = 0.50). The stock of A. japonicus was found to be slightly over exploited in Tanjung Dawai estuarine waters

    Particle dynamics in colloidal suspensions above and below the glass-liquid re-entrance transition

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    We study colloidal particle dynamics of a model glass system using confocal and fluorescence microscopy as the sample evolves from a hard-sphere glass to a liquid with attractive interparticle interactions. The transition from hard-sphere glass to attractive liquid is induced by short-range depletion forces. The development of liquid-like structure is indicated by particle dynamics. We identify particles which exhibit substantial motional events and characterize the transition using the properties of these motional events. As samples enter the attractive liquid region, particle speed during these motional events increases by about one order of magnitude, and the particles move more cooperatively. Interestingly, colloidal particles in the attractive liquid phase do not exhibit significantly larger displacements than particles in the hard-sphere glass

    Oral thearubigins do not protect against acetaminopheninduced hepatotoxicity in mice

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    Purpose: To investigate the potential protective effect of oral repeated doses of thearubigins against acetaminophen-induced hepatotoxicity in mice.Methods: Mice were randomly divided into six groups (n=8) and administered the following: Control group (saline), acetaminophen group (saline), N-acetylcysteine group (500 mg/kg/day), and thearubigins groups (60, 70, 100 mg/kg/day). The drugs were given orally by gavage for seven days. On day 7, 1 h after the last dose of treatment, the mice (except control group) were given a single dose of acetaminophen (n-acetyl-p-aminophenol, APAP) orally by gavage (350 mg/kg) and then sacrificed 4 h post-APAP intake. Blood was collected for biochemical measurements and their liver were subjected to biochemical and histopathological assessment.Results: The acetaminophen group showed significant increases (p < 0.001) in serum alanine aminotransferase level, hepatic cytochrome P2E1 level, and serum and hepatic malondialdehyde levels. Moreover it showed significant decrease (p < 0.001) in serum and hepatic glutathione levels. Morphologically, the liver sections showed cellular necrosis, vacuolization, and degeneration around the centrilobular veins. Pretreatment with N-acetylcysteine reversed all acetaminophen-induced changes (p < 0.001 for all biomarkers except for hepatic MDA (p = 0.014) while pretreatment with thearubigins failed to reverse any of them.Conclusion: Oral repeated doses of thearubigins failed to protect against acetaminophen-induced hepatotoxicity in mice and didn't affect hepatic cytochrome P2E1 level.Keywords: Acetaminophen, Hepatotoxicity, Thearubigins, N-acetylcysteine, Cellular necrosis, Vacuolization, Hepatic cytochrome P2E

    Quantile Regression to Tackle the Heterogeneity on the Relationship Between Economic Growth, Energy Consumption, and CO2 Emissions

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    Heterogeneity in the data is a common issue arising in research. When data are heterogeneous, equal variation in the data to set up a model for the studied phenomena cannot be assumed. Ordinary least square regression does not consider the unequal variation which may provide inefficient estimation of the relationship between variables. On the contrary, quantile regression could efficiently tackle this problem by detecting the relationship between variables at different levels, and could be useful especially in applications where extreme values are important to consider, such as in environmental studies, where upper quantiles of pollution levels are critical from a public health perspective. The main purpose of this study is to model the relationship between CO2, economic growth, and energy consumption by considering the heterogeneity problem for developed and developing countries and applying the quantile regression at different percentile values (0.05, 0.25, 0.50, 0.75, and 0.95) on panel data. The panel data consists of 29 countries from two different economic development groups: 17 developed versus 12 developing countries\u2014over the period 1960\u20132008. Quantile regression (QR) results are then compared with those of the OLS model, resulting similar for developed and developing countries. In both cases, countries having lower GDP release less CO2 emissions

    Dose verification of intensity modulated radiotherapy in head and neck tumors

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    Purpose: To evaluate the agreement between measured and calculated doses for head and neck tumors using different gamma criteria and to establish quality assurance protocol for the delivery of IMRT in The National Cancer Institute in Cairo. Methods: The dose is calculated for 30 patients using CMS Treatment Planning System. The ionization chamber (0.6 cm3 Farmer type) is used for point dose measurements. The 2D-array (PTW 729) and GafChromic films (EBT2) are used for 2D graphical dose distribution. Four different gamma criteria of dose difference (DD) and distance to agreement (DTA) (3%/3 mm, 3%/5 mm, 4%/4 mm and 5%/5 mm DD / DTA) are selected. These criteria are evaluated while suppressing the dose of 10%, 20% or 30% from dose distribution. Results: Point dose evaluations using the ion chamber ranged from -2.6% to 3.7% (mean and standard deviation of 0.46 ± 1.7). Significant differences are observed between the films and 2D-array for all criteria except the 3%/5 mm criteria (96.89 ± 2.2% vs. 94.81 ± 4.2% (p < 0.01)). Conclusion: Differences may exceed about 3% when the ionization chamber is present in steep dose gradient regions. The present results suggest the gamma criteria of 3%/5 mm as the most suitable criteria for IMRT quality assurance. This gamma criterion of 3%/5 mm favorably exceeds 95% in case of maximum dose while suppressing the dose of 20%.The use of 2D-array can reduce the IMRT QA workload.------------------------------Cite this article as: Elawady RA, Attalla EM, Elshemey WM, Shouman T, Alsayed AA. Dose verification of intensity modulated radiotherapy in head and neck tumors. Int J Cancer Ther Oncol 2014; 2(3):02037. DOI: 10.14319/ijcto.0203.
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