4,562 research outputs found

    Adsorption Of No3--N And Po43--P in Aqueous Solution Using Granular Activated Charcoal (Gac)

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    In this study, adsorption of NO3- -N and PO43--P on granular activated charcoal (GAC) was investigated depending on pH, agitation time, GAC dosage, adsorption capacity and adsorption isotherms by employing batch adsorption type. The GAC was characterized by thermogravimetric analysis (TG-DTA), scanning electron micrograph coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) and BET surface area analyzer. The GAC exhibited nearly similar adsorption equilibrium time. Both NO3--N and PO43—P appeared to approach equilibrium after approximately 4 h of agitation time. In the adsorption equilibrium, the removal efficiencies of NO3- -N and PO43--P were found to be 14.6-66.0 % and 52.4-99.0 %, respectively. The adsorption data for NO3--N and PO43--P was correlated to Freundlich and Langmuir isotherm model and the equilibrium data was fitted well to the Langmuir isotherm model due to their higher correlation coefficient (R2) value. The Langmuir adsorption capacity was 1.54 and 2.56 mg g-1 for NO3--N and PO43--P, respectively, which suggests that the GAC is a good adsorbent for removal of NO3--N and PO43—P from water

    Comparison of Adsorptive Removal of Total Nitrogen (T-N) and Total Phosphorous (T-P) in Aqueous Solution using Granular Activated Charcoal (GAC)

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    The present study is to explore the possibility of utilizing granular activated charcoal (GAC) for the removal of total phosphorous (T-P) and total nitrogen (T-N) in aqueous solution. Batch adsorption studies were carried out to determine the influences of various factors like initial concentration, contact time and temperature. The adsorption data showed that GAC has a similar adsorption capacity for both T-N and T-P. The adsorption degree of T-N and T-P on GAC was highly concentration dependent. It was found that the adsorption capacity of GAC is quite favorable at a low concentration. At concentrations of 1.0 mg L-1 of T-P and 2.0 mg L-1 of T-N, approximately 97 % of adsorption was achieved by GAC. The equilibrium data were fitted well to the Langmuir isotherm model. The pseudo-second-order kinetic model appeared to be the better-fitting model because it has higher R2 compared with the pseudo-first-order and intra-particle kinetic model. The theoretical adsorption equilibrium qe,cal from pseudo-second-order kinetic model were relatively similar to the experimental adsorption equilibrium qe,exp. To evaluate the effect of thermodynamic parameters at different temperatures, the change in free energy ΔG, the enthalpy ΔH and the entropy ΔS were estimated. Except for adsorption of T-P at 278 K, the ΔG values obtained were all negative at the investigated temperatures. It indicates that the present adsorption system occurs spontaneously. The adsorption process of T-N by GAC was exothermic in nature, whereas T-P showed endothermic behavior. In addition, the positive values of ΔS imply that there was the increase in the randomness of adsorption of T-N and T-P at GAC-solution interface. Â

    Additional Listing Options on ebay: Are They Worth The Money

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    eBay is by far the world’s largest online auction site. Millions of people are doing transactions through it. eBay offers the sellers several additional listing options (“ALO” for short) at certain prices for them to enhance the visibility or attractiveness of their auction listings. In this paper we tried to find out how much these ALO can help to improve the outcome of an online auction, focusing mainly on the multiunit auctions of a certain brand of diet pill. The 116 data records were collected within a period of one month from the eBay’s “Diet and Weight loss” sub-category. In general, our idea can be applied to any other specific good sold on eBay. Our results provide important implications to eBay sellers in terms of deciding which ALO to use when listing his particular item for sale on eBay. Based on our findings, eBay or any auction sites could also apply our approach to estimate the optimal level of pricing of these ALO through computing the average value of the ALO for all transactions

    Inter- and Intra-Annual Variability of Vegetation in the Northern Hemisphere and Its Association with Precursory Meteorological Factors

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    Determination of phenological variation is one of the most critical challenges in dynamic vegetation modeling, given the lack of a strong theoretical framework. Previous studies generally focused on the timing of a phenological event (e.g., bud-burst or onset of growing season) and its atmospheric prompts, but not on the interactive variations across phenological stages. This study, therefore, investigated the inter- and intra-annual variability existing in all the phenological stages and the relations of the variability with four meteorological variables (surface temperature (Ts), shortwave radiation (SW ), vapor pressure deficit (VPD), and precipitation (PRCP)) using a 25-year (1982-2006) dataset of leaf area index (LAI) from the Advanced Very High Resolution Radiometer (AVHRR). Our six study sites of each 4 degree x 4 degree grids (mixed forest in China, deciduous needle-leaf forest in Siberia, evergreen needle-leaf forest in western Canada, grass in Gobi, and crops in the Central United States and southeastern Europe) include various vegetation types, local climates, and land-use types in the mid-latitudes of the northern hemisphere. Empirical orthogonal function (EOF) analysis with detrended LAI anomalies identified the two leading EOF modes that account for the amplitude and phase of the monthly LAI variations. The inter-annual correlation between the principle components (PCs) of the two modes and the meteorological variables for spring and summer showed that the amplitude and phase modes (AM and PM, respectively) were affected by different dominant meteorological factors. Over most of the study regions, AM was positively correlated with PRCP and negatively with Ts, SW, and VPD,while PMwas predominantly positively correlated with Ts. The contrasting responses of the two EOFmodes to Ts reflect environmental limitations on plant growth such as early start of growth, but with a reduced value of maximum LAI in a year with a warm spring. In addition, insignificant correlations between AMand PRCP, as well as negative correlations between PM and PRCP, in the crop regions suggest that human interventions such as advanced irrigation systems also play a key role in vegetative activity

    Analysis of Content Legibility for Smartphones of Websites of the Korean Urological Association and Other Urological Societies in Korea

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    Purpose: We performed an analysis of the smartphone legibility of the websites of the Korean Urological Association (KUA) and other urological societies. Materials and Methods: This study was conducted on the websites of the KUA and nine other urological societies. Each website was accessed via iPhone Safari and Android Chrome, respectively, to evaluate the establishment and readability of the mobile web pages. The provision of Really Simple Syndication (RSS) feeds by the websites and whether the websites had Twitter and Facebook accounts were evaluated. In addition, a validation test on the web standards was performed by using the World Wide Web Consortium (W3C???) Markup Validation Service, and subsequently the numbers of errors and warnings that occurred were analyzed. Results: When accessed via Safari, two websites were legible, four were somewhat legible, and four were somewhat illegible. When accessed via Chrome, two websites were legible, six were somewhat legible, and two were somewhat illegible. One website provided an RSS feed and two websites managed members via separate Twitter accounts. No website supported mobile web pages. The result of the W3C??? Markup Validation test on 10 websites showed a mean error rate of 221.6 (range, 13-1,477) and a mean warning rate of 127.13 (range, 0-655). Conclusions: The smartphone legibility level of the websites of urological societies was relatively low. Improved smartphone legibility and web standard compliance of the websites of urological societies are required to keep up with the popularity of smartphones

    Comparative effects of norepinephrine and vasopressin on internal thoracic arterial graft flow after off-pump coronary artery bypass grafting

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    ObjectiveVasoconstrictors such as norepinephrine and vasopressin are commonly used to raise the blood pressure during myocardial revascularization. The internal thoracic artery is commonly used for coronary artery grafting because of its long-term patency. However, the internal thoracic artery is a living conduit that responds to vasoactive substances. The objective of this study was to measure change in internal thoracic arterial flow after infusion of norepinephrine or vasopressin.MethodsForty-one patients undergoing elective off-pump coronary artery bypass grafting participated in this study. After the median sternotomy, the left internal thoracic artery was dissected with a pedicle and grafted to the left anterior descending artery. After all anastomoses were performed and hemodynamic parameters were stable, the grafted internal thoracic arterial blood flow was measured by transit time flowmeter on the distal portion of the graft as a baseline. Norepinephrine or vasopressin was then infused until mean arterial pressure was increased to 20% of baseline. Graft flow and hemodynamic variables were measured when mean arterial pressure reached the intended level.ResultsBaseline grafted internal thoracic arterial flows were similar (norepinephrine 57.1 ± 17.7 mL min−1, vasopressin 66.0 ± 34.3 mL min−1). With norepinephrine, flow increased significantly relative to baseline (77.2 ± 31.0 mL min−1); with vasopressin, it remained unchanged (68.3 ± 37.0 mL min−1).ConclusionsFor patients needing vasopressor support after coronary artery bypass grafting, norepinephrine appeared superior to vasopressin because of increased internal thoracic arterial flow

    Whole-liver radiotherapy for end-stage colorectal cancer patients with massive liver metastases and advanced hepatic dysfunction

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    <p>Abstract</p> <p>Background</p> <p>To investigate whether whole-liver radiotherapy (RT) is beneficial in end-stage colorectal cancer with massive liver metastases and severe hepatic dysfunction.</p> <p>Methods</p> <p>Between June 2004 and July 2008, 10 colorectal cancer patients, who exhibited a replacement of over three quarters of their normal liver by metastatic tumors and were of Child-Pugh class B or C in liver function with progressive disease after undergoing chemotherapy, underwent whole-liver RT. RT was administered using computed tomography-based three-dimensional planning and the median dose was 21 Gy (range, 21-30) in seven fractions. Improvement in liver function tests, defined as a decrease in the levels within 1 month after RT, symptom palliation, toxicity, and overall survival were analyzed retrospectively.</p> <p>Results</p> <p>Levels of alkaline phosphatase, total bilirubin, aspartate transaminase, and alanine transaminase improved in 8, 6, 9, and all 10 patients, respectively, and the median reduction rates were 42%, 68%, 50%, and 57%, respectively. Serum carcinoembryonic antigen level decreased after RT in three of four assessable patients. For all patients, pain levels decreased and acute toxicity consisted of nausea/vomiting of grade ≤ 2. Further chemotherapy became possible in four of 10 patients. Mean survival after RT was 80 ± 80 days (range, 20-289); mean survival for four patients who received post-RT chemotherapy was 143 ± 100 days (range, 65-289), versus 38 ± 16 days (range, 20-64) for the six patients who did not receive post-RT chemotherapy (<it>p </it>= 0.127).</p> <p>Conclusions</p> <p>Although limited by small case number, this study demonstrated a possible role of whole-liver RT in improving hepatic dysfunction and delaying mortality from hepatic failure for end-stage colorectal cancer patients with massive liver metastases. Further studies should be followed to confirm these findings.</p
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