266 research outputs found
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Sequential low-temperature depolymerization and liquefaction of US coals
Results obtained in the studies with BS(IL) coal as feed can be summarized as follows: (1) The low-temperature depolymerization - liquefaction procedure, summarized in Figure 1, is easily adaptable and applicable to a high-sulfur, Burning Star (Illinois No. 6) coal sample. The final product obtained consists of a fully desulfurized, light hydrocarbon oil. (2)Suitable processing conditions for each step of the stepwise depolymerization - liquefaction of the above coal were determined. (3)Direct hydroprocessing of the Burning Star (Illinois No. 6) coal with sulfided catalysts is ineffective for its conversion into a light hydrocarbon product. In accordance with the research program the depolymerized, THF-soluble coal products will be subjected to detailed analysis for the purpose of deriving average molecular structures for the oil, asphaltene and asphaltol fractions. The data obtained will be used to develop a structural model for the BS(IL) coal
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Sequential low-temperature depolymerization and liquefaction of US coals
A Beulah-Zap (North Dakota) lignite sample, designated below as BZ(ND) lignite, was obtained from the Argonne National Laboratory premium coal program. This lignite had the following ultimate analysis (MAF basis) in wt.%: C, 71.05; H, 5.58; N, 1.17; S, 1.60; 0 (diff), 20.6. The ash content (dry basis) was 6.0 wt.%. As expected, the BZ(ND) lignite had a considerably higher oxygen content ([approximately]20.6%) in comparison with that of previously studied coals (Progress Reports nos. 1--4). The BZ(ND) lignite was subjected to a previously developed stepwise depolymerization-liquefaction procedure [for details and recent applications see J. Shabtai and T. Skulthai, Proc. 1987 Internat. Confer. Coal Science, Elsevier, Amsterdam (J.A. Moulijn, K.A. Nater, and H.A.G. Chermin, Eds.), 1987, pp. 761764; and J. Shabtai, T. Skulthai, and I. Saito, Am. Chem. Soc. Div. Fuel Chem. Prepr., 31 (4), 15--23 (1986)]. The procedure, as summarized in Figure 1, consists essentially of the following sequential steps: (1) intercalation of the coal sample with catalytic amounts (5--20 %) of FeCl[sub 3] followed by mild hydrotreatment (HT) of the coal-FeCl[sub 3] intercalate; (2) base-catalyzed depolymerization (BCD) of the product from step 1, under super-critical conditions; and (3) hydroprocessing (HPR) of the depolymerized product from the two preceding steps, using a sulfided 6Co8Mo catalyst. The results obtained in processing the BZ(ND) lignite according to the above procedure are described
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Sequential low-temperature depolymerization and liquefaction of US coals
Suitable conditions for high-yield conversion of a Pittsburgh [number sign]8 (Pennsylvania) coal sample, supplied by the Argonne program and designated below as PB(PA) coal, were previously developed (see Progress Report no. 4, pp. 3--15; and Progress Report no. 6, pp- 3--4). In some recent experiments, the yield of low-boiling hydrocarbon fuel fractions (gasoline, kerosene and gas oil; b.p. up to 325[degrees]C) from this coal was further increased to a level of 70--72 wt % (MAF basis). The main emphasis of the research work during the reporting period was on the structural analysis of the depolymerized PB(PA) coal, with the uftimate objective of developing an average molecular structure for the predominant (71.5 -- 76.0 wt %) oil fraction (fr. no. 6, Figure 1) as well as for the small asphattene and asphaftol fractions (fr. no. 7 and 8, Figure 1) of this depolymerized product. The oil and asphaftene fractions of the depolymerized PB(PA) coal (Figure 1, fractions [number sign]6 and 7, respectively) were analyzed by gas chromatography/mass spectrometry (GC/MS). Figure 2 shows the reconstructed ion chromatogram for the oil fraction of the depolymerized PB(PA) coal. As seen, the bulk of the compounds present in this fraction elute in the 125--225[degrees]C range as an incompletely resolved hump. It is indicated that the oil contains a wide range of compound types
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Statin Inhibition of Fc Receptor–Mediated Phagocytosis by Macrophages Is Modulated by Cell Activation and Cholesterol
Objectives— An inflammatory response to altered lipoproteins that accumulate in the arterial wall is a major component of the pathogenesis of atherosclerosis. Statins reduce plasma levels of low-density lipoprotein (LDL) and are effective treatments for atherosclerosis. It is hypothesized that they also modulate inflammation. The aim of this study was to examine whether lovastatin inhibits macrophage inflammatory processes and clarify its mechanism of action.
Methods and Results— We examined the effects of statins on phagocytosis of antibody-coated red blood cells by cultured human monocytes and mouse peritoneal macrophages. Lovastatin, simvastatin, and zaragozic acid, a squalene synthase inhibitor, blocked Fc receptor–mediated phagocytosis by cultured human monocytes and mouse peritoneal macrophages. The inhibitory effect of lovastatin on Fc receptor–mediated phagocytosis was prevented completely by addition of mevalonate, farnesyl pyrophosphate, LDL, or cholesterol to the culture medium. The inhibitory effect of zaragozic acid was reversed by addition of LDL, but not by the addition of geranylgeranyl pyrophosphate, to the medium. In addition, the effect of lovastatin on phagocytosis is a function of cell activation because treatment of cells with tumor necrosis factor-α or lipopolysaccharide prevented inhibition of phagocytosis by lovastatin.
Conclusions— The inhibition of Fc receptor–mediated phagocytosis of lovastatin is related to its effect on cholesterol biosynthesis rather than its effect on the formation of isoprenoids
Multi-Year Application of Dairy Slurry on Grassland: Effects on Crop, Soil Biota, Soil Nutrients, and N\u3csub\u3e2\u3c/sub\u3eO Emission
The long-term effects of using manure as the principal nutrient source in intensive crop production systems are not well known. This paper reports on the effects of multi-year application of fertilizer or dairy slurry on a tall fescue (Festuca arundinacea Schreb.) sward. Slurry sustained greater grass yield than chemical fertilizer. Unlike fertilizer, slurry supplied 70 to 120 kg N/ha one year after application but little after one year; 4-years of manure applications built up the stable organic matter pool in the soil. Manure-N was less prone to leaching but more prone to N2O emissions than fertilizer-N. Manured soils had considerably more biological activity than fertilized soils. High rates of manure application increased soil P
Addition of Red Clover or Birdsfoot Trefoil in Alfalfa-based Mixtures to Improve the Forage Energy to Protein Balance
The low ratio of sugars (S) to crude proteins (CP) in alfalfa (AL, Medicago sativa L.) leads to inefficient use of nitrogen by ruminants. The objective was to determine if adding red clover (RC, Trifolium pratense L.) or birdsfoot trefoil (BT, Lotus corniculatus L.) with or without a grass species to AL improved the forage S/CP ratio. Treatments were 100% AL (control) or AL-based mixtures with RC or BT in three proportions (75, 50, or 25% of seeded legumes) with either no grass or with timothy (Phleum pratense L.) or tall fescue (Schedonorus arundinaceus Schreb. Dumort.), resulting in 21 treatments assigned to a randomized complete block design with four replications at three sites in Canada (Agassiz, BC; St-Anne-de-Bellevue, QC; StAugustin-de-Desmaures, QC). Species contribution and nutritive attributes measured at each harvest were weighted for yield as a proportion of the seasonal yield and expressed yearly for the first two post-seeding years. Regression analyses showed that forage S concentration increased, CP concentration tended to decrease, and the S/CP ratio increased from 0.3 to 0.5 (y = 0.002 x + 0.3; P = 0.003, R2 = 0.53) with the addition of up to 92% RC or up to 66% BT to AL-based mixtures. The addition of up to 61% TI or 55% TF did not impact the S/CP ratio of AL-based mixtures. Further studies are needed to determine if the improved forage S/CP ratio following the addition of RC or BT to AL-based mixtures leads to an improved N-use efficiency in ruminants
MOCDroid: multi-objective evolutionary classifier for Android malware detection
Malware threats are growing, while at the same time, concealment strategies are being used to make them undetectable for current commercial Anti-Virus. Android is one of the target architectures where these problems are specially alarming, due to the wide extension of the platform in different everyday devices.The detection is specially relevant for Android markets in order to ensure that all the software they offer is clean, however, obfuscation has proven to be effective at evading the detection process. In this paper we leverage third-party calls to bypass the effects of these concealment strategies, since they cannot be obfuscated. We combine clustering and multi-objective optimisation to generate a classifier based on specific behaviours defined by 3rd party calls groups. The optimiser ensures that these groups are related to malicious or benign behaviours cleaning any non-discriminative pattern. This tool, named MOCDroid, achieves an ac-curacy of 94.6% in test with 2.12% of false positives with real apps extracted from the wild, overcoming all commercial Anti-Virus engines from VirusTotal
Intelligent OS X malware threat detection with code inspection
With the increasing market share of Mac OS X operating system, there is a corresponding increase in the number of malicious programs (malware) designed to exploit vulnerabilities on Mac OS X platforms. However, existing manual and heuristic OS X malware detection techniques are not capable of coping with such a high rate of malware. While machine learning techniques offer promising results in automated detection of Windows and Android malware, there have been limited efforts in extending them to OS X malware detection. In this paper, we propose a supervised machine learning model. The model applies kernel base Support Vector Machine (SVM) and a novel weighting measure based on application library calls to detect OS X malware. For training and evaluating the model, a dataset with a combination of 152 malware and 450 benign were is created. Using common supervised Machine Learning algorithm on the dataset, we obtain over 91% detection accuracy with 3.9% false alarm rate. We also utilize Synthetic Minority Over-sampling Technique (SMOTE) to create three synthetic datasets with different distributions based on the refined version of collected dataset to investigate impact of different sample sizes on accuracy of malware detection. Using SMOTE datasets we could achieve over 96% detection accuracy and false alarm of less than 4%. All malware classification experiments are tested using cross validation technique. Our results reflect that increasing sample size in synthetic datasets has direct positive effect on detection accuracy while increases false alarm rate in compare to the original dataset
Primary Hyperparathyroidism Patients with Positive Preoperative Sestamibi Scan and Negative Ultrasound Are More Likely to Have Posteriorly Located Upper Gland Adenomas (PLUGs)
BackgroundStandard preoperative imaging for primary hyperparathyroidism usually includes sestamibi scanning (MIBI) and ultrasound (US). In a subset of patients with a positive MIBI and a negative US, we hypothesize that the parathyroid adenomas are more likely to be located posteriorly in the neck, where anatomically they are more difficult to detect by US.MethodsWe retrospectively reviewed the records of 661 patients treated for primary hyperparathyroidism between 2004 and 2009 at a tertiary referral center. We included patients who for their first operation had a MIBI that localized a single lesion in the neck and an US that found no parathyroid adenoma. We excluded patients with persistent or recurrent hyperparathyroidism, and patients with MIBIs that were negative, that had more than one positive focus, or that had foci outside of the neck. Sixty-six cases were included in the final analysis.ResultsA total of 54 patients (83%) had a single adenoma, 4 (6%) had double adenomas, and 7 (11%) had hyperplasia. Thirty-three patients (51%) had a single upper gland adenoma; 19 of these (58%) were posteriorly located upper gland adenomas (PLUGs). PLUGs occurred more often on the right side than on the left (P = 0.048, Fisher's test). PLUGs were also larger than other single adenomas (mean 1.85 vs. 1.48 cm, P = 0.021, t-test). Seventy-six percent of patients successfully underwent a unilateral or focused exploration. Six patients (9%) had persistent disease, which is double our group's overall average (4-5%).ConclusionsPrimary hyperparathyroid patients with preoperative positive MIBI and negative US are more likely to have PLUGs
The ALFAM2 database on ammonia emission from field-applied manure: Description and illustrative analysis
peer-reviewedAmmonia (NH3) emission from animal manure contributes to air pollution and ecosystem degradation, and the loss of reactive nitrogen (N) from agricultural systems. Estimates of NH3 emission are necessary for national inventories and nutrient management, and NH3 emission from field-applied manure has been measured in many studies over the past few decades. In this work, we facilitate the use of these data by collecting and organizing them in the ALFAM2 database. In this paper we describe the development of the database and summarise its contents, quantify effects of application methods and other variables on emission using a data subset, and discuss challenges for data analysis and model development. The database contains measurements of emission, manure and soil properties, weather, application technique, and other variables for 1895 plots from 22 research institutes in 12 countries. Data on five manure types (cattle, pig, mink, poultry, mixed, as well as sludge and “other”) applied to three types of crops (grass, small grains, maize, as well as stubble and bare soil) are included. Application methods represented in the database include broadcast, trailing hose, trailing shoe (narrow band application), and open slot injection. Cattle manure application to grassland was the most common combination, and analysis of this subset (with dry matter (DM) limited to <15%) was carried out using mixed- and fixed-effects models in order to quantify effects of management and environment on ammonia emission, and to highlight challenges for use of the database. Measured emission in this subset ranged from <1% to 130% of applied ammonia after 48 h. Results showed clear, albeit variable, reductions in NH3 emission due to trailing hose, trailing shoe, and open slot injection of slurry compared to broadcast application. There was evidence of positive effects of air temperature and wind speed on NH3 emission, and limited evidence of effects of slurry DM. However, random-effects coefficients for differences among research institutes were among the largest model coefficients, and showed a deviation from the mean response by more than 100% in some cases. The source of these institute differences could not be determined with certainty, but there is some evidence that they are related to differences in soils, or differences in application or measurement methods. The ALFAM2 database should be useful for development and evaluation of both emission factors and emission models, but users need to recognize the limitations caused by confounding variables, imbalance in the dataset, and dependence among observations from the same institute. Variation among measurements and in reported variables highlights the importance of international agreement on how NH3 emission should be measured, along with necessary types of supporting data and standard protocols for their measurement. Both are needed in order to produce more accurate and useful ammonia emission measurements. Expansion of the ALFAM2 database will continue, and readers are invited to contact the corresponding author for information on data submission. The latest version of the database is available at http://www.alfam.dk
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