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Noninvasive Fibrosis Scores as Prognostic Markers for Varices Needing Treatment in Advanced compensated Liver cirrhosis

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Open Journal of Gastroenterology 2017年第8期7卷 230-242页

作者： Elham Ahmed Hassan Abeer Sharaf El-Din Abd El-Rehim Zain El-Abdeen Ahmed Sayed Ahmed Mohmmed Ashmawy Emad Farah Mohamed Kholef Abeer Sabry Wael Abd-Elgwad Elsewify Department of Tropical Medicine and Gastroenterology Faculty of Medicine Assiut University Assiut Egypt Department of Internal Medicine Faculty of Medicine Assiut University Assiut Egypt Department of Clinical pathology Faculty of Medicine Aswan University Aswan Egypt Department of Internal Medicine Faculty of Medicine Helwan University Cairo Egypt Department of Internal Medicine Faculty of Medicine Aswan University Aswan Egypt

Background/purpose: Noninvasive assessment of esophageal varices (EVs), their size and bleeding stigmata may reduce endoscopic burden, cost and drawbacks. We aimed to evaluate the diagnostic performance of noninvasive fibrosis scores (AAR, APRI, FIB-4, King and VITRO scores) in predicting the presence of EVs and high risk varices needing treatment (VNT) in HcV-related cirrhosis of Egyptian patients. Methods: This prospective study included 154 HcV-related advanced compensated cirrhotic patients with no history of bleeding who underwent screening endoscopy for EVs. AAR, APRI, FIB-4, King and VITRO scores were assessed. Results: Esophageal varices were found in 120 patients (77.9%) and VNT in 92 patients (59.7%). Apart from AAR, all scores demonstrated statistically significant correlations with the presence and the size of EVs. Using area under receiver operating characteristic curve (AUc), these scores were good predictors for the presence of EVs and VNT, where VITRO score had the highest AUc (0.920 and 0.900) and accuracy (97.1% and 87%), sensitivity (75, 82.6%), specificity (100, 93.5%), PPV (100, 95%) and NPV (53.2, 78.4%) with cutoffs >1.3 and >1.8 respectively. conclusion: Noninvasive fibrosis scores can predict the presence of EVs and VNT. VITRO score was the best predictor with higher accuracy for clinical applicability than studied scores.

关键词： Esophageal Varices Hepatitis c Liver cirrhosis VITRO Score

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Effect of Pyrolysis Temperature and Feedstock Type on Agricultural Properties and Stability of Biochars

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Agricultural Sciences 2017年第9期8卷 914-933页

作者： Rafaela Feola conz Thalita F. Abbruzzini cristiano A. de Andrade Debora M. B. P. Milori carlos E. P. cerri Department of Soil Sciences University of Sao Paulo Piracicaba Brazil Department of Environmental Systems Sciences Institute of Agricultural Sciences Swiss Federal Institute of Technology Zurich Switzerland Brazilian Agricultural Research Corporation Jaguariuna Brazil Brazilian Agricultural Research Corporation Sao Carlos Brazil

Pyrolysis temperature and feedstock type used to produce biochar influence the physicochemical properties of the obtained product, which in turn display a range of results when used as soil amendment. From soil carbon (c) sequestration strategy to nutrient source, biochar is used to enhance soil properties and to improve agricultural production. However, contrasting effects are observed from biochar application to soil results from a wide range of biochar’s properties in combination with specific environmental conditions. Therefore, elucidation on the effect of pyrolysis conditions and feedstock type on biochar properties may provide basic information to the understanding of soil and biochar interactions. In this study, biochar was produced from four different agricultural organic residues: Poultry litter, sugarcane straw, rice hull and sawdust pyrolysed at final temperatures of 350°c, 450°c, 550°c and 650°c. The effect of temperature and feedstock type on the variability of physicochemical properties of biochars was evaluated through measurements of pH, electrical conductivity, cation exchange capacity, macronutrient content, proximate and elemental analyses, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analyses. Additionally, an incubation trial was carried under controlled conditions to determine the effect of biochar stability on cO2-eq emissions. Results showed that increasing pyrolysis temperature supported biochar stability regardless of feedstock, however, agricultural properties varied widely both as an effect of temperature and feedstock. Animal manure biochar showed higher potential as nutrient source rather than a c sequestration strategy. Improving the knowledge on the influence of pyrolysis temperature and feedstock type on the final properties of biochar will enable the use of better tailored materials that correspond to the expected results while considering its interactions with environmental conditions.

关键词： characterization GHG c Sequestration char Organic c

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SELEcTIVE HYDROGENATION OF 3,4-DIMETHOXYBENZOPHENONE IN LIQUID PHASE OVER PD/c cATALYST IN A SLURRY REAcTOR

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cANADIAN JOURNAL OF cHEMIcAL ENGINEERING 2014年第12期92卷 2157-2165页

作者： Tiwari, Manishkumar S. Yadav, Ganapati D. Ng, Flora T. T. Inst Chem Technol Dept Chem Engn Mumbai 400019 Maharashtra India Univ Waterloo Dept Chem Engn Waterloo ON N2L 3G1 Canada

Selective hydrogenation of benzophenone to benzhydrol is industrially relevant. In the current work, selective hydrogenation of 3,4-dimethoxybenzophenone (3,4-DMBP) to 3,4-dimethoxybenzhydrol (3,4-DMBH) was investigated over 5% w/w Pd/c and 5% w/w Pt/c as catalysts in a slurry reactor. The effects of hydrogen partial pressure (0.2-1MPa), catalyst loading (2.0x10(-4) to 8.0x10(-4)g/cm(3)), initial concentration of 3,4-dimethoxybenzophenone (5.0x10(-6) to 1.5x10(-4)mol/cm(3)) and temperature (40-70 degrees c) on rate of reaction and selectivity were studied. Effect of solvent such as methanol, ethanol, 2-propanol and tetrahydrofuran (THF) was also investigated. 5% w/w Pd/c was the better catalyst with THF as the best solvent, which gave 100 % conversion and 80 % selectivity in 1h for 0.5MPa hydrogen pressure at 60 degrees c. The Langmuir-Hinshelwood-Hougen-Watson model was fitted. The intrinsic kinetics and mechanism of hydrogenation were established.

关键词： catalytic hydrogenation 3 4-Dimethoxybenzopheone Pd c 3 4-Dimethoxybenzhydrol kinetics

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颗粒尺寸、挤压和时效时间对Sic颗粒增强Al-cu-Mg基复合材料微观结构及硬度的影响

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粉末冶金材料科学与工程 2017年第1期22卷 26-32页

作者：沈茹娟王德高郭柏松宋旼中南大学深圳研究院深圳518057 中南大学粉末冶金国家重点实验室长沙410083

研究Si c颗粒尺寸、挤压和时效时间对粉末冶金法制备的Si c颗粒增强Al-cu-Mg基复合材料微观结构及硬度的影响。研究表明,挤压对复合材料的微观结构和硬度有重要影响,能够极大促进增强体在Al基体中的均匀分布和复合材料的致密化。挤压后... 详细信息

研究Si c颗粒尺寸、挤压和时效时间对粉末冶金法制备的Si c颗粒增强Al-cu-Mg基复合材料微观结构及硬度的影响。研究表明,挤压对复合材料的微观结构和硬度有重要影响,能够极大促进增强体在Al基体中的均匀分布和复合材料的致密化。挤压后的复合材料残留微孔减少,密度和硬度均得到显著提高。时效时间和Si c尺寸对复合材料中析出相的数量及尺寸有显著影响。采用较小尺寸的Si c作为增强体时,随时效时间延长,析出相在基体中均匀析出,没有明显长大,在时效12 h内没有出现峰时效。然而,采用较大尺寸的Si c作为增强体时,随时效时间延长,基体中的析出相不是很均匀,并有部分发生明显粗化,在同样的时效时间范围内出现了峰时效。

关键词： Al基复合材料 Si c 颗粒尺寸颗粒分布时效时间硬度

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Synthesis and characterization of novel activated carbon from Medlar seed for chromium removal: Experimental analysis and modeling with artificial neural network and support vector regression

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Resource-Efficient Technologies 2017年第3期3卷 236-248页

作者： Mostafa Solgi Tahereh Najib Shahyar Ahmadnejad Bahram Nasernejad Chemical Engineering Department Babol Noshirvani University of Technology P.O. Box 484 *** Babol Iran Chemical Engineering Department Amirkabir University of Technology (Tehran Polytechnic) P.O. Box 15875-4413 Tehran Iran Electrical Engineering Department Babol Noshirvani University of Technology P.O. Box 15875-4413 Babol Iran

In this study, for the first time the activated carbon has been produced from medlar seed (Mespilus germanica) via chemical activation with KOH. The carbonization process was carried out at different temperatures of 450, 550, 650 and 750 °c. The Nitrogen adsorption-desorption, Fourier transform infrared spectroscopy (FTIR) and Field Emission Scanning Electron Microscope (FESEM) analyses were carried out on the adsorbents. The effect of operating parameters, such as pH, initial concentration of cr(VI), adsorbent dosage and contact time were investigated. The experimental data showed better agreement with the Langmuir model and the maximum adsorption capacity was evaluated to be 200 mg/g. Kinetic studies indicated that the adsorption process follows the pseudo second-order model and the chemical reaction is the rate-limiting step. Thermodynamic parameters showed that the adsorption process could be considered a spontaneous (ΔG < 0), endothermic (ΔH > 0) process which leads to an increase in entropy (ΔS > 0). The application of support vector machine combined with genetic algorithm (SVM-GA) and artificial neural network (ANN) was investigated to predict the percentage of chromium removal from aqueous solution using synthesized activated carbon. The comparison of correlation coefficient (R 2 ) related to ANN and the SVR-GA models with experimental data proved that both models were able to predict the percentage of chromium removal, by synthetic activated carbon while the SVR-GA model prediction was more accurate.

关键词： Activated carbon chromium removal Medlar seed Artificial neural network Support vector regression qe (mg/g) adsorption capacity at equilibrium time qe,cal (mg/g) theoretical equilibrium adsorption capacity k1 (1/min) pseudo-first order adsorption rate constant k2 (g/mg min) pseudo-second order adsorption rate constant kid (g/mg min) intra-particle diffusion rate constant c constant indicating thickness of the boundary lay qmax (mg/g) maximum adsorption capacity B (L/g) Langmuir isotherm constant n adsorption intensity KF (mg/g) Freundlich isotherm constant ΔS o (J/mol K) standard entropy change ΔGo (kJ/mol) Gibbs free energy change ΔHo (kJ/mol) standard enthalpy change R (j/mol K) universal gas constant T (K) temperature kd (ml/g) distribution coefficient Δq (%) normalized standard deviation

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Hardness of Pillared-Graphene Nanostructures via Indentation Simulation

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MRS ADVANcES 2017年第1期2卷 45-50页

作者： Sasaki, R. Shintani, K. Univ Electrocommun Dept Mech Engn & Intelligent Syst 1-5-1 Chofugaoka Chofu Tokyo 1828585 Japan

Pillared-graphene is one of nanocarbon hybrids. It consists of graphene sheets and carbon nanotubes (cNTs);the latter are bonded vertically to the former. In order to investigate the hardness of pillared-graphene, indentation simulations are performed using a molecular dynamics method. It is revealed that the hardness of pillared-graphene increases with increasing the diameter of the cNTs, whereas it decreases with increasing the distance between cNTs or temperature. Such tendencies can be understood by considering the deformations of graphene and cNTs individually.

关键词： c nano-indentation hardness

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Recent advances in guest effects on spin-crossover behavior in Hofmann-type metal-organic frameworks

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coordination chemistry Reviews 2017年 335卷 28-43页

作者： Zhao-Ping Ni Jun-Liang Liu Md. Najbul Hoque Wei Liu Jin-Yan Li Yan-cong chen Ming-Liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of Chemistry Sun Yat-Sen University Guangzhou 510275 PR China

The incorporation of spin-crossover (ScO) properties into metal-organic frameworks (MOFs) is an appealing subclass of multifunctional MOFs with potential applications in molecular sensing. This review focuses on the design of ScO Hofmann-type MOFs, with emphasis on the guest effect on their ScO properties. The influences of guest size, dielectric constant, π ⋯ π interaction, hydrogen bonding interactions, weak X⋯M′ covalent bonding, and chemical reaction on the ScO properties of Hofmann-type MOFs are systematically explored. Further enhancements of sensing properties are also illustrated.

关键词： azpy trans -4,4′-azopyridine pz pyrazine py pyridine 3-Fpy 3-fluoropyridine 3-NH 2 py 3-aninopyridine phpy 4-phenylpyridine bpac bis(4-pyridyl)acetylene bpeben 1,4-bis(4-pyridylethynyl)-benzene dpsme 4,4′-di(pyridylthio)methane bipytz 3,6-bis(4-pyridyl)-1,2,4,5-tetrazine bpmp 1,4-bis(pyridin-4-ylmethyl)piperazine bpp 2,5-bis(pyrid-4-yl)pyridine dpb 1,4-di(pyridin-4-yl)benzene bz benzene Ac acetone Acn acetonitrile IBz iodobenzene MeOH methanol EtOH ethanol Tol toluene fur furan pyr pyrrole thio thiophene Mal maleic anhydride HMal Maleic acid bpbd 2,3-bis(4′-pyridyl)-2,3-butanediol n -PrOH 1-propanol c 6 H 12 cyclohexane s -BuOH sec -butanol i -BuOH isobutanol i -PrOH isopropanol naph naphthalene anth anthracene TclBz 1,2,4-trichlorobenzene clBz chlorobenzene BrBz bromobenzene dpe 1,2-di(4-pyridyl)ethylene dpa 1,2-di(4-pyridyl)ethane bbz bibenzyl stb stilbene bpb bis(4-pyridyl)butadiyne bipydz 3,6-bis(4-pyridyl)-1,2-diazine c 7 H 8 2,5-norbornadiene Spin-crossover Host-guest interaction Hofmann-type Metal-organic frameworks

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Design and commissioning of a thermal stability test-rig for mixtures as working fluids for ORc applications

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Energy Procedia 2017年 129卷 176-183页

作者： L. Keulen c. Landolina A. Spinelli P. Iora c. Invernizzi L. Lietti A. Guardone Department of Aerospace Science & Technology Politecnico di Milano Via La Masa 35 20156 Milano Italy Department of Mechanical Engineering Politecnico di Milano Via La Masa 1 20156 Milano Italy Energy Department Politecnico di Milano Via Lambruschini 4 20156 Milano Italy Department of Mechanical and Industrial Engineering University of Brescia Via Branze 38 25121 Brescia Italy

A novel test-rig for studying the thermal stability of mixtures as working fluids for ORc applications was designed and commissioned at the Laboratory of compressible-fluid dynamics for Renewable Energy Applications (cREA) of Politecnico di Milano, in collaboration with the University of Brescia. The set-up is a standard one, in which a vessel containing the fluid under scrutiny is placed in a vertical oven for ~ 100 hours at a constant temperature T = T stress . During the test, the pressure P is monitored to detect thermal decomposition of the fluid. After the test, the vessel is placed in a controlled thermal bath, where the pressure is measured at different value of the temperature T , with T < T stress and T < T c ( T c critical temperature). The resulting isochoric pressure-temperature dependence is compared to that obtained before the fluid underwent thermal stress. If departure from the initial fluid behavior is observed, significant thermal decomposition occurred and a chemical analysis of the decomposition products is carried out using gas chromatography and mass spectroscopy. The novelty of the set-up is the possibility of taking samples of both liquid and vapor phases of the fluid, a capability that was introduced to study thermal decomposition of mixtures, whose composition depends on the pressure and temperature, as well as to capture the more volatile products of thermal decomposition of pure fluids and mixtures. Preliminary experimental results are reported for the pure siloxane fluid MDM (Octamethyltrisiloxane, c 8 H 24 O 2 Si 3 ).

关键词： Thermal stability Working fluids for ORc applications Binary mixtures of siloxane fluids MM (Hexamethyldisiloxane c 6 H 18 OSi 2 ) MDM (Octamethyltrisiloxane c 8 H 24 O 2 Si 3 ) ORc applications

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Influence of Pretreatment on Kinetics at carbon Electrodes and consequences for Flow Battery Performance

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MRS ADVANcES 2017年第21-22期2卷 1131-1142页

作者： Buckley, D. N. Bourke, A. Lynch, R. P. Quill, N. Miller, M. A. Wainright, J. S. Savinell, R. F. Univ Limerick Bernal Inst Dept Phys & Energy Limerick Ireland Case Western Reserve Univ Dept Chem Engn Cleveland OH 44106 USA Waterford Inst Technol Sch Engn Waterford Ireland

Using cyclic voltammetry (cV) and electrochemical impedance spectroscopy (EIS), it was shown for four different types of carbon that electrode treatments at negative potentials enhance the kinetics of V-IV-V-V and inhibit the kinetics of V-II-V-III while electrode treatments at positive potentials inhibit the kinetics of V-IV-V-V and enhance the kinetics of V-II-V-III. These observations may explain conflicting reports in the literature. The potentials required for activation and deactivation of electrodes were examined in detail. The results suggest that interchanging the positive and negative electrodes in a vanadium flow battery (VFB) would reduce the overpotential at the negative electrode and so improve the performance. This is supported by flow-cell experiments. Thus, periodic catholyte-anolyte interchange, or equivalent alternatives such as battery overdischarge, show promise of improving the voltage efficiency of VFBs.

关键词： kinetics c V

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Thermal Rectification characteristics of Graphene Nanoribbons of Asymmetric Geometries

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MRS ADVANcES 2017年第1期2卷 15-20页

作者： Iwata, T. Shintani, K. Univ Electrocommun Dept Mech Engn & Intelligent Syst 1-5-1 Chofugaoka Chofu Tokyo 1828585 Japan

The rectification of heat in graphene nanoribbons (GNRs) of asymmetric geometries is investigated by means of nonequilibrium molecular dynamics (NEMD). Two kinds of geometries of GNRs are addressed;a trapezoidal or T-shaped step is inserted halfway through a GNR in its longitudinal direction. The thermal conductivities (Tcs) of the GNRs in the two longitudinal directions, forward and backward, are calculated making their width and temperature change. It is revealed that the thermal rectification ratio (TRR) of T-shaped GNRs are larger than those of trapezoidal GNRs and that the characteristics of heat transport in such asymmetric GNRs can be understood by considering the local phonon density of states (DOSs).

关键词： c nanoscale thermal conductivity

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