Surgical portosystemic shunts versus devascularisation procedures for prevention of variceal rebleeding in people with hepatosplenic schistosomiasis

BACKGROUND: Hepatosplenic schistosomiasis is an important cause of variceal bleeding in low-income countries. Randomised clinical trials have evaluated the outcomes of two categories of surgical interventions, shunts and devascularisation procedures, for the prevention of variceal rebleeding in people with hepatosplenic schistosomiasis. The comparative overall benefits and harms of these two interventions are unclear. OBJECTIVES: To assess the benefits and harms of surgical portosystemic shunts versus oesophagogastric devascularisation procedures for the prevention of variceal rebleeding in people with hepatosplenic schistosomiasis. SEARCH METHODS: We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, CENTRAL, MEDLINE, Embase, Science Citation Index Expanded, LILACS, reference lists of articles, and proceedings of relevant associations for trials that met the inclusion criteria (date of search 11 January 2018). SELECTION CRITERIA: Randomised clinical trials comparing surgical portosystemic shunts versus oesophagogastric devascularisation procedures for the prevention of variceal rebleeding in people with hepatosplenic schistosomiasis. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the trials and extracted data using methodological standards expected by Cochrane. We assessed risk of bias according to domains and risk of random errors with GRADE and Trial Sequential Analysis. We assessed the certainty of evidence using the GRADE approach. MAIN RESULTS: We found two randomised clinical trials including 154 adult participants, aged between 18 years and 65 years, diagnosed with hepatosplenic schistosomiasis. One of the trials randomised participants to proximal splenorenal shunt versus distal splenorenal shunt versus oesophagogastric devascularisation with splenectomy, and the other randomised participants to distal splenorenal shunt versus oesophagogastric devascularisation with splenectomy. In both trials the diagnosis of hepatosplenic schistosomiasis was made based on clinical and biochemical assessments. The trials were conducted in Brazil and Egypt. Both trials were at high risk of bias.We are uncertain as to whether surgical portosystemic shunts improved all-cause mortality compared with oesophagogastric devascularisation with splenectomy due to imprecision in the trials (risk ratio (RR) 2.35, 95% confidence interval (CI) 0.55 to 9.92; participants = 154; studies = 2). We are uncertain whether serious adverse events differed between surgical portosystemic shunts and oesophagogastric devascularisation with splenectomy (RR 2.26, 95% CI 0.44 to 11.70; participants = 154; studies = 2). None of the trials reported on health-related quality of life. We are uncertain whether variceal rebleeding differed between surgical portosystemic shunts and oesophagogastric devascularisation with splenectomy (RR 0.39, 95% CI 0.13 to 1.23; participants = 154; studies = 2). We found evidence suggesting an increase in encephalopathy in the shunts group versus the devascularisation with splenectomy group (RR 7.51, 95% CI 1.45 to 38.89; participants = 154; studies = 2). We are uncertain whether ascites and re-interventions differed between surgical portosystemic shunts and oesophagogastric devascularisation with splenectomy. We computed Trial Sequential Analysis for all outcomes, but the trial sequential monitoring boundaries could not be drawn because of insufficient sample size and events. We downgraded the overall certainty of the body of evidence for all outcomes to very low due to risk of bias and imprecision. AUTHORS' CONCLUSIONS: Given the very low certainty of the available body of evidence and the low number of clinical trials, we could not determine an overall benefit or harm of surgical portosystemic shunts compared with oesophagogastric devascularisation with splenectomy. Future randomised clinical trials should be designed with sufficient statistical power to assess the benefits and harms of surgical portosystemic shunts versus oesophagogastric devascularisations with or without splenectomy and with or without oesophageal transection.http://www.cochranelibrary.comSurger

A Comparative Study of Outranking Methods for Multi-Criteria Optimization of Electromechanical Modules

The paper presents a comparative assessment of the procedures for applying two outranking methods in solving multi-criteria optimization tasks. The conducted study compares the fundamental PROMETHEE (Preference Ranking Organization METHod for Enrichment Evaluations) method, which is widely proposed to support selection of the best compromise alternative in multi-criteria tasks, with the newly developed RAZOR (Ranking of Alternatives by Z-score Operation Ratings) method. The paper describes the ranking methods and provides demonstrative numerical examples for existing electromechanical modules. The results of the numerical examples from the conducted multi-criteria optimization on a number of given criteria are presented. The study demonstrated that the calculation procedure in PROMETHEE method demands certain level of preliminary knowledge, but provides fine setting of preferences by the decision-maker. The RAZOR method, on the other hand, demands no preliminary knowledge and it is easier to visualize graphically

Synthesis and characterization of mixed oxides derivate from Li modified Mg-Al hydrotalcites

Lithium modified Mg/Al hydrotalcite-like samples with different Li content were synthesized using co-precipitation followed by calcination at 500 °C. The samples were characterized by means of XRD, DRIFTS, SEM-EDS, LDPSA and MIP. Results from this study indicated that the addition of Li modifier influences the change in structural, textural and morphological characteristics, more pronounced in samples with higher lithium content

Effects of preparation conditions on the catalytic activity of chicken eggshell catalysts for the transesterification of oils to biodiesel

Eggshell based catalysts were synthesized by calcination (600 and 900 ºC, 4 h) of raw and rehydration (RH) modified (RH-temperature of 80 ºC, S/L ratio of 1/5, and RH-time of 6 h) eggshell. After RH-treatment, the sample underwent calcination at 600 ºC, 4 h. Obtained catalysts were characterized by XRD, SEM, N2-physisorption, and Hg-porosimetry, whereas the catalytic activity was analyzed in a batch reactor (reaction temperature of 60 ºC, sunflower oil/methanol molar ratio of 1/12, and catalyst concentration of 4 wt.%). The concentration of fatty acid methyl esters (FAMEs) was determined by HPLC. The reaction has reached equilibrium (FAME > 97%) with rehydrated catalyst for 1.5 h, whereas with catalyst calcined at 900 ºC for 4 h

Supported Nickel-Based Catalysts for Partial Hydrogenation of Edible Oils

Nickel-based catalysts, supported on diatomite, silica gel and perlite, with high nickel loadings, have been prepared by precipitation-deposition method. Various nickel precursor salts were used for the preparation of catalyst precursors. In the precursor state, the catalysts were characterized using nitrogen physisorption, mercury porosimetry, infrared, and X-ray diffraction spectroscopy. The reducibility of catalyst precursors was evaluated using hydrogen temperature programmed reduction. Hydrogen chemisorption and X-ray photoelectron spectroscopy measurements were performed with the aim of characterizing the chemical state of the catalyst precursors. This research was focused on the study of some major factors on the state, dispersion and reducibility of a deposited Ni2+ phase by the combined use of mentioned experimental techniques. We have examined the influence of the nature of support and the use of modifiers on activity of nickel-based catalysts in the partial hydrogenation of sunflower and soybean oils. Nitrogen physisorption and mercury porosimetry data showed that synthesis operating conditions and pore structure of supports have a profound effect on the textural properties of catalyst precursors. The analysis of infrared and X-ray diffraction spectra showed the existence of chemical species and phases which indicate the different extent of interaction between the support and the active metal. Temperature programmed reduction study revealed that the reduction features depend on the identity of the nickel precursor salt and its interaction with the support. A stronger interaction of the supported Ni2+ phase with support hinders the reduction of catalyst precursors. Hydrogen chemisorption results showed the presence of nickel crystallites varying from 5 to 47 nm in size. The X-ray photoelectron spectroscopy data confirmed the formation surface species with different strength of interaction and different nickel crystallite sizes. The hydrogenation results showed significant differences, depending on the support and the modifier, as well as structural characteristics of reduced catalyst precursors. The results show the importance of modifiers in the control of the activity and selectivity of the partial hydrogenation process. The developed kinetic models of the hydrogenation of soybean and sunflower oils over studied catalytic systems were found useful in the prediction of the rate of reactions, product selectivity and catalytic activity

Solid Green Biodiesel Catalysts Derived from Coal Fly Ash

Coal fly ash (CFA) is generated during the combustion of coal for energy production. Many studies are based on its utilization as the most abundant, cheap aluminosilicate industrial residue, which is recognized as a risk for the environment and human health. The present review is focused on CFA origin, chemical properties, and its catalytic application for biodiesel production. The aluminosilicate nature and the presence of rare earth elements make CFA suitable for different adsorption, catalytic, and extraction processes for obtaining valuable products including alternative fuels and pure elements. However, the presence of toxic elements is a potential environmental problem, which should be solved in order to avoid soil, water, and air pollution. The most used modification methods are alkali activation, hydrothermal, and thermal treatment that improve the structural, morphological, and textural properties. The active catalytic form could be obtained by impregnation or ion exchange method. It was found that such synthesized materials have significant catalytic potential in the biofuel chemistry. In the case of biodiesel production, the high values of conversion or yield can be achieved under mild low-energy reaction conditions in the presence of low-cost waste-based catalysts

Synthesis and characterization of mixed oxides derivate from Li modified Mg-Al hydrotalcites

Lithium modified Mg/Al hydrotalcite-like samples with different Li content were synthesized using co-precipitation followed by calcination at 500 °C. The samples were characterized by means of XRD, DRIFTS, SEM-EDS, LDPSA and MIP. Results from this study indicated that the addition of Li modifier influences the change in structural, textural and morphological characteristics, more pronounced in samples with higher lithium content

XPS study of the nickel oxidation state in the reduced (Ag)NiMg/SiO2 vegetable oil hydrogenation catalysts

Two series of (Ag)NiMg/SiO2 catalysts are synthesized on SiO2 support derived from two silica sources: diatomite activated at 800oC (Series a; Mg/Ni=0.1 and SiO2/Ni=1.07) and synthetic water glass (Series b; Mg/Ni=0.1 and SiO2/Ni=1.15). The modification with silver is made at three molar Ag/Ni ratios, namely 0.0025, 0.025 and 0.1. The effect of the source of SiO2 support as well as of the Ag presence and content on the nickel oxidation state in the co-precipitated (Ag)NiMg/SiO2 catalysts after reduction-passivation procedure are studied by XPS. The peak-fitting of the composite Ni2p level confirms that nickel on the surface is presented in Ni0 and Ni2+ oxidation states. The higher content of Ni0 on the surface of the diatomite supported catalysts shows that the metallic nickel is more stable to oxidation in comparison of the water glass supported ones

Effect of Nickel Salts on the Dispersion of Nickel and Reducibility of Supported Ni-Mg Catalyst Precursors Prepared by Precipitation-Deposition

Diatomite supported Ni-Mg catalyst precursors (Ni-Mg/D) with a constant Ni/Mg ratio, prepared by the precipitation-deposition method using different nickel salts, sulfamate, nitrate, chloride, acetate or formate, were studied by hydrogen chemisorptions and temperature programmed reduction (H2- TPR).The results showed that the dispersion of nickel and the reducibility of the prepared catalyst precursors were different depending upon the counter ion of the nickel salt. Among the studied nickel salts, the best results for the dispersion of metallic Ni and reducibility of Ni-Mg/D catalyst precursors were achieved using nickel sulfamate salt

Structure and morphology of calcined lanthanum doped hydrotalcite

Mg-Al hydrotalcites (Mg/Al molar ratio 3/1) doped with varying amounts of lanthanum were prepared using co-precipitation followed by calcination in order to study the effect of lanthanum on their structure and morphology. Samples were characterized by several methods: XRD, FT-IR, SEM-EDS, LDPSA and MIP. It was found that the addition of lanthanum affects the structure and morphology of the obtained metal oxides derived from Ladoped Mg-Al hydrotalcites, making it effective dopant for (Mg/Al/La)Otype materials, being very promising for various catalytic reactions