Synthetic Hydrotalcites as suitable Co-based catalysts for Fischer-Tropsch Process

Nowadays it is imperative to develop economical and energy-efficient processes for the sustainable production of alternative fuels and chemicals. Fischer Tropsch synthesis (FT) is a well-established industrial process whereby these objectives can be achieved using syngas (mixture of H2, CO, CO2) as raw material. Syngas can be manufactured from CH4, coal or, as a new tendency, frombiomass. FT synthesis usually requires catalysts based on cobalt or iron. The typical products range is from methane to long chain hydrocarbons (waxes) [1]. Cobalt-based catalysts have been used for FT for long time due to their long life-times, high CO conversion and high selectivity to heavy hydrocarbons; they are moreover characterized by low activity towards the water-gas shift, so avoiding the CO2 formation. In this work, layered double or triple hydroxides, also known as synthetic hydrotalcites, are proposed and studied as FT catalysts. The choice of these materials allows to easily prepare solid phases, essentially based on mixed metal oxides, where specific metal atoms are homogeneously dispersed at an atomic level. Hydrotalcites are represented by the empirical formula [M(II)1-xM(III)x(OH)2]x+[An-x/n]x-mH2O where M(II) is a divalent cation such as Co, Mg, Zn, Ni, or Cu, M(III) is a trivalent cation such as Al, Cr, Fe or Ga; An- is an anion of charge n and m the molar amounts of co-intercalated water [2]. When calcined at proper temperatures, the random distribution of cations, characteristic of the hydroxide phase, is maintained in the resulting mixed oxide. Hydrotalcite based materials have been recently reported as good catalysts for several processes in the energy field, such as hydrogen production by steam reforming of methanol and ethanol, photocatalytic water splitting and so on [3-5]. A series a Co-Zn-Al hydrotalcites, with increasing Co contents was synthesized and characterized. Preliminary tests on their catalytic activity in the FT process resulted in a satisfactory outcome

Enhanced recovery in colorectal surgery: a multicentre study

<p>Abstract</p> <p>Background</p> <p>Major colorectal surgery usually requires a hospital stay of more than 12 days. Inadequate pain management, intestinal dysfunction and immobilisation are the main factors associated with delay in recovery. The present work assesses the short and medium term results achieved by an enhanced recovery program based on previously published protocols.</p> <p>Methods</p> <p>This prospective study, performed at 12 Spanish hospitals in 2008 and 2009, involved 300 patients. All patients underwent elective colorectal resection for cancer following an enhanced recovery program. The main elements of this program were: preoperative advice, no colon preparation, provision of carbohydrate-rich drinks one day prior and on the morning of surgery, goal directed fluid administration, body temperature control during surgery, avoiding drainages and nasogastric tubes, early mobilisation, and the taking of oral fluids in the early postoperative period. Perioperative morbidity and mortality data were collected and the length of hospital stay and protocol compliance recorded.</p> <p>Results</p> <p>The median age of the patients was 68 years. Fifty-two % of the patients were women. The distribution of patients by ASA class was: I 10%, II 50% and III 40%. Sixty-four % of interventions were laparoscopic; 15% required conversion to laparotomy. The majority of patients underwent sigmoidectomy or right hemicolectomy. The overall compliance to protocol was approximately 65%, but varied widely in its different components. The median length of postoperative hospital stay was 6 days. Some 3% of patients were readmitted to hospital after discharge; some 7% required repeat surgery during their initial hospitalisation or after readmission. The most common complications were surgical (24%), followed by septic (11%) or other medical complications (10%). Three patients (1%) died during follow-up. Some 31% of patients suffered symptoms that delayed their discharge, the most common being vomiting or nausea (12%), dyspnoea (7%) and fever (5%).</p> <p>Conclusion</p> <p>The following of this enhanced recovery program posed no risk to patients in terms of morbidity, mortality and shortened the length of their hospital stay. Overall compliance to protocol was 65%. The following of this program was of benefit to patients and reduces costs by shortening the length of hospital stay. The implantation of such programmes is therefore highly recommended.</p

Topiramate-Induced Modulation of Hepatic Molecular Mechanisms: An Aspect for Its Anti-Insulin Resistant Effect

Topiramate is an antiepileptic drug known to ameliorate insulin resistance besides reducing body weight. Albeit liver plays a fundamental role in regulation of overall insulin resistance, yet the effect of topiramate on this organ is controversial and is not fully investigated. The current work aimed to study the potential hepatic molecular mechanistic cassette of the anti-insulin resistance effect of topiramate. To this end, male Wistar rats were fed high fat/high fructose diet (HFFD) for 10 weeks to induce obese, insulin resistant, hyperglycemic animals, but with no overt diabetes. Two HFFD-groups received oral topiramate, 40 or 100 mg/kg, for two weeks. Topiramate, on the hepatic molecular level, has opposed the high fat/high fructose diet effect, where it significantly increased adiponectin receptors, GLUT2, and tyrosine kinase activity, while decreased insulin receptor isoforms. Besides, it improved the altered glucose homeostasis and lipid profile, lowered the ALT level, caused subtle, yet significant decrease in TNF-α, and boosted adiponectin in a dose dependent manner. Moreover, topiramate decreased liver weight/, visceral fat weight/, and epididymal fat weight/body weight ratios. The study proved that insulin-resistance has an effect on hepatic molecular level and that the topiramate-mediated insulin sensitivity is ensued partly by modulation of hepatic insulin receptor isoforms, activation of tyrosine kinase, induction of GLUT2 and elevation of adiponectin receptors, as well as their ligand, adiponectin, besides its known improving effect on glucose tolerance and lipid homeostasis

Point absorbers in Advanced LIGO

Small, highly absorbing points are randomly present on the surfaces of the main interferometer optics in Advanced LIGO. The resulting nanometer scale thermo-elastic deformations and substrate lenses from these micron-scale absorbers significantly reduce the sensitivity of the interferometer directly though a reduction in the power-recycling gain and indirect interactions with the feedback control system. We review the expected surface deformation from point absorbers and provide a pedagogical description of the impact on power buildup in second generation gravitational wave detectors (dual-recycled Fabry–Perot Michelson interferometers). This analysis predicts that the power-dependent reduction in interferometer performance will significantly degrade maximum stored power by up to 50% and, hence, limit GW sensitivity, but it suggests system wide corrections that can be implemented in current and future GW detectors. This is particularly pressing given that future GW detectors call for an order of magnitude more stored power than currently used in Advanced LIGO in Observing Run 3. We briefly review strategies to mitigate the effects of point absorbers in current and future GW wave detectors to maximize the success of these enterprises