High temperature dewatering of ethanol by vapour permeation and pervaporation with HybSi® membranes

Ethanol is one of the most important commodity chemicals used in a broad range of applications and can be produced by the hydrolysis of ethylene, though by far the largest fraction of ethanol is produced via fermentation mainly using 1st generation feedstock. Regardless of the source of the ethanol, from fermentation or from direct hydration of ethylene, the product is normally a dilute aqueous solution. The product is fed to a distillation system to concentrate ethanol. The separation of ethanol and water is complicated because ethanol and water form an azeotrope at 95.6 weight% ethanol. It is not possible to produce pure ethanol from an azeotropic mixture by normal distillation. Pervaporation is a method for dehydration of organics such as ethanol, which substantially avoids drawbacks of azeotropic distillation and adsorption. As the pervaporation process is not governed by thermodynamic equilibria and the selectivity is determined by the difference in permeation rates of components through the membrane, mixtures of components with close boiling points and azeotropic mixtures can be effectively separated. Pervaporation exhibits its highest efficiency in a concentration range of the ethanol-water mixture where distillation is least effective, namely, at high ethanol concentrations of 90-95 wt.%, especially in the vicinity of the azeotropic concentration. Previous studies have shown that hybrid distillation processes combined with either pervaporation or vapour permeation can be very attractive for the separation of liquid mixtures. Such a hybrid process leads to large energy savings when the membrane is used for breaking the azeotrope. At the preferred process conditions currently available commercial polymer and zeolite membranes cannot be used. In this study, the focus is on membrane stability at higher operating temperatures in a water ethanol mixture for sol–gel derived Hybsi® membranes and the membrane performance in pervaporation and vapour permeation. The stability of the membranes is one of the crucial factors of their application in industrial separation processes. A comparison between pervaporation and vapour permeation has been made in which water removal from ethanol has been used as an example. By applying higher temperatures and thus higher driving forces in the membrane unit the required membrane area and the total costs of the process are strongly reduced. The comparison was based on endurance tests, in the dehydration of ethanol at 150°C. The high hydrothermal and chemical stability of the membrane was proven in continuous measurements (24/7) that lasted for periods of over 500 days. The membrane performance was followed during this period of time by measuring the flux and membrane selectivity. Both in pervaporation and vapour permeation a good and stable membrane performance was obtained after a stabilisation period and from a flux and selectivity point of view at 150°C both membrane operation options show similar results. Detailed test results will be presented. For ethanol dehydration vapour permeation would be preferred above pervaporation as advantage can be taken of the vapour already present at the top of the distillation column which will still be used to remove major part of the water present. The presented results show that HybSi® membranes are applicable in the dehydration of ethanol by pervaporation and vapour permeation at higher temperatures. The high temperature use leads to a broadened application window and will open up markets that have so far been inaccessible for commercially available pervaporation and vapour permeation membranes

Application of four dyes in gene expression analyses by microarrays

BACKGROUND: DNA microarrays are widely used in gene expression analyses. To increase throughput and minimize costs without reducing gene expression data obtained, we investigated whether four mRNA samples can be analyzed simultaneously by applying four different fluorescent dyes. RESULTS: Following tests for cross-talk of fluorescence signals, Alexa 488, Alexa 594, Cyanine 3 and Cyanine 5 were selected for hybridizations. For self-hybridizations, a single RNA sample was labelled with all dyes and hybridized on commercial cDNA arrays or on in-house spotted oligonucleotide arrays. Correlation coefficients for all combinations of dyes were above 0.9 on the cDNA array. On the oligonucleotide array they were above 0.8, except combinations with Alexa 488, which were approximately 0.5. Standard deviation of expression differences for replicate spots were similar on the cDNA array for all dye combinations, but on the oligonucleotide array combinations with Alexa 488 showed a higher variation. CONCLUSION: In conclusion, the four dyes can be used simultaneously for gene expression experiments on the tested cDNA array, but only three dyes can be used on the tested oligonucleotide array. This was confirmed by hybridizations of control with test samples, as all combinations returned similar numbers of differentially expressed genes with comparable effects on gene expression

Synergistic Anticancer Effects of the 9.2.27PE Immunotoxin and ABT-737 in Melanoma

In cancer, combinations of drugs targeting different cellular functions is well accepted to improve tumor control. We studied the effects of a Pseudomonas exotoxin A (PE) - based immunotoxin, the 9.2.27PE, and the BH-3 mimetic compound ABT-737 in a panel of melanoma cell lines. The drug combination resulted in synergistic cytotoxicity, and the cell death observed was associated with apoptosis, as activation of caspase-3, inactivation of Poly (ADP-ribose) polymerase (PARP) and increased DNA fragmentation could be prevented by pre-treatment with caspase and cathepsin inhibitors. We further show that ABT-737 caused endoplasmic reticulum (ER) stress with increased GRP78 and phosphorylated eIF2α protein levels. Moreover, treatment with ABT-737 increased the intracellular calcium levels, an effect which was enhanced by 9.2.27PE, which as a single entity drug had minimal effect on calcium release from the ER. In addition, silencing of Mcl-1 by short hairpin RNA (shRNA) enhanced the intracellular calcium levels and cytotoxicity caused by ABT-737. Notably, the combination of 9.2.27PE and ABT-737 caused growth delay in a human melanoma xenograft mice model, supporting further investigations of this particular drug combination

Review of Electric Cracking of Hydrocarbons

The cracking of hydrocarbons is a highly energy-intensive process with large CO2 emissions. Industrial steam crackers use gas-fired furnaces, which produce a global CO2 emission of about 366 Mt/year. Modern crackers have been improved through the years to increase performance and reduce greenhouse emissions. However, the improvements are limited, and the required future CO2 emission reductions cannot be achieved with the present designs. Electrification is a promising option to make cracking processes more sustainable, especially if renewable electricity is used. Electric heating will result in energy savings as flue gas losses are avoided, while CO2 emissions will be reduced radically if renewable electricity is used. This paper evaluates the current state of electric cracking and identifies potential electric heating technologies for the electrification of cracking processes. Various electric heating technologies are reviewed, an extensive literature search is conducted on their application in cracking processes, and industrial applications of electric cracking are compiled. The study shows that resistance (Ohmic) heating is a promising electric heating technology for steam cracking of naphtha. The technology is relatively easy to scale up and can be used to retrofit existing crackers. The cost of electric cracking is expected to be higher than conventional cracking, mainly due to the current electricity price being higher than the gas price. However, the cost of naphtha represents about 80% of the ethylene production cost, so possible selectivity improvements could reduce the overall cost through lower feedstock consumption. The electrification of the cracking processes can be stimulated by guaranteeing sufficient availability of renewable electricity and by introducing a CO2 tax

Comparison of the efficiency of carbon dioxide capture by sorption-enhanced water-gas shift and palladium-based membranes for power and hydrogen production

Pre-combustion capture of carbon dioxide requires the industrial separation of carbon dioxide from hydrogen-rich streams. The present study analyses the thermodynamic efficiency penalty of this separation step and the achievable carbon capture ratio, with particular focus on high-temperature separation technologies: sorption-enhanced water–gas shift (SEWGS) and palladium membranes. Twelve different cases have been simulated, starting from coal-derived syngas or from natural gas derived reformate, using carbon dioxide capture by conventional absorption, SEWGS, and palladium membranes, and producing hydrogen-rich fuel for power production or pure hydrogen. For the production of decarbonised fuel from coal syngas, SEWGS always yields the lowest efficiency penalty per unit of carbon dioxide captured. For the production of pure hydrogen from coal syngas, SEWGS has a significantly higher carbon capture ratio than the alternatives while palladium membranes yield the lowest efficiency penalty per unit of carbon dioxide captured. For the production of decarbonised fuel from natural gas reformate, SEWGS is the most efficient technology in terms of efficiency penalty. For the production of pure hydrogen from natural gas syngas, palladium membranes yield the lowest efficiency penalty

96 week results from the MONET trial: A randomized comparison of darunavir/ritonavir with versus without nucleoside analogues, for patients with hiv RNA <50 copies/ml at baseline

Background: In virologically suppressed patients, switching to darunavir/ritonavir monotherapy could avoid resistance and adverse events from continuing nucleoside analogues. Methods: Two hundred and fifty-six patients with HIV RNA <50 copies/mL on current antiretrovirals were switched to darunavir/ritonavir 800/100 mg once daily, either as monotherapy (n=127) or with two nucleoside analogues (n=129). Treatment failure was defined as two consecutive HIV RNA levels at least 50 copies/mL by week 96, or discontinuation of study drugs. The trial had 80% power to show non-inferiority (δ=-12%) at week 48. Results: Patients were 81% male, 91% Caucasian, and had a median baseline CD4 count of 575 cells/mm. 3. There were more patients with hepatitis C co-infection at baseline in the monotherapy arm (18%) compared with the triple therapy arm (12%). In the efficacy analysis, HIV RNA <50 copies/mL by week 96 (per protocol, time to loss of virological response, switch equals failure) was 78% versus 82% in the monotherapy and triple therapy arms [difference -4.2%, 95% confidence interval (CI) -14.3% to +5.8%]; in a switch included analysis, HIV RNA <50 copies/mL was 93% versus 92% (difference +1.6%, 95% CI -5.0% to +8.1%). The percentage of patients with HIV RNA <5 copies/mL (optical density from the sample equal to the negative control) remained constant over time in both treatment arms. Conclusions: In the week 96 analysis of the MONotherapy in Europe with TMC114 (MONET) trial, switching to darunavir/ritonavir monotherapy showed non-inferior efficacy to darunavir/ritonavir plus two nucleoside analogues in the switch included and observed failure analyses, but not in the main switch equals failure analysis. © The Author 2011. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

HIV RNA suppression rates after 24 weeks of treatment with etravirine, darunavir/ritonavir and raltegravir in the etravirine early access programme

SCOPUS: le.jinfo:eu-repo/semantics/publishe