Separation of glycerol from FAME using ceramic membranes

International standards (e.g., ASTM D6751 and EN14214) limit the presence of free glycerol in biodiesel. The traditional water wash method for removing glycerol from crude fatty acid methyl esters (FAME) obtained in the production of biodiesel results in waste waters that cannot be readily discharged. To circumvent the water wash purification method, a membrane separation system using ceramic membranes was designed, constructed and tested for the removal of glycerol from crude FAME from a biodiesel production process. Ceramic membranes in the ultrafiltration (0.05 μm) and microfiltration (0.2 μm) ranges were tested at three different operating temperatures: 0, 5 and 25 °C. All runs separated glycerol from the crude FAME. International standards for glycerol content in biodiesel were met after 3 h when utilizing the ultrafiltration membrane setup at 25 °C with a concentration factor greater than 1.6.     

Purification and crystallization of complexes modeling the active state of the fragile histidine triad protein

Fragile histidine triad protein (Fhit) is a diadenosine triphosphate (ApppA) hydrolase encoded at the human chromosome 3 fragile site which is frequently disrupted in tumors. Reintroduction of FHIT coding sequences to cancer cell lines with FHIT deletions suppressed the ability of these cell lines to form tumors in nude mice even when the reintroduced FHIT gene had been mutated to allow ApppA binding but not hydrolysis. Because this suggested that the tumor suppressor activity of Fhit protein depends on substrate-dependent signaling rather than ApppA catabolism, we prepared two crystalline forms of Fhit protein that are expected to model its biologically active, substrate-bound state. Wild-type and the His96Asn forms of Fhit were overexpressed in Escherichia coli, purified to homogeneity and crystallized in the presence and absence of ApppA and an ApppA analog. Single crystals obtained by vapor diffusion against ammonium sulfate diffracted X-rays to beyond 2.75 A resolution. High quality native synchrotron X-ray data were collected for an orthorhombic and a hexagonal crystal form.      

Improvement in polyetherimide gas separation membranes through the incorporation of nanostructured metal complexes

Polyetherimide (PEI) gas separation membranes were tailored, at the molecular scale, by the incorporation of nanostructured metallic complexes into the PEI network. The influence of these additives on the micropore size distributions of the membranes produced and on their performance for oxygen/nitrogen separation was investigated. Changing the metal within the same ligand had a significant influence on the microporosity and gas separation performance of these membranes. Magnesium (II) phathalocyanine (MgPc) in PEI membranes was found to be an excellent additive to increase membrane performance for air separation. The performance of these membranes increases with increasing additive concentrations. Membranes with this additive also exhibit an improved stability as determined through the annealing process. Annealing these membranes caused a slight decrease in their gas permeance and total micropore volume but a significant increase in their gas selectivity. The results show that the properties of the nanophase additive and nanophase-polymer interactions play a pivotal role in stabilizing and determining membrane performance for air separation.     

Proton conductivity and morphology of new composite membranes based on zirconium phosphates,phosphotungstic acid,and silicic acid for direct hydrocarbon fuel cells applications

The effect of Phosphotungstic acid (PWA) on the proton conductivity and morphology of zirconium phosphate (ZrP), porous polytetrafluoethylene (PTFE), glycerol (GLY) composite membrane was investigated in this work. The composite membranes were synthesized using two approaches: (1) Phosphotungstic acid (PWA) added to phosphoric acid and, (2) PWA + silicic acid were added to phosphoric acid. ZrP was formed inside the pores of PTFE via the in situ precipitation. The membranes were evaluated for their morphology and proton conductivity. The proton conductivity of PWA–ZrP/PTFE/GLY membrane was 0.003 S cm^?1. When PWA was combined with silicic acid, the proton conductivity increased from 0.003 to 0.059 S cm^?1 (became about 60% of Nafion’s). This conductivity is higher than the proton conductivity of Nafion–silica–PWA membranes reported in the literature. The SEM results showed a porous structure for the modified membranes. The porous structure combined with this reasonable proton conductivity would make these membranes suitable as the electrolyte component in the catalyst layer for direct hydrocarbon fuel cell applications.     

Distribution of soap in a membrane reactor in the production of fame from waste cooking oil

A continuous‐flow membrane reactor was constructed for the production of fatty acid methyl ester (FAME) from waste vegetable oil with high free fatty acid (FFA) content. FAME was produced via base‐catalysed transesterification with methanol at two FFA levels: 4.8 and 10 mass%. The effect of the ceramic membrane pore size on the separation of soap and triglycerides from the FAME in the reactor was investigated. In all cases, the triglyceride was completely retained in the reactor, yielding free and total glycerine contents in the produced FAME significantly below the maximum limits of the ASTM D6751 standard. The soaps produced in the reaction mixture were not completely retained in the reactor and did not affect the FAME production process. © 2012 Canadian Society for Chemical Engineering     

Functional EGFP-dystrophin fusion proteins for gene therapy vector development

Transfection and transduction studies involving the use of thefull-length dystrophin (11 kb) or the truncated mini-gene (6kb) cDNAs are hampered by the large size of the resulting viralor non-viral expression vectors. This usually results in verylow yields of transgene-expressing cells. Moreover, the detectionof the few transgene-expressing cells is often tedious and costly.For these reasons, expression vectors containing the enhancedgreen fluorescent protein (EGFP) fused with the N-termini ofmini- and full-length human dystrophin were constructed. Theseconstructs were tested by transfection of Phoenix cells withEffectene, resulting after 48 h in a green fluorescent signalin 20% of cells. Analysis of the cell extracts by immunoblottingwith the use of a monoclonal antibody specific to the dystrophinC-terminus confirmed the expression of EGFP–mini- (240kDa) and EGFP–full-length human dystrophin (450 kDa) fusionproteins. Moreover, following the in vivo electroporation ofthe plasmids containing the EGFP–mini- and full-lengthdystrophin in mouse muscles, both fluorescent proteins wereobserved in cryostat sections in their normal location underthe plasma membrane. This indicates that the fusion of EGFPto dystrophin or mini-dystrophin did not interfere with thenormal localization of the protein. In conclusion, the fusionof EGFP provides a good tool for the search of the best methodsto introduce mini- or full-length dystrophin cDNA in the cells(in vitro) or muscle fibers (in vivo) for the establishmentof a treatment by gene therapy of Duchenne muscular dystrophypatients.     

Timothy hay with a low dietary cation-anion difference improves calcium homeostasis in periparturient Holstein cows

The current study was undertaken to evaluate the effects of feeding timothy (Phleum pratense L.) hay differing in dietary cation-anion difference (DCAD) on the capability of cows to maintain calcium homeostasis around parturition. We hypothesized that feeding low-DCAD timothy hay during the prepartum period would induce a mild metabolic acidosis prepartum and improve calcium homeostasis postpartum with no effect on dry matter intake. Forty-one dry pregnant Holstein cows entering their second lactation or greater were used in a randomized complete block design. Timothy hay was obtained from an established timothy stand under a pivot irrigation system. Low-DCAD timothy hay was produced by fertilizing the area between the second and third pivot towers at a rate of 224 kg of CaCl₂/ha, and control timothy hay (high DCAD) was grown on the area between the fourth and fifth pivot towers of the same field. The chloride concentration was 1.07 and 0.15% on a dry matter (DM) basis, and the DCAD was 1.2 and 21.6 mEq/100 g of DM for the low- and high-DCAD timothy hay, respectively. Experimental diets, containing timothy hay at 63% of dietary DM, were fed ad libitum starting 30 d before the expected calving date. The DCAD values were 1.6 vs. 14.5 mEq/100 g of DM for the low- and high-DCAD timothy-based diets, respectively. At the beginning of the study, urine pH and blood bicarbonate concentration averaged 8.22 ± 0.06 and 28.5 ± 0.3 mM, respectively. The low-DCAD timothy diet decreased urine pH compared with the high-DCAD timothy diet on d 21 (7.75 vs. 8.31), d 14 (7.69 vs. 8.22), and d 7 (7.50 vs. 8.19) before calving, and it also decreased the prepartum blood bicarbonate concentration by 2 mM. In addition, cows fed the low-DCAD timothy diet had greater blood ionized calcium concentration prepartum (1.22 vs. 1.19 mM), greater blood ionized calcium concentration at 0 and 8 h after calving, and similar prepartum dry matter intake. These results indicate that timothy hay differing in DCAD affects the acid-base balance of periparturient dairy cows, and that low-DCAD timothy hay improves calcium homeostasis postpartum with no negative effect on dry matter intake.     

"Cognitive-neuropsychological function in chronic physical aggression and hyperactivity": Correction to Séguin et al. (2004).

Reports an error in "Cognitive-Neuropsychological Function in Chronic Physical Aggression and Hyperactivity" by Jean R. Séguin, Daniel Nagin, Jean-Marc Assaad and Richard E. Tremblay (Journal of Abnormal Psychology, 2004[Nov], Vol 113[4], 603-613). The use of a weighted procedure within SAS PROC GLM inflated F statistics and underestimated standard errors that affected only conclusions from secondary analyses that were drawn about the specificity of working memory effects to physical aggression and hyperactivity. The corrected conclusions are presented in the erratum. The last two sentences of the abstract also needed to be corrected in order to reflect the new conclusions. The corrected sentences appear in the erratum as well. (The following abstract of the original article appeared in record 2004-20178-011.) Histories of violence and of hyperactivity are both characterized by poor cognitive-neuropsychological function. However, researchers do not know whether these histories combine in additive or interactive ways. The authors tested 303 male young adults from a community sample whose trajectories of teacher-rated physical aggression and motoric hyperactivity from kindergarten to age 15 were well defined. No significant interaction was found. In a 1st model, both histories of problem behavior were independently associated with cognitive-neuropsychological function in most domains. In a 2nd model controlling for IQ, general memory, and test motivation, the 3 working-memory tests (relevant to executive function) remained associated with physical aggression, and 1 remained associated with hyperactivity. These results support an additive model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimal and heuristic solution methods for a multiprocessor machine scheduling problem

This paper deals with the scheduling of operations on a multiprocessor machine in the context of shoe manufacturing. Multiprocessor machines are composed of several parallel processors. Unlike parallel machines, the entire machine needs to be stopped whenever a single processor needs a setup. Our industrial partner, one of the major winter-shoe manufacturers in Canada, offers a relatively large variety of models. For each of these models, all the sizes proposed by this manufacturer must be produced in various quantities. Our objective is to schedule the production of the required sizes on the machine's different processors in order to minimize the global makespan, which includes both the production time and the set up time. We first present a mathematical formulation of the problem. Then, we introduce a decomposition procedure based on the mathematical model, and we demonstrate that this procedure is very efficient for small- and medium-size instances. We also propose two construction heuristics and two improvement heuristics for larger problems, and we report the results of our extensive computational experiments to demonstrate the quality of the proposed heuristics in terms of reducing production time and computational effort.     

Architecture and Physical Implementation of a Third Generation 65 nm, 16 Core, 32 Thread Chip-Multithreading SPARC Processor

This third-generation Chip-Multithreading (CMT) SPARC processor consists of 16 cores with shared memory architecture and supports a total of 32 main threads plus 32 scout threads. It is targeted for high-performance servers, and is optimized for both single- and multi-threaded applications. The 396 mm² chip is fabricated in an 11 metal layer 65-nm CMOS process and operates at a nominal frequency of 2.3 GHz, consuming a maximum power of 250 W at 1.2 V. This paper provides an overview of the architectural highlights and describes the physical implementation challenges and solutions including circuit innovations in memory arrays, register files, and floating-point hardware that boost the performance and circuit robustness with low area overhead.