The continuous combustion of glycerol in a fluidised bed

It is difficult to burn a liquid fuel inside a fluidised bed. For the first time, liquid glycerol has been burned, when continuously injected into the bottom of an electrically heated bed of alumina particles (sieved to 355 – 425 μm), fluidised by air. The temperature in the bed was held at 700, 800 or 900oC; usually (U/Umf) was 2.5. The bed’s depth was varied, as also were (U/Umf) and the ratio of fuel to air supplied to the bed. Measurements were made of the concentrations of CH4, O2, CO and CO2, and also of the temperature, in the freeboard well above the bed. On entering the bed, the liquid glycerol, rapidly formed bubbles of vapour, which quickly decomposed thermally, yielding mostly CO and H2. These gases then mixed with the other gases in the bed. It appears that the diffusive H2 mainly burns between the fluidised particles. With the bed at 700 – 900oC, no CO was detected far downstream of the bed, provided the equivalence ratio, θ, was below 0.7, i.e. with more than 43 % excess air. Under these fuel-lean conditions, all the carbon in the glycerol was oxidised to CO2. However, in a more fuel-rich situation, with θ > 0.7, CO was detected well above the bed, particularly with a deeper bed, at a lower temperature and operating more fuel-rich. Thus, with the bed at 900oC, CO was mostly oxidised inside the bed, but occasionally some CO burned on top of the bed. When a fuel-rich bed was below 850oC, not all the CO burned in the bed. Achieving complete combustion inside a fluidised bed is partly a problem of mixing the products of glycerol’s thermal decomposition with the fluidising air, which on entry exists mainly in bubbles. Consequently, increasing (U/Umf) promoted both mixing and combustion in a bed. In addition, in-bed combustion requires the bed to be sufficiently deep, hotter than 850oC and θ to be less than a critical value. The effects of other variables are discussed

First-principles study of phase stability of Gd-doped EuO and EuS

Phase diagrams of isoelectronic Eu$_{1-x}$Gd$_x$O and Eu$_{1-x}$Gd$_{x}$S quasi-binary alloy systems are constructed using first-principles calculations combined with the standard cluster expansion approach and Monte-Carlo simulations. The oxide system has a wide miscibility gap on the Gd-rich side but forms ordered compounds on the Eu-rich side, exhibiting a deep asymmetric convex hull in the formation enthalpy diagram. The sulfide system has no stable compounds. The large difference in the formation enthalpies of the oxide and sulfide compounds is due to the contribution of local lattice relaxation, which is sensitive to the anion size. The solubility of Gd in both EuO and EuS is in the range of 10-20% at room temperature and quickly increases at higher temperatures, indicating that highly doped disordered solid solutions can be produced without the precipitation of secondary phases. We also predict that rocksalt GdO can be stabilized under appropriate experimental conditions.Comment: 14 pages, 6 figures (some with multiple panels), revtex4 with embedded ep

Cellular gene delivery via poly(hexamethylene biguanide)/pDNA self-assembled nanoparticles

Cellular gene delivery via polycations has wide implications for the potential of gene therapy, but it has remained a challenge due to the plethora of pre- and post-uptake barriers that must be overcome to reach desired efficiency. Herein we report poly(hexamethylene biguanide) (PHMB) as a nano-vector for intracellular delivery of plasmid DNA (pDNA) and oligodeoxynucleotides (ODNs). PHMB and pDNA or ODNs self-assembled into complex nanoparticles at different pH values (7.4 and 12). Their size, charge, cellular uptake, and gene-expression efficiency are assessed and compared to PEI analogues. The systematic results show that the nanoparticles are effective in delivering plasmid DNA and ODNs to model cell lines in culture (HepG2, HEK293T, HeLa), with measurable changes in gene expression levels, comparable to and, in some conditions, even higher than PEI. The well-accepted safety profile of PHMB makes it a valuable candidate for consideration as an effective intracellular DNA vector for further study and potential clinical translation

Bounds on R-Parity Violating Parameters from Fermion EDM's

We study one-loop contributions to the fermion electric dipole moments in the Minimal Supersymmetric Standard Model with explicit R-parity violating interactions. We obtain new individual bounds on R-parity violating Yukawa couplings and put more stringent limits on certain parameters than those obtained previously.Comment: 16 pages, LaTe

Should patients with kearns-sayre syndrome and corneal endothelial failure be genotyped for a TCF4 trinucleotide repeat, commonly associated with fuchs endothelial corneal dystrophy?

The aim of this study was to describe the ocular phenotype in a case with Kearns-Sayre syndrome (KSS) spectrum and to determine if corneal endothelial cell dysfunction could be attributed to other known distinct genetic causes. Herein, genomic DNA was extracted from blood and exome sequencing was performed. Non-coding gene regions implicated in corneal endothelial dystrophies were screened by Sanger sequencing. In addition, a repeat expansion situated within an intron of TCF4 (termed CTG18.1) was genotyped using the short tandem repeat assay. The diagnosis of KSS spectrum was based on the presence of ptosis, chronic progressive external ophthalmoplegia, pigmentary retinopathy, hearing loss, and muscle weakness, which were further supported by the detection of ~6.5 kb mtDNA deletion. At the age of 33 years, the proband’s best corrected visual acuity was reduced to 0.04 in the right eye and 0.2 in the left eye. Rare ocular findings included marked corneal oedema with central corneal thickness of 824 and 844 µm in the right and left eye, respectively. No pathogenic variants in the genes, which are associated with corneal endothelial dystrophies, were identified. Furthermore, the CTG18.1 genotype was 12/33, which exceeds a previously determined critical threshold for toxic RNA foci appearance in corneal endothelial cells

Sitagliptin is effective and safe as add-on to insulin in patients with absolute insulin deficiency: a case series

<p>Abstract</p> <p>Introduction</p> <p>It is generally believed that incretin-based therapies are effective in patients possessing certain levels of preserved β-cell function. So far, there are no reports that show the effectiveness of dipeptidyl peptidase-4 inhibitors in patients who absolutely lack the capacity for endogenous insulin secretion.</p> <p>Case presentation</p> <p>This report describes the efficacy of sitagliptin in three Japanese patients (a 91-year-old Japanese woman with type 1 diabetes, a 54-year-old Japanese man with type 2 diabetes and a 30-year-old Japanese man with features of both type 1 and type 2 diabetes) who had no detectable post-meal C-peptide levels. Although they were receiving intensive insulin therapy together with some oral hypoglycemic agents, their glycemic control remained poor. Sitagliptin was added to the ongoing therapeutic regimen to provide better glycemic control. Although these patients had mild hypoglycemia, effective reductions of hemoglobin A1c levels were observed without any adverse events in the liver and kidney during the following 24 weeks. Two of the patients were able to reduce their insulin doses, and one of the patients could discontinue one of the oral hypoglycemic agents. There was no weight gain or gastrointestinal complaints among the three patients. Post-meal C-peptide levels remained undetectable after sitagliptin treatment.</p> <p>Conclusion</p> <p>This report demonstrates that sitagliptin is effective and safe as an add-on therapy to insulin in reducing blood glucose levels in patients who absolutely lack the capacity for endogenous insulin secretion. The improvement seen in glycemic control could not be due to enhanced endogenous insulin secretion, since post-meal C-peptide levels remained undetectable after sitagliptin treatment, but it could be a result of other factors (for example, suppression of glucagon levels). However, the glucagon-suppressive effect of sitagliptin is known to be rather weak and short-lived. Given this background, a novel hypothesis that the glycemic effects of this drug may be caused by mechanisms that are independent of the glucagon-like peptide 1 axis (extra-pancreatic effect) will be discussed.</p

Implementation of a hybrid particle code with a PIC description in r-z and a gridless description in phi into OSIRIS

For many plasma physics problems, three-dimensional and kinetic effects are very important. However, such simulations are very computationally intensive. Fortunately, there is a class of problems for which there is nearly azimuthal symmetry and the dominant three-dimensional physics is captured by the inclusion of only a few azimuthal harmonics. Recently, it was proposed [1] to model one such problem, laser wakefield acceleration, by expanding the fields and currents in azimuthal harmonics and truncating the expansion. The complex amplitudes of the fundamental and first harmonic for the fields were solved on an r–z grid and a procedure for calculating the complex current amplitudes for each particle based on its motion in Cartesian geometry was presented using a Marder's correction to maintain the validity of Gauss's law. In this paper, we describe an implementation of this algorithm into OSIRIS using a rigorous charge conserving current deposition method to maintain the validity of Gauss's law. We show that this algorithm is a hybrid method which uses a particles-in-cell description in r–z and a gridless description in ?. We include the ability to keep an arbitrary number of harmonics and higher order particle shapes. Examples for laser wakefield acceleration, plasma wakefield acceleration, and beam loading are also presented and directions for future work are discussed.info:eu-repo/semantics/submittedVersio