Analysis of a Filter Bag Reactor for gaseous pollution abatement

The conveying zone and the filter bag zone of a Filter Bag Reactor have been analysed as individual reactors. The gas and solid particles flow almost in plug flow through the pneumatic conveying section. In the filter bag the height of the packed column varies with time, a cell model has been used to calculate the concentration of outgoing stream. The total conversion obtained is the sum of conversions in each section of the reactor.

Separation of 5-methylcytosine-rich DNA using immobilized antibody

Anti-(5-methylcytosine) antibodies were immobilized on glutaraldehyde-activated Indion 48-R, a polystyrene resin with amino groups. Immobilized antibody was very stable and could be used several times without any apparent change in the initial binding capacity of the antibody-matrix. Fractions of total DNA from various animal and plant sources were retained on this column and could be eluted quantitatively with 1.0 m NaCl. The bound fraction was further characterized for its 5-methylcytosine content by restriction enzyme digestion patterns.

Studies on the fractionation of total transfer ribonucleic acid and purification of an alanine transfer ribonucleic acid from chick embryo

Chick embryo tRNA, prepared by a simple large-scale method, was fractionated on three different ion-exchange columns. In all cases simple chromatographic patterns for various tRNA species were observed, indicating the presence of only a few major species of tRNA for each amino acid. By repeated chromatography one species of alanine tRNA was purified to approx. 80% purity. T1 ribonuclease digest of this purified tRNA gave a simple chromatographic pattern. Because of the simplicity of the method of preparation of tRNA from this readily available source and the presence of only a few species of tRNA for each amino acid, chick embryo is suited for the study of tRNA and its various functions in higher systems.

Total photoproduction cross section at very high energy

In this paper we apply to the photoproduction total cross section a model we have proposed for purely hadronic processes and which is based on QCD mini-jets and soft gluon re-summation. We compare the predictions of our model with the HERA data as well as with other models. For cosmic rays, our model predicts substantially higher cross sections at TeV energies than models based on factorization, but lower than models based on mini-jets alone, without soft gluons. We discuss the origin of this difference.

Separation of 35S-Labeled thionucleosides of Escherichia coli and Pseudomonas aeruginosa transfer RNAs on a phosphocellulose column

35S-Labeled thionucleosides prepared from Escherichia coli and Pseudomonas aeruginosa tRNAs were chromatographed separately on a phosphocellulose column with a linear salt gradient of 0.005–0.1 M ammonium formate (pH 3.9). The thionucleosides of E. coli tRNA were quantitatively separated into four peaks which were identified using authentic samples as 4-thiouridine (78 %), 2-methylthio-N6-isopentenyladenosine (8 %), 2-thiocytidine (2.5 %) and 5-methylaminomethyl-2-thiouridine (11.5 %). In the case of P. aeruginosa tRNA four radioactive thionucleoside peaks were also observed. One major difference was the almost complete absence of 2-methylthio-N6-isopentenyladenosine and the presence of a new peak of radioactivity in the nucleosides of P. aeruginosa. The relative proportions of the various thionucleosides were found to be different in E. coli and P. aeruginosa tRNAs.

Improvement in the voltage grading (axial and radial) of the generator column of a Van de Graaf generator by the use of a resistor chain

It is well known that the use of a series of resistors, connected between the equipotential rings of a Van de Graaff generator, improves the axial voltage grading of the generator. The work reported in this paper shows how the resistor chain also improves the radial voltage gradient. The electrolytic field mapping technique was adopted in the present work.

Specific polyadenylation and purification of total messenger RNA from Escherichia coli

Obtaining pure mRNA preparations from prokaryotes has been difficult, if not impossible, for want of a poly(A) tail on these messages, We have used poly(A) polymerase from yeast to effect specific polyadenylation of Escherichia coli polysomal mRNA in the presence of magnesium and manganese, The polyadenylated total mRNA, which could be subsequently purified by binding to and elution from oligo(dT) beads, had a size range of 0.4-4.0 kb. We have used hybridization to a specific plasmid-encoded gene to further confirm that the polyadenylated species represented mRNA, Withdrawal of Mg2+ from the polyadenylation reaction rRNA despite the presence of Mn2+, indicating the vital role of Mg2+ in maintaining the native structure of polysomes, Complete dissociation of polysomes into ribosomal subunits resulted in quantitative polyadenylation of both 16S and 23S rRNA species, Chromosomal lacZ gene-derived messages were quantitatively recovered in the oligo(dT)-bound fraction, as demonstrated by RT-PCR analysis, Potential advantages that accrue from the availability of pure total mRNA from prokaryotes is discussed.

Solid phase fermentation of leaf biomass to biogas

This paper describes a simple technique for the fermentation of untreated or partly-treated leafy biomass in a digester of novel design without incurring the normal problems of feeding, floating and scum formation of feed, etc. The solid phase fermentation studied consists of a bed of biomass frequently sprinkled with an aqueous bacterial inoculum and recycling the leachate to conserve moisture and improve the bacterial dispersion in the bed. The decomposition of the leaf biomass and water hyacinth substrates used in this study was rapid, taking 45 and 30 days for the production of 250 and 235 l biogas per kg total solids (TS) respectively, for the above mentioned substrates at a daily sprinkled volume of 26 ml cm−2 of bed per day sprinkled at 12 h intervals. Very little volatile fatty acid (VFA) intermediates accumulated in the liquid sprinkled, suggesting acidogenesis to be rate-limiting in this process. From the pattern of VFA and gas produced it is concluded that most of the biogas produced is from the biomass bed, thus making the operation of a separate methanogenic reactor unnecessary.

Light- and cytokinin-induced changes in the levels of leucine and tyrosine isoaccepting tRNA species and modified nucleotide contents of total tRNA in cucumber seedlings

We have determined relative levels of chloroplast leucine and tyrosine isoaccepting tRNAs and modified nucleotide contents from total tRNAs isolated from dark-grown, light-grown, N6-isopentenyladenine (i6A)-treated dark-grown and i6A-treated light-grown cucumber seedlings. Significant increases in the relative amounts of tRNA(Leu)2 and tRNA(Leu)3 were observed in the i6A-treated dark-grown seedlings compared to dark-grown, light-grown and i6A-treated light-grown seedlings. On the other hand, i6A-treated light-grown seedlings tRNA(Tyr)1 increased to 85% of total tRNAs(Tyr) from about 9% in light-grown seedlings and tRNA(Tyr)2 decreased to 15% compared with 91% in light-grown seedlings. Analysis of modified nucleotide of total tRNAs indicated that pT, pI, pm1A, pm5C, pGm, pm1G, pm2G and pm7G contents were significantly higher in the total tRNA of i6A-treated dark-grown seedlings than those from untreated dark-grown seedlings. Illumination of 8-day-old dark-grown seedlings for 12 h increased the contents of pT, pI, pGm and pm1G when compared to 8-day-old dark-grown seedlings with extended growth for 12 h in dark. On the contrary, i6A had no stimulatory effect in the contents of modified nucleotide in the light-grown seedlings.

Intensity Oscillation in the Corona as Observed during the Total Solar Eclipse of 29 March 2006

We obtained the images of the eastern part of the solar corona in the Fe xiv 530.3 nm (green) and Fe x 637.4 nm (red) coronal emission lines during the total solar eclipse of 29 March 2006 at Manavgat, Antalya, Turkey. The images were obtained using a 35 cm Meade telescope equipped with a Peltier-cooled 2k x 2k CCD and 0.3 nm pass-band interference filters at the rates of 2.95 s (exposure times of 100 ms) and 2.0 s (exposure times of 300 ms) in the Fe xiv and Fe x emission lines,respectively. The analysis of the data indicates intensity variations at some locations with period of strongest power around 27 s for the green line and 20 s for the red line. These results confirm earlier findings of variations in the continuum intensity with periods in the range of 5 to 56 s by Singh et al. (Solar Phys. 170, 235, 1997). The wavelet analysis has been used to identify significant intensity oscillations at all pixels within our field of view. Significant oscillations with high probability estimates were detected for some locations only. These locations seem to follow the boundary of an active region and in the neighborhood, rather than within the loops themselves. These intensity oscillations may be caused by fast magneto-sonic waves in the solar corona and partly account for heating of the plasma in the corona.

Stereoselective Formal Total Synthesis of (-)-Didemniserinolipid B

A formal total synthesis of (-)-didemniserinolipid B from L-(+)-tartaric acid is presented. Key features of the synthesis include construction of the bicyclic acetal core from bisdimethyl amide of tartaric acid and further elaboration by cross metathesis.

Identification and characterization of thionucleosides in the total tRNA of cucumber cotyledons

Total tRNA isolated from cucumber cotyledons grown in the presence of radioactive sulfur was analyzed for the occurrence of thionucleosides. The analysis revealed the presence of at least five thionucleosides which were identified as 5-methylaminomethyl-2-thiouridine (mnm5s2U), 2-methylthio-N6-isopentenyladenosine (ms2i6A), 2-methylthio-N6-hydroxyisopentenyladenosine (ms2io6A), 5-methyl-2-thiouridine (m5s2U) and N-[(9-beta-ribofuranosyl-2- methylthiopurine-2-yl)-carbamoyl]-threonine (ms2t6A). A comparison of relative amounts of these thionucleosides in the total tRNAs of dark-, and light-grown cotyledons shows that the relative amounts of ms2i6A, ms2io6A and ms2t6A remain unchanged whereas mnm5s2U increases with a concomitant decrease in the relative amounts of m5s2U after light treatment of dark-grown cotyledons.

Asymmetric total synthesis of erythromycin. 2. Synthesis of an erythronolide A lactone system

In reporting a total synthesis of erythromycin (la) we described in the preceding paper1 the synthesis of the erythronolide A seco acid derivative 2 in optically active form. In this paper we wish to report a successful transformation of 2 to 12 (synthetically equivalent to erythronolide A) via lactonization and also demonstrate that the proper functionalization of a substrate is critical for the successful lactonization.

Asymmetric total synthesis of erythromycin. 3. Total synthesis of erythromycin

In the preceding paper' we described the preparation of the key lactone intermediate la in optically active form. In this paper we report the synthesis of erythromycin (2) from la. In essence,this transformation involves the glycosidation of a suitable derivative of la with L-cladinose and D-desosamine and the generation of the C-9 ketone functionality.