bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasmid stability in a recombinant S cerevisiae strain secreting a bifunctional fusion protein
Authors: Altıntaş M Mete , Kırdar Betül , Önsan Z İlsen , Ülgen Kutlu Ö
Published: January 2005

The recombinant Saccharomyces cerevisiae strain, YPB‐G, producing and secreting Bacillus subtilis α‐amylase and Aspergillus awamori glucoamylase as a fusion protein yielded efficient utilisation of starch. A segregated population balance model has been used to determine the probability of plasmid loss and plasmid copy number. The kinetics of cell growth and product (fusion protein) formation were based on a genetically structured model. The predictions were compared with the experimental observations obtained for the unstable recombinant S cerevisiae cells in a 1.5 dm−3 batch bioreactor with 30 g dm3 initial starch under non‐aerated conditions. The main advantage of the present model is that three different genetic classes were defined on the basis of the existence of plasmid and of the expression of the enzymes, ie cells containing plasmids and expressing the gene product, x1; cells containing plasmids and but not expressing the gene product, x2; and cells without plasmids, x3. It is confirmed by this model that the cells without plasmids outgrow and dominate in the fermentation medium (2.27 g dm−3 vs 0.51 g dm−3) as more and more glucose becomes available by the degradation of starch.

© 2001 Society of Chemical Industry
Production of p‐toluenesulfonic acid by sulfonating toluene with gaseous sulfur trioxide
Authors: Wu J C , Wang B H , Zhang D L , Song G F , Yuan J T , Liu B F
Published: January 2005

Toluene was sulfonated by gaseous sulfur trioxide to prepare p‐toluenesulfonic acid. The effects of reaction temperature and toluene conversion on the isomer selectivities and the dynamic viscosity of the reaction mixture in a well‐stirred tubular glass reactor of 4 cm diameter and 16 cm height were investigated. Lower selectivity to the m‐isomer was obtained at lower reaction temperature and lower conversion of toluene, whereas the selectivity to the p‐isomer seemed to be less affected by these parameters. With the increase in toluene conversion a sharp increase in viscosity of the reaction mixture was observed, which was attributed to the saturation of the toluenesulfonic acids dissolved in toluene. A pilot‐scale stainless steel jet loop reactor (JLR) of 0.3 m diameter and 4 m height with an external cooler was constructed and used for the continuous sulfonation of toluene. It was found that the JLR was very effective for the fast removal of the large amount of reaction heat, and selectivities to the p‐isomer around 85% and to the m‐isomer below 1.2% were obtained.

© 2001 Society of Chemical Industry
Application of the accelerated shelf life testing method (ASLT) to study the survival rates of freeze‐dried Lactococcus starter cultures
Authors: Achour M , Mtimet N , Cornelius C , Zgouli S , Mahjoub A , Thonart Ph , Hamdi M
Published: January 2005

The survival rates of two freeze‐dried strains, Lactococcus lactis var diacetylactis and Lactococcus lactis var lactis, were evaluated using the Accelerated Shelf Life Testing (ASLT) method. The strains were initially isolated from a brand of a Tunisian fermented milk product. Lactococcus cell survival observed at higher temperatures was used to extrapolate to shelf life at a lower storage temperature of 4 °C. The apparent kinetics of the survival rate loss were estimated and the effect of storage temperature was quantified by determining the inactivation energies for various samples. The work has shown an overall higher survival rate of the strain Lactococcus lactis var diacetylactis. An average half‐life of a strain maintained at 25 °C was equal to about 7 days as compared with about 43 days at 4 °C. The addition of lyoprotectants such glycerol, saccharose and calcium carbonate to the drying medium, improved the survival of such bacteria.

© 2001 Society of Chemical Industry
Diffusional properties of chitosan hydrogel membranes
Authors: Krajewska Barbara
Published: January 2005

Chitosan membranes were prepared by a solvent evaporation technique, followed by crosslinking with glutaraldehyde and coating with BSA. The effects of crosslinking and BSA coating on the pore structure of such prepared hydrogel chitosan membranes were determined. The diffusion rates of 12 non‐electrolytes ranging in molecular radius between 2.5 and 14 Å through the membranes were measured, and the results were interpreted in terms of the capillary pore model and free volume model of solute diffusional transport through hydrogel membranes. Glutaraldehyde crosslinking was found to reduce the membrane water content and consequently the membrane pore size and surface porosity, whereas further BSA coating brought about the opposite effect. The latter effect lessened with an increase in glutaraldehyde pretreatment of the membranes. The optimal chitosan membrane preparation, compromising between the solute flux and membrane stability and durability was obtained when the membranes were crosslinked with glutaraldehyde at concentrations between 0.01 and 0.1% (w/w). The knowledge of transport properties and of physical strength of the membranes is of importance for the development of chitosan‐based controlled release systems.

© 2001 Society of Chemical Industry
Determination of potential methane production capacity of a granular sludge from a pilot‐scale upflow anaerobic sludge blanket reactor using a specific methanogenic activity test
Authors: Ince Orhan , Ince Bahar Kasapgil , Yenigun Orhan
Published: January 2005

A 450 dm3 pilot‐scale upflow anaerobic sludge blanket (UASB) reactor was used for the treatment of a fermentation‐based pharmaceutical wastewater. The UASB reactor performed well up to an organic loading rate (OLR) of 10.7 kg COD m−3 d−1 at which point 94% COD removal efficiency was achieved. This high treatment efficiency did not continue, however and the UASB reactor was then operated at lower OLRs for the remainder of the study. Specific methanogenic activity (SMA) tests were, therefore, carried out to determine the potential loading capacity of the UASB reactor. For this purpose, the SMA tests were carried out at four different initial acetate concentrations, namely 500 mg dm−3, 1000 mg dm−3, 1500 mg dm−3 and 2000 mg dm−3 so that substrate limitation could not occur. The results showed that the sludge sample taken from the UASB reactor (OLR of 6.1 kg COD m−3 d−1) had a potential acetoclastic methane production (PMP) rate of 72 cm3 CH4 g−1 VSS d−1. When the PMP rate was compared with the actual methane production rate (AMP) of 67 cm3 CH4 g−1 VSS d−1 obtained from the UASB reactor, the AMP/PMP ratio was found to be 0.94 which ensured that the UASB reactor was operated using its maximum potential acetoclastic methanogenic capacity. In order to achieve higher OLRs with desired COD removal efficiencies it was recommended that the UASB reactor should be loaded with suitable OLRs pre‐determined by SMA tests.

© 2001 Society of Chemical Industry
Activity of horseradish peroxidase in aqueous and reverse micelles and back‐extraction from reverse‐micellar phases
Authors: Motlekar Nuzhat A , Bhagwat Sunil S
Published: January 2005

Studies on the activity of the enzyme horseradish peroxidase (HRP) have been carried out in micellar as well as reverse‐micellar media. The activity of the enzyme was studied in the presence of different classes of surfactants – ionic as well as non‐ionic. In aqueous media, the activity of the enzyme varied depending on whether the concentration of the surfactant used was above or below the critical micellar concentration (CMC). The enzyme was also studied in reverse‐micellar systems. HRP was introduced into the reverse micellar phase by the injection method and its activity within the reverse micelles was determined. The effect of water to surfactant ratio (Wo) on activity within reverse micelles was studied, and an almost two‐fold increase in activity was seen when the enzyme was encapsulated within reverse micelles of aqueous phase fractional hold‐up (ϕ) of 0.0072 (v/v) consisting of sodium bis‐(2‐ethylhexyl) sulfosuccinate (AOT) in isooctane at a Wo of 20. The activity of HRP was measured over a wide range of AOT concentrations having different Wo values. Back‐extraction of HRP from these reverse micelles was carried out at varying ionic strengths of phosphate buffer. Back extraction was found to be highest at pH 7.0 in 40 mol m−3 phosphate buffer and 100 mol m−3 sodium chloride.

© 2001 Society of Chemical Industry
Hydrolysis of p‐nitrophenyl laurate in supercritical carbon dioxide: comparison of two different enzymes
Authors: Srivastava Shireesh , Madras Giridhar
Published: January 2005

The enzymatic hydrolysis of p‐nitrophenyl laurate (PNPL) to p‐nitrophenol (PNP) was studied in supercritical carbon dioxide using crude Hog Pancreas Lipase (HPL) and P roqueforti Lipase (PRL). The two enzymes were compared for their optimal activity temperatures and reaction kinetics. HPL had a higher optimal temperature (65 °C) and better yield (22.5%) compared with PRL whose optimal temperature was 50 °C with a 15.3% yield. This is considerably higher than the optimum temperature of 37 °C and yields of less than 1% observed in the aqueous medium.

© 2001 Society of Chemical Industry
Dual solute adsorption of 2,4,6‐trichlorophenol and N‐[2‐(2,4,6‐trichlorophenoxy)propyl]amine on to activated carbon
Authors: Garner Ian A , Watson‐Craik Irene A , Kirkwood Ralph , Senior Eric
Published: January 2005

The capacities of four activated carbon types to adsorb both 2,4,6‐trichlorophenol (TCP) and N‐[2‐(2,4,6‐trichlorophenoxy)propyl]amine (BTS40348), as single‐ and dual‐solutes, at pH 4, 7 and 9, were evaluated by use of the Freundlich isotherm model. Coal‐based activated carbon type F400 was found to most strongly adsorb both compounds, with adsorption optima at pH 4 and 9 for TCP and BTS40348, respectively. In dual‐solute isotherms, the adsorptive capacity for each solute was reduced with pH, dictating which solute was most strongly adsorbed. Compared with these batch isotherms, F400 adsorptive capacity was reduced in flow‐through column studies. Activated carbon bioregeneration was studied but the adsorptive capacity of the flow‐through column did not increase, indicating that biologically‐mediated desorption of solute did not occur.

© 2001 Society of Chemical Industry
Decomposition of H2O2 on activated carbon obtained from olive stones
Authors: Khalil Laila B , Girgis Badie S , Tawfik Tarek A M
Published: January 2005

Activated carbons were prepared from olive oil solid wastes by treatment in different schemes: impregnation with H3PO4 followed by pyrolysis at 300–700 °C, by steam pyrolysis at 600–700 °C, or by conventional steam activation at 850 °C. Porosity characteristics were determined by analysis of nitrogen adsorption isotherms, and carbons of widely different properties and surface pH values were obtained. Decomposition of H2O2 in dilute unbuffered solution was followed by measuring evolved oxygen volumetrically. First‐order kinetics was followed, and the catalytic rate coefficients were evaluated. The carbons tested showed appreciable activity where evolved oxygen attained ≈10% of the stoichiometric amount in 1 h. The degree of decomposition showed inverse dependence on surface area, pore volume and mean pore dimensions. The chemical nature of the surface, rather than the porosity characteristics, was the principal factor in enhancing the disproportionation of H2O2 on the activated carbon surface.

© 2001 Society of Chemical Industry
The effect of preparation method on the catalytic activity of amorphous aluminas in ethanol dehydration
Authors: Bakoyannakis Demetris N , Zamboulis Demetris , Stalidis George A , Deliyanni Eleni A
Published: January 2005

The known heterogeneous catalytic dehydration of ethanol on amorphous aluminium oxide samples was adopted as a measure of catalytic activity and selectivity. The aluminium oxide samples were prepared by hydrolysis of aluminium chloride using propylamine, as proton acceptor, in pure and mixed aqueous ethanolic and acetonic media, freeze dried and activated. The catalytic activity and selectivity of the samples was measured in the temperature range 623–698 K for various flow rates of ethanol. The apparent activation energies were calculated (53–78 kJ mol−1) and depended on the solvent used in the preparation of the aluminas. The effect of solvent medium on the activity and selectivity was discussed.

© 2001 Society of Chemical Industry
Extraction and recovery of gold from KAu(CN)2 using cetyltrimethylammonium bromide microemulsions
Authors: Zhang Tian‐Xi , Huang Bao‐Gui , Zhou Wei‐Jin , Gao Hong‐Cheng , Chen Jing , Wu Ha‐Shen , Wu Jin‐Guang
Published: January 2005

Extraction and stripping of KAu(CN)2 from alkaline solution by a w/o microemulsion formed with cetyltrimethylammonium bromide (CTAB) using 198Au(I) tracer has been investigated. Various parameters, such as the Au(I) concentration in aqueous phase, concentrations of halide ions, NH4SCN and thiodiethylene glycol in stripping solution as well as the relationship between water and Au(I) concentration in the organic phase in the extraction and stripping of Au(I) were studied. The results show that almost all of the Au(I) in the aqueous phase was extracted into the organic phase. The water content decreased significantly with an increase in Au(I) concentration in the organic phase, contrary to the results of a system with tributyl phosphate (TBP) as cosolvent. Almost all of the extracted Au(I) (∼98%) can be recovered with pure thiodiethylene glycol as the stripping agent, and ∼93% of the Au(I) is stripped with high concentrations of NH4SCN(>3.0 mol dm−3) or KI (>2.0 mol dm−3).

© 2001 Society of Chemical Industry
Electrochemical oxidation of tannery wastewater
Authors: Rao N N , Somasekhar K M , Kaul S N , Szpyrkowicz L
Published: January 2005

Tannery wastewater was treated by an electrochemical oxidation method using Ti/Pt, Ti/PbO2 and Ti/MnO2 anodes and a Ti cathode in a two‐electrode stirred batch reactor. The changes in colour concentration, chemical oxygen demand (COD), ammonia (NH4+), sulfide and total chromium have been determined as a function of treatment time and applied current density. Gas chromatography–mass spectrometry (GC–MS) analysis, performed on the wastewater samples before and after treatment, as well as on foam samples, is reported. Anode efficiency, rate constants and energy consumption were estimated and discussed. The efficiency of Ti/Pt was 0.802 kgCOD h−1 A−1m−2 and 0.270 kgNH4+ h−1 A−1m−2, and the energy consumption was 5.77 kWh kg−1 COD and 16.63 kWh kg−1 of NH4+. The order of efficiency of anodes was found to be Ti/Pt ≫ Ti/PbO2 > Ti/MnO2. The results indicate that the electro‐oxidation method could be used for effective oxidation of tannery wastewater and a final effluent with substantially reduced pollution load can be obtained.

© 2001 Society of Chemical Industry
Oil and fungal biomass dispersion in a stirred tank containing a simulated fermentation broth
Authors: Córdova‐Aguilar Ma Soledad , Sánchez Adriana , Serrano‐Carreón Leobardo , Galindo Enrique
Published: January 2005

The production of γ‐decalactone by the filamentous fungus Trichoderma harzianum involves four phases (oil–water–air–mycelium) and its dispersion is crucial during fermentation. Oil and biomass (when present) dispersion, as a function of the volumetric power drawn (P/V), was characterized, in two; three‐ and four‐phase systems agitated with Rushton turbines. Trichoderma harzianum mycelium was used as the solid phase in the four‐phase system. Two stages of the fermentation were simulated: the beginning (15% oil and 1.4 kgm−3 of mycelium) and the end (2% oil and 10.6 kg m−3 of mycelium). In the two‐phase system, the use of exhausted broth achieved higher oil dispersions at low P/V values as compared with distilled water. Aeration decreased the oil dispersion for the high‐oil system, but enhanced oil dispersion for the low‐oil system. Compared with the P/V used in the actual fermentation (0.2 kW m−3), a high segregation of the system was observed for the high‐oil/low‐biomass system, due to the difficulty of mixing the thick oil–air emulsion present at the top of the tank. The system simulating the end of the fermentation reached almost complete homogeneity of oil and biomass, a phenomenon due to the high biomass/oil ratio and the biomass acting as an oil carrier.

© 2001 Society of Chemical Industry
Optimisation of the biological treatment of hypersaline wastewater fromDunaliella salinacarotenogenesis
Authors: Santos Carla A , Vieira Ana M , Fernandes Helena L , Empis Jose A , Novais Júlio M
Published: January 2005

The reutilisation ofDunaliella salinacarotenogenesis medium, after microalgal biomass separation by centrifugation, was assessed. The wastewater had an NaCl concentration between 174 g dm−3and 254 g dm−3and an average total organic matter concentration of 1540 mg dm−3ash‐free dry weight, of which 41% (w/v) was glycerol. The biological treatment was established at laboratory scale and batch operations used halophilic bacteria from the wastewater itself. The wastewater was supplemented with NH4+,PO43−, K+and Mg2+ions to enhance growth. The effect of each ion addedper sewas initially investigated and a response surface methodology (RSM) used to identify the optimal conditions for maximisation of glycerol removal from the wastewater, which was considered to be the main objective. Addition of NH4+ions alone achieved 79% glycerol removal compared with only 59% in the absence of supplement, after 8 days incubation. The combined addition of ions ([NaCl] = 214 g dm−3, [Mg2+] = 114 mg dm−3, [K+] = 131 mg dm−3, [NH4+] = 113 mg dm−3, [PO43−] = 40 mg dm−3) increased glycerol removal from the wastewater such that, after 2 days incubation, no residual glycerol was apparent in cultures. These ion combinations enabled the halophilic bacteria to efficiently remove glycerol from the wastewater and consequently reduce organic matter. This treated wastewater should be appropriate for reutilisation as a carotenogenesis medium for β‐carotene production fromD salina.

© 2001 Society of Chemical Industry
Flow and mass transfer in aerated viscous Newtonian liquids in an unbaffled agitated vessel having alternating forward–reverse rotating impellers
Authors: Yoshida Masanori , Yamagiwa Kazuaki , Ito Akira , Ohkawa Akira , Abe Masahiko , Tezura Shuichi , Shimazaki Masuo
Published: January 2005

Flow and mass transfer characteristics in aerated viscous Newtonian liquids were studied for an unbaffled aerated agitated vessel with alternating rotating impellers (AAVAI), ie with multiple forward–reverse rotating impellers having four delta blades. The effects of operating conditions such as gas sparging rate, agitation rate and the number of impeller stages, and the liquid physical properties (viscosity) on the gas hold‐up, ϕgD, and volumetric oxygen transfer coefficient, kLaD were evaluated experimentally. The dependences of ϕgD and kLaD on the specific total power input and superficial gas velocity differed, depending on the ranges of liquid viscosity. Empirical relationships are presented for each viscosity range to predict ϕgD and kLaD as a function of the specific total power input, superficial gas velocity and viscosity of liquid. Based on a comparative investigation of the volumetric coefficient in terms of the specific total power input between the AAVAI and conventional aerated agitated vessels (CAAVs) having unidirectionally rotating impellers, the usefulness of AAVAI as a gas–liquid agitator treating viscous Newtonian liquids is also discussed.

© 2001 Society of Chemical Industry
Autotrophic nitrification and denitrification characteristics of an upflow biological aerated filter
Authors: Han Dong‐Woo , Yun Ho‐Joon , Kim Dong‐Jin
Published: January 2005

Wastewater nitrification was carried out using a laboratory‐scale upflow biological aerated filter (BAF) packed with a polyurethane‐based porous medium. The filtration medium has macro‐pores which provide a greater surface area for the development of biofilms. The macro‐pores have both aerobic and anaerobic zones, depending on the depth of oxygen penetration in the medium. Wastewater ammonium was oxidized at a maximum rate of 1.8 kg NH4+m−3d−1 and showed more than 90% nitrification efficiency in the BAF. During the biological nitrification of wastewater, considerable nitrogen loss was observed in the BAF under oxygen‐limited conditions when organic carbons were not provided for denitrification. Most probably, the lost nitrogen was converted to gaseous nitrogen compounds including dinitrogen by autotrophic dentrification and anaerobic ammonium oxidation.

© 2001 Society of Chemical Industry
Syntheses and biological activities of novel diheterocyclic compounds containing 1,2,4‐triazolo[1,5‐a]pyrimidine and 1,3,4‐oxadiazole
Authors: Liu Zuming , Yang Guangfu , Qin Xianghua
Published: January 2005

In a search for novel agrochemicals with high activity and low toxicity, a series of diheterocyclic compounds containing 1,2,4‐triazolo[1,5‐a]pyrimidine and 1,3,4‐oxadiazole rings were designed and synthesized by a four‐step synthetic route starting from 2‐mercapto‐5,7‐dimethyl‐1,2,4‐triazolo[1,5‐a]pyrimidine. The structures of all the compounds synthesized were confirmed by 1H NMR, mass spectroscopy and elemental analysis. The preliminary bioassay against Brassica campestris L and Echinochloa crusgalli Beavu indicated that the title compounds displayed herbicidal activity at the concentration of 100 ppm and that compounds 5a (R = CH3), 5d (R = C2H5) and 5f (R = i‐Bu) were found to have particularly high activities. In addition, the results of an in vivo test at a concentration of 50 ppm showed that all the compounds prepared were highly active against Rhizoctonia slain, but not active against Fusarium oxysporum, Gibberella zeave and Phoma sparagi. A further in vivo test showed that compound 5j possessed better fungicidal activity against Rhizoctonia solani at a concentration of 200 ppm than Carbendazim and Validamycin A, which are well known for their fungicidal activity against Rhizoctonia solani. To our knowledge, this is the first report that 1,2,4‐triazolo[1,5‐a]pyrimidine derivatives display fungicidal activity against Rhizoctonia solani.

© 2001 Society of Chemical Industry
Electrokinetic remediation of lead‐, zinc‐ and cadmium‐contaminated soil
Authors: Vengris Tomas , Binkienė Rima , Sveikauskaitė Aušra
Published: January 2005

Electrokinetic remediation of lead‐, zinc‐ and cadmium‐contaminated sand and clayey soils has been investigated under laboratory‐scale conditions. Soil extracts of heavy metals (by 1 M HCl solution) were analysed by optical emission spectrometry. The efficiency of electrochemical remediation was partially dependent on the pH of the soil media. With pH increase, the migration of heavy metal ions toward the cathode was limited. When acetic acid was added to the sandy soil, almost complete remediation was achieved. A clay layer inserted in the cathode area did enhance the remediation rate. The most effective clean‐up was achieved for zinc and cadmium, with less effective clean‐up being achieved for lead. The effectiveness of the electrokinetic remediation of heavy metal‐contaminated clayey soil was low. The appropriate acidity was not achieved using acetic acid because of the high buffering capacity of clay, and metal ion migration was impeded by its sorption onto some clay components. The conclusion was made that clays could be used as immobilizing media for heavy metal ions by electrokinetic remediation of various soils.

© 2001 Society of Chemical Industry
Partitioning behaviour of cephalexin and 7‐aminodeacetoxicephalosporanic acid in PEG/ammonium sulfate aqueous two‐phase systems
Authors: Zhu Jian‐Hang , Wei Dong‐Zhi , Cao Xue‐Jun , Liu Ye‐Qing , Yuan Zhong‐Yi
Published: January 2005

In order to develop an aqueous two‐phase system (ATPS) for cephalexin synthesis with extractive bioconversion, the partitioning behaviour of cephalexin and 7‐aminodeacetoxicephalosporanic acid (7‐ADCA) in poly(ethylene glycol) (PEG)/salt ATPS were examined. Parameters such as PEG size, salt type and tie line length were investigated to find a primary extraction system. In PEG400/ammonium sulfate and PEG400/magnesium sulfate systems, the partition coefficient of cephalexin (KC) was larger than 1 while that of 7‐ADCA (KA) deviated about 1.5. Addition of neutral salts, surfactants and water‐miscible solvents were also investigated in the primary ATPS in order to improve the separation efficiency.KCgreatly increased when neutral salts and surfactants were added to the PEG400/ammonium sulfate primary systems whereasKAwas only slightly higher than that of the additive‐free ATPS. In an improved ATPS for extractive bioconversion, consisting of PEG400 (20% w/w), ammonium sulfate (17.5% w/w), methanol (5% w/w) and NaCl (3% w/w), aKCvalue of up to 15.2 was achieved;KAwas 1.8;KP(partition coefficient of phenylglycine methyl ester) was 1.2 and the recovery yield of cephalexin was 94.2%. The results obtained from the extractive bioconversion of cephalexin in the improved ATPS showed that it is feasible to perform such an enzymatic process in an ATPS and the system offers the potential as a model for enzymatic synthesis of some water soluble products.

© 2001 Society of Chemical Industry
Prediction of functional tertiary interactions and intermolecular interfaces from primary sequence data
Authors: Pang Phillip S. , Jankowsky Eckhard , Wadley Leven M. , Pyle Anna Marie
Published: January 2005

Given the availability of sequence information for many species, one can examine how the sequence of a gene varies among different organisms. This is accomplished by aligning the sequences and observing patterns of conservation, mutation and counter‐mutation at different positions in the gene. Imbedded in these patterns is information on energetic coupling and macromolecular interactions, which can be deciphered by application of statistical algorithms. Here we report a robust approach for predicting interactions within (or between) any type of biopolymer, including proteins, RNAs and RNA‐protein complexes. Rather than maximize the number of predictions, this approach is designed to detect a limited number of highly significant interactions, thereby providing accurate results from alignments that contain a modest number of sequences (20–60). The versatility and accuracy of the algorithm is demonstrated by the successful prediction of important intramolecular interactions within RNAs, modified RNAs, and proteins, as well as the prediction of RNA‐protein and protein‐protein interactions. J. Exp. Zool. (Mol. Dev. Evol.) 304B:000000, 2005. © 2005 Wiley‐Liss, Inc.
N,N′,N″,N‴‐tetraalkylcyclam derivatives: synthesis, 99mTc‐labelling and biological properties
Authors: Jeong Jae Min , Hong Sung Hyun , Kim Young Joo , Lee Dong Soo , Chung June‐Key , Cho Jung‐Hyuck , Lee Myung Chul
Published: January 2005

We synthesized N,N′,N″,N‴‐tetraalkylcyclam derivatives in which alkyl groups were ethyl, propyl, butyl, methoxyethyl, and ethoxyethyl. We attempted to label the compounds with 99mTc. The cyclams with methyl, ethyl, and propyl could be labelled. The labelled N,N′,N″,N‴‐tetraalkylcyclam derivatives showed +1 charge. They excreted rapidly through the kidney in mice. The liver‐uptake increased slightly as the lipophilicity increased. However, the myocardial uptake was low unlikely with the +1 charged myocardial imaging agents. Copyright © 2001 John Wiley & Sons, Ltd.
Hydrogen‐deuterium exchange during the reductive deuteration of α‐ and γ‐tocopherol chromenes
Authors: Lei Huangshu , Atkinson Jeffrey
Published: January 2005

Reduction of tocopherol chromenes with heterogeneous catalysts and deuterium gas resulted in various degrees of deuterium incorporation despite the use of high purity deuterium gas. Exchange of hydrogens on C‐7 of γ‐tocopherol was evident by 2H‐NMR and could be controlled by consideration of the substrate (chromene) to catalyst ratio, concentration and temperature. Tocopherols deuterated at C3 and C4 were prepared with 94% d2 incorporation using 10% Pd/C at 0°C in ethyl acetate. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of 13C3,15N4‐labeled factor Xa inhibitor
Authors: Guilford William J. , Dallas Jerry , Arnaiz Damian
Published: January 2005

The synthesis of an isotopically‐labeled, diphenoxypyridine factor Xa inhibitor, 3‐[[6‐[3‐(4,5‐dihydro‐1‐(13C)‐methyl‐1H‐(4‐13C,15N2‐imidazol‐2‐yl)phenoxy)‐3,5‐difluoro‐4‐(4‐morpholinyl)‐2‐pyridinyl]oxy]‐4‐hydroxybenzene‐13C‐carbox‐15N‐imid‐15N‐amide, is reported for use in factor Xa binding studies using REDOR NMR. N‐benzyl protected tetralabeled N‐methylethylene diamine was an intermediate in the preparation of 3‐[4,5‐1‐(13C)‐methyl‐1H‐(4‐13C,15N2‐imidazol‐2‐yl)]phenol. Copyright © 2001 John Wiley & Sons, Ltd.
Enzyme catalysed synthesis of L‐[4‐11C]aspartate and L‐[5‐11C]glutamate
Authors: Antoni G. , Omura H. , Ikemoto M. , Moulder R. , Watanabe Y. , Långström B.
Published: January 2005

The nitriles β‐[11C]cyano‐L‐alanine 1 and γ‐[11C]cyano‐α‐amino‐L‐butyric acid 2 were obtained by enzymatic catalysis from O‐acetyl‐L‐serine and O‐acetyl‐L‐homoserine with carrier added hydrogen [11C]cyanide (0.1 µmol), using O‐acetyl‐L‐serine sulfhydrylase [EC.4.2.99.8] and O‐acetyl‐L‐homoserine sulfhydrylase [EC.4.2.99.10], respectively. L‐[4‐11C]Aspartate 3 and L‐[5‐11C]glutamate 4 were then obtained by alkaline hydrolysis of 1 and 2, respectively. Purification by semi‐preparative HPLC yielded 3 and 4 with radiochemical purities higher than 95% and with decay corrected radiochemical yields of 60–70% and 50–60%, respectively based on the total amount of collected hydrogen [11C]cyanide. The enantiomeric purities were determined, after derivatisation with N‐α‐(2,4‐dinitrophenyl‐5‐fluoro‐)‐L‐alaninamide, by HPLC to be higher than 97.5%. The total reaction times for 3 and 4, counted from end of bombardment, were 50–55 min. The specific radioactivity of 3 and 4 were approximately 30 GBq/µmol at end of synthesis starting from 20 GBq hydrogen [11C]cyanide. Copyright © 2001 John Wiley & Sons, Ltd.
Comparative evaluation of 99mTc‐ethylene bis‐l‐cysteine and 99mTc‐ethylene bis‐l‐β‐homocysteine during reversed phase HPLC analysis and electrophoresis at various pH conditions
Authors: Mang'era K.O. , Tassaert S. , Cleynhens B. , Verbruggen A. , Verbeke K.
Published: January 2005

Ethylene bis‐L‐β‐homocysteine (L,L‐EH) differs from ethylene bis‐L‐cysteine (L,L‐EC) in having an extra methylene group between each pair of amine and carboxyl groups. The objective of this study was to determine the effect of the extra methylene groups on the characteristics of the complex of these compounds with technetium‐99m during analysis by reversed phase HPLC and by electrophoresis at various pH values. Up to pH 5.5, 99mTc‐L,L‐EH exhibits a substantially longer retention time during reversed phase HPLC than 99mTc‐L,L‐EC, suggesting a more lipophilic character for 99mTc‐L,L‐EH under these conditions. On the other hand, 99mTc‐L,L‐EH clearly possesses a higher negative charge in the pH range 3‐6.5 as shown by the markedly greater migration towards the anode in electrophoresis experiments. A rational explanation for these seemingly opposing observations can not yet be offered. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of N‐protected 14C‐Labelled (2E)‐5‐amino‐5‐methylhex‐2‐enoic acid analogues
Authors: Jessen Claus U. , Selvig Helle , Valsborg Jacob S.
Published: January 2005

A novel method of preparing N‐protected (2E)‐5‐amino‐5‐methylhex‐2‐enoic acids has been developed based on the synthesis of 3‐methyl‐3‐amino‐butanol. The method was used to synthesise 14C‐labelled compounds of (1) via synthesis of triethylphosphono[1‐14C]acetate. Copyright © 2001 John Wiley & Sons, Ltd.
International Isotope Society. Abstracts of the Xth I.I.S. (UK Group) Symposium. Current themes in Isotopic chemistry.
Authors: Pringle Paul G , Olsen Henrik , Lemoucheux Laurent , Rouden Jacques , Lasne Marie‐Claire , Rayner Christopher M. , Antoni G. , Björkman M. , Kihlberg Tor , Ögren M. , Långström Bengt , Wiltshire H. R. , Buss N. , Hill Alison M. , Shipley Nick , Kingston L. P. , Lockley W. J. S. , Mather A. N. , Thompson S. P. , Wilkinson D. J. , Booth H. , Dedinas R. F. , Harding J. R. , White D. F.
Published: January 2005

The tenth annual symposium of the International Isotope Society's United Kingdom Group took place at the Alderley Park site of AstraZeneca plc. The symposium was attended by over 80 delegates from academia, the pharmaceutical and agrochemical industries, life science and fine chemical companies. Delegates were welcomed to the site by Dr Peter Warner of the Medicinal Chemistry Department.

The scientific programme consisted of presentations on isotopic chemistry and applications of labelled compounds, or of chemistry with significant implications for isotopic synthesis. Both short‐lived and long‐lived isotopes were represented, as were stable isotopes. The programme was split into a morning and afternoon session chaired by Dr John Harding (AstraZeneca, who also organised the excellent domestic programme) and Dr Karl Cable (Glaxo Wellcome). The meeting ended with concluding remarks from Dr Ken Lawrie (SmithKline Beecham), chairman of the UK Group. This years symposium had a larger attendance from other European countries, an excellent level of sponsorship was achieved, and the symposium proved self‐financing.

The next UK group symposium is planned for early October 2001.

Meeting Programme

Paul Pringle [University of Bristol, UK] To what extent can Homogeneous Catalysts be Designed?

Henrick Olsen [Novo Nordisk, Denmark] Mapping of Pharmaceutical Degradation Products in the Solid Dosage Form using Radiotracers.

Marie‐Claire Lasne [University of Caen, France] Synthesis of New Ligands of Cholinergic Receptors. Strategies for their Radiolabelling with Positron Emitters, Carbon‐11 or Fluorine‐18.

Christopher Rayner [University of Leeds, UK] Catalysis in Supercritical Carbon Dioxide ‐ What advantages does it have to Offer?

Gunnar Antoni, [University of Uppsala, Sweden] Position Specific Labelling of Biomedically Interesting Compounds using Short‐Lived Radionuclides.

Hugh Wiltshire [Hoffmann‐La Roche, UK] The Use of Stable‐Labelled Isotopes in Bioequivalence Studies with the HIV‐Protease inhibitor Saquinavir.

Alison Hill [Kings College, UK] Elucidation of Soraphen A Biosynthesis using 2H, 13C and 18O‐Labelled Precursors.

Nick Shipley [Glaxo Wellcome, UK] Preparation of P450 Substrates for use in Drug‐drug Interactions

Andrew Mather [AstraZeneca, UK] Aspects of Isotopic Labelling by Parallel Chemistry.

Helen Booth [Astra Zeneca, UK] Synthesis of 14C‐labelled forms of a series of Human Leukocyte Elastase Inhibitors.
Synthesis of tritium labeled [3R‐3H]‐, and [3S‐3H]‐L‐phenylalanine
Authors: Jemielity J. , Kanski R. , Kanska M.
Published: January 2005

The synthesis of two selectively labeled isotopomers of L‐phenylalanine, (Phe), using chemical and enzymatic methods is reported. The [3R‐3H]‐L‐Phe isotopomer has been obtained from [3‐3H]cinnamic acid prepared from benzaldehyde and malonic acid using tritiated water as a source of radioactive label, and by addition of ammonia in the presence of enzyme PAL. The [3S‐3H]‐L‐Phe isotopomer has been synthesized by addition of ammonia to cinnamic acid in a buffered medium containing PAL and tritiated water. Copyright © 2001 John Wiley & Sons, Ltd.
Simultaneous preparation of 16α‐[18F]fluoroestradiol‐sulphamates in an automated module. A high‐yield procedure for 16α‐[18F]fluoroestradiol‐17β‐sulphamate
Authors: Römer J. , Füchtner F. , Steinbach J. , Kasch H.
Published: January 2005

After successfully synthesizing 16α‐[18F]fluoroestradiol‐3,17β‐disulphamate in an automatic procedure, we studied the conditions for obtaining 16α‐[18F]fluoroestradiol‐monosulphamates in a similar manner. The described procedure can simultaneously provide approximately 3 GBq of 16α‐[18F]fluoroestradiol‐3‐sulphamate and 1 GBq of 16α‐[18F]fluoroestradiol‐17β‐sulphamate of high radiochemical purity. By treating 16α‐[18F]fluoroestradiol‐3,17β‐disulphamate with Kryptofix 2.2.2 and potassium carbonate, 16α‐[18F]fluoroestradiol‐17β‐sulphamate also becomes available at high radioactivity. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of 3H and fluorescence‐labelled poly (DL‐Lactic acid)
Authors: Ponsart S. , Coudane J. , Morgat J.‐L. , Vert M.
Published: January 2005

The novel polymer modification method based on the activation of an aliphatic polyester chain by using lithium diisopropylamide at low temperature to form a polycarbanion bearing nucleophilic sites in a position α to the carbonyl groups was applied to rac‐poly (lactic acid), PLA50, to label this polymer with radioactive tritium atoms or with a fluorescent dye. Despite simultaneous partial chain degradation, radioactive PLA50 and fluorescent PLA50 with Mn=14000 g mol−1, Mw/Mn=1.9 and Mn=32 000 g mol−1, Mw/Mn=2.4, respectively, were obtained. The specific activity of the final compound was 3.7 µCi g−1 that squared with 0.3‰ substitution reaction. The fluorescent polymer was substituted with 0.25% ratio. This work shows that the LDA activation method appears to have considerable potential. Copyright © 2001 John Wiley & Sons, Ltd.
Isotopic methylation
Authors: Bolton R.
Published: January 2005

This review reports recent methods by which organic compounds, and especially pharmaceuticals, have been isotopically labelled by the incorporation of carbon or hydrogen isotopes in methylation processes. Particular attention is paid to the incorporation of carbon‐11; both the synthesis of such labelled methylating agents and applications of their use are discussed. The review has reported reagents and conditions by which a number of organic compounds have been obtained recently. It also assesses the limitations of reported methods and proposes some alternative techniques and innovations.

The application of catalysts such as Ag+ and conditions such as microwave irradiation to encourage these reactions are also included, with suggestions of other, potentially beneficial, ways to assist them.

In many cases, the radio‐chemical yield and purity of the labelled product are given along with an estimate of the total reaction time. Copyright © 2001 John Wiley & Sons, Ltd.
[6, 7, 10, 11‐13C4]‐Labelled leukotriene B4 synthesis: standard for mass spectrometry determination and metabolic studies
Authors: Treilhou Michel , Couderc François
Published: January 2005

The mass spectrometry quantification and metabolic studies of leukotriene B4 (LTB4) in biological fluids require standards labelled with stable isotopes. This paper describes the synthesis of LTB4 labelled with 13C in positions 6, 7, 10 and 11 (1). These labelled carbons come from 13C2‐acetylene. A labelled LTB4 is obtained with an isotopic enrichment of 99%. Copyright © 2001 John Wiley & Sons, Ltd.
Carbon‐14 labeling of a trifluoromethoxy group: synthesis of a substance P antagonist
Authors: Raab Conrad E. , Dean Dennis C. , Melillo David G.
Published: January 2005

Synthesis of a carbon‐14 labeled trifluoromethoxy group has been accomplished using the stepwise oxidative fluorination–desulfurization of a readily prepared [14C]xanthate (5). This novel labeling procedure allowed a rapid synthesis of substance P antagonist candidate 1 that avoided potentially more complex ring‐labeling procedures. Similar procedures have been used to prepare C‐14 labeled trifluoromethyl and trifluoromethylamine groups. Copyright © 2001 John Wiley & Sons, Ltd.
Improved specific Synthesis of [1′‐15N]‐ and [3′‐15N]L‐histidine
Authors: Soede‐Huijbregts C. , van Laren M. , Hulsbergen F. B. , Raap J. , Lugtenburg J.
Published: January 2005

Specifically, 15N‐enriched L‐histidines have been prepared. The labelling methodology involves introduction of labels in its precursor 1‐benzyl‐5‐hydroxy methyl imidazole, which is converted into L‐histidine via the Schöllkopf method. The procedure allows the preparation of the intermediates and finally histidine with high 15N enrichment (99%) at each position, in 29% overall yield starting with 15NH4Cl and 56% with KSC15N, respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis and in vitro evaluation of iodine labelled pyrazolo[1,5‐a]pyridines as highly selective dopamine D4 receptor ligands
Authors: Prante O. , Löber S. , Hübner H. , Gmeiner P. , Kuwert T.
Published: January 2005

Two 131I‐labelled radioligands, namely 3‐(4‐[131I]iodophenylpiperazin‐1‐ylmethyl)‐pyrazolo[1,5‐a]pyridine and 3‐(4‐chlorophenylpiperazin‐1‐ylmethyl)‐7‐[131I]iodopyrazolo[1,5‐a]pyridine, which are required for studies or binding of these ligands to the D4 receptor, have been synthesized in 80% and 32% radiochemical yields, respectively; the radiochemical purity in each case was >97%. For the second radioligand a kit preparation, based on iododestannylation followed by solid‐phase extraction, was possible. In vitro characterization using CHO‐cells expressing different dopamine receptor subtypes gave Ki values of 3.1 and 2.6 nM. Both radioligands are highly selective for the D4 subtype as compared to other dopamine subtypes. Copyright © 2001 John Wiley & Sons, Ltd.
Synthesis of [11C]levofloxacin
Authors: Berridge M. S. , Burnazi E. M.
Published: January 2005

Levofloxacin, the pure S enantiomer of the fluoroquinolone antibiotic ofloxacin, was labeled via methylation of the corresponding, des‐methyl, secondary amine with N.C.A. [11C]methyl iodide. The methylation reaction was regioselective, giving predominantly the preferred methyl amine at high temperature in DMF, while otherwise giving predominantly the methyl ester of a free carboxylic acid also present in the molecule. Levofloxacin was obtained in 80% chemical yield after a 45 min synthesis. Copyright © 2001 John Wiley & Sons, Ltd.
Investigations into the regioselective deuteriation of enolates derived from silyl enol ethers and enolacetates
Authors: Coumbarides Gregory S. , Eames Jason , Weerasooriya Neluka
Published: January 2005

Results are reported on the regioselective C‐deuteriation of a series of enolates derived from the addition of MeLi to the related enolacetate and silyl enol ether and discussed in terms of the similarity between these methods; comments are made on the possible role of the additive, lithium tert‐butoxide. Copyright © 2001 John Wiley & Sons, Ltd.
Magnetic resonance imaging of in vivo kinematics after total knee arthroplasty
Authors: Lee Keh‐Yang , Slavinsky John P. , Ries Michael D. , Blumenkrantz Gabrielle , Majumdar Sharmila
Published: January 2005

Purpose

To improve the quality of magnetic resonance imaging (MRI) on knees after total knee arthroplasty (TKA) by minimizing image artifacts caused by metallic implants, and to establish a method determining in vivo kinematics of TKA knees using MRI.

Materials and Methods

Two knee implants made of cobalt‐chrome and oxidized zirconium were tested with different pulse sequences and imaging parameters. Then, in vivo kinematic MRI was performed on five well‐functioning TKAs under simulated weight‐bearing conditions. Kinematic measurements were made and a linear correlation test was run between the tibio‐ and patellofemoral measurements.

Results

The best images with minimum metallic artifacts were observed using oxidized zirconium implants, a fast spin echo sequence (FSE), thin slice thickness, and high readout gradient. TKA kinematics exhibited a large deviation from the normal kinematics and considerable patient‐to‐patient variability. However, significant linear correlations between tibiofemoral and patellofemoral kinematics were observed (R = −0.96, 0.92, 0.88).

Conclusion

Metallic artifacts due to orthopedic implants can be reduced in MR images for some materials, appropriate pulse sequence, and imaging parameters selection, enabling MR quantification of knee kinematics. Tibiofemoral kinematics appears to affect patellofemoral position after total knee arthroplasty. J. Magn. Reson. Imaging 2005;21:172–178. © 2005 Wiley‐Liss, Inc.
Indirect detection of lung perfusion using susceptibility‐based hyperpolarized gas imaging
Authors: Dimitrov Ivan E. , Insko Erik , Rizi Rahim , Leigh John S.
Published: January 2005

Purpose

To address the problem of inadequate signal‐to‐noise ratio (SNR) encountered in lung perfusion magnetic resonance imaging (MRI) by developing an indirect detection based on the strong hyperpolarized (HP) gas signal.

Materials and Methods

Our model is based on detecting the effects of gadolinium (Gd) flowing through lung capillaries by recording the phase of the nearby alveolar HP gas. In a HP gas 3He phantom we imaged gas phases before and after removing tubes containing paramagnetic solution away from the phantom. We also imaged HP gas phases in pig lungs before and after injection of Gd. Finally, parenchymal spin phase in excised lungs was measured as a function of Gd concentration.

Results

In the phantom, the differential phase map displayed a pattern characteristic of a susceptibility‐induced dipole field, showing the possibility of an indirect detection. In vivo, the differential phase map showed homogeneous appearance, as expected for uniform perfusion in healthy lungs. Ex vivo, the parenchymal spin phases were shown to depend linearly on Gd concentration.

Conclusion

Our method should allow indirect perfusion (Q) and direct ventilation (V) to be assessed simultaneously, thus allowing for diagnosis of V/Q mismatches. The linear dependency of parenchymal spin phase vs. Gd concentration may allow for quantification of lung perfusion. J. Magn. Reson. Imaging 2005;21:149–155. © 2005 Wiley‐Liss, Inc.
3.0‐Tesla MR angiography of intracranial aneurysms: Comparison of time‐of‐flight and contrast‐enhanced techniques
Authors: Gibbs Gordon F. , Huston John , Bernstein Matthew A. , Riederer Stephen J. , Brown Robert D.
Published: January 2005

Purpose

To determine whether 3.0‐T elliptical‐centric contrast‐enhanced (CE) magnetic resonance (MR) angiography is superior to 3.0‐T elliptical‐centric time‐of‐flight (TOF) MR angiography in the detection and characterization of intracranial aneurysms, and to determine whether increasing the acquisition matrix size in 3.0‐T CE MR angiography improves image quality.

Materials and Methods

A total of 50 consecutive patients referred for MR angiographic evaluation of a known or suspected intracranial aneurysm underwent MR angiography, including three‐dimensional TOF and elliptical‐centric CE techniques at 3.0 T. The 3.0‐T three‐dimensional TOF and 3.0‐T CE examinations were graded for image quality. A blind review identified the presence and location of aneurysms.

Results

A total of 28 aneurysms were identified in 23 of the 50 patients. The 3.0‐T TOF MR angiography had a higher mean score for image quality than the 3.0‐T elliptical‐centric CE MR angiography (P < 0.0001). A total of 14 patients with aneurysms had conventional angiography for comparison. The 3.0‐T TOF showed all the aneurysms, whereas 3.0‐T CE MR angiography did not show 1 of 19 aneurysms when conventional angiography was the reference standard.

Conclusion

For imaging intracranial aneurysms, 3.0‐T TOF MR angiography offers better image quality than 3.0‐T CE MR angiography using the elliptical‐centric technique. J. Magn. Reson. Imaging 2005;21:97–102. © 2005 Wiley‐Liss, Inc.