bluuebunny/crossref_metadata_2025 huggingface dataset:
Intravenous Ketoprofen in Postoperative Pain Treatment after Major Abdominal Surgery
Authors: Oberhofer Dagmar , Skok Jasna , Nesek‐Adam Visnja
Published: March 2005

In recent years considerable attention has been paid to the treatment of postoperative pain, with regard to the favorable effect of adequate analgesia on patient outcome. Multimodal analgesia (e.g., opioids and nonsteroidal anti‐inflammatory drugs [NSAIDs] or local anesthetics) is recommended for effective postoperative pain relief. There are few data on the use of NSAIDs in postoperative pain treatment after abdominal surgery. We conducted a randomized, double‐blind, placebo‐controlled study to assess the analgesic efficacy and safety of ketoprofen after major abdominal surgery. One and nine hours postoperatively patients received 100 mg of ketoprofen i.v. (n = 21) or placebo (n = 22) in addition to a pain‐treatment protocol consisting of continuous infusion of tramadol 200 mg and metamizol 5 g over 24 hours with additional 25 mg i.v. tramadol in case of inadequate analgesia. Pain was assessed by numeric rating scale at rest and at deep breath 3, 6, 12, and 24 hours postoperatively and the total dose of tramadol used in the first 24 hours was recorded. Patients in the ketoprofen group had significantly lower pain scores both at rest and at deep breath, at 3 (p < 0.01), 6, and 12 hours (p < 0.05) postoperatively. The 24‐hour use of tramadol was significantly lower in the ketoprofen group (p < 0.01), with less nausea and vomiting. There were no bleeding complications or other adverse events related to ketoprofen therapy. The study showed the value of short‐term use of ketoprofen to improve the quality of analgesia after major abdominal surgery without significant adverse effects.
The Significance of Meckel’s Diverticulum in Appendicitis — A Retrospective Analysis of 233 Cases
Authors: Ueberrueck Torsten , Meyer Lutz , Koch Andreas , Hinkel Michael , Kube Rainer , Gastinger Ingo
Published: March 2005

Conflicting reports are found in the literature concerning whether to remove an incidentally discovered Meckel’s diverticulum (MD). Between 1.1.1974 and 31.12.2000, at a single center, the perioperative data associated with appendectomy (AE) were recorded consecutively and analyzed retrospectively. All patients in whom an MD was discovered during an AE were included in the study. The clinical presentation, postoperative course, and follow‐up in all MDs left in place were analyzed. During the course of 7927 AE, 233 MD (2.9%) were detected. Of these 80.7% (n = 188) were removed and 19.3% (n = 45) were left untouched. In 9% (n = 21) of all detected diverticula pathological changes were found. Ectopic tissue was seen in 12.2% (n = 23) of the MDs removed. The postoperative complication rates did not differ significantly between patients in whom the MD was removed (9.5%; n = l8) and those in whom it was not (17.7%; n = 8); in the latter group the appendicitis was of the more acute type (gangrenous or perforated) (24.4% vs. 4.3%). In 18 patients (40.0%) with non‐removed MDs, a follow‐up period of 14.1 ± 5.8 years was achieved. Complications associated with a non‐removed MD were not observed. If during the course of an AE a MD is detected, the present data, as well as those in the literature, suggest that an individualized approach should be taken. Meckel’s diverticulum with obvious pathology should always be removed. In cases of gangrenous or perforated appendicitis, an incidentally discovered MD should be left in place, whereas in an only mildly inflamed appendix it should be removed.
Effect of Volatile Anesthetics on Oxidative Stress Due to Occupational Exposure
Authors: Türkan Hülya , Aydin Ahmet , Sayal Ahmet
Published: March 2005

Possible health hazards from long‐term exposure to inhalation anesthetics cannot yet be definitively excluded. One of the adverse effects of general anesthetics is the exogen sources of reactive oxygen radicals that are responsible for several diseases. We designed the present study to determine the effect of volatile anesthetics on oxidative stress due to occupational exposure. We enrolled 30 anesthesia and surgery personnel who had been exposed to inhalation anesthetics for 3 years and 30 healthy volunteer personnel who had not been exposed to inhalation anesthetics at any period of their life as the control group. Blood samples were taken from both groups for determination of superoxide dismutase, glutathione peroxidase, and their cofactors, which are selenium, copper, and zinc levels. Our results revealed that plasma and erythrocyte antioxidant activity and trace element levels were significantly lower in operating room personnel compared to that in the control groups. We concluded that the antioxidant defense system was affected by free radical injury in anesthesia and surgery personnel who had been exposed to inhalation anesthetics chronically. Therefore, minimizing occupational exposure to volatile anesthetics is important for protecting operation room personnel from hazards. Operating room personnel should also take antioxidant supplements.
Searching for Non‐RET Molecular Alterations in Medullary Thyroid Carcinoma: Expression Analysis by mRNA Differential Display
Authors: Musholt Thomas J. , Hanack Julia , Brehm Christoph , von Wasielewski Reinhard , Musholt Petra B.
Published: March 2005

Some 25%–70% of sporadic medullary thyroid carcinomas (MTCs) are associated with somatic mutations within the RET proto‐oncogene. In a significant number of MTCs, however, no such genetic variations can be detected, which implies alternative pathogenic molecular alterations. To assess altered RET mutation–specific gene expression, and to identify yet unknown gene transcripts involved in the tumorigenesis of MTC, we performed an expression analysis by mRNA differential display (RT‐DD). Snap‐frozen tumor tissues and corresponding normal thyroid tissues of 8 patients suffering from MTC (6 sporadic, 2 hereditary tumors) were included in the study; 5/8 MTCs harbored RET point mutations (codons 618, 634, 918). The RT‐DD method was refined by use of fluorescence‐labeled arbitrary oligonucleotides, electrophoresis on an automated sequencer, and a novel fragment‐recovery technique utilizing a high‐performance fluorescence scanner. More than 400 differentially expressed mRNA transcripts—representing upregulated or downregulated genes in the compared tissues—were detected. In all, 28 selected fragments were recovered, cloned, sequenced, and identified. Differential expression of gene transcripts with known association to cell proliferation or tumor progression—such as annexin A2, Rab11a, trefoil proteins, superoxide dismutase (SOD1), mitochondrial displacement loop (D‐loop), and G protein subunit gamma11—as well as of the neuroendocrine marker chromogranin was observed. Furthermore, several mRNA transcripts of yet unknown genes displayed mutation‐specific upregulation or downregulation in MTC. Illumination of the molecular basis especially of C‐cell carcinomas without detectable alterations of the RET receptor tyrosine kinase will be required for the development of therapeutic strategies for advanced tumors that cannot be bridled or cured by surgical interventions alone.
Differentiation in the ability to utilize Pterostyrax hispida (Ebenales: Styracaceae) among four local populations of the phytophagous ladybird beetle Henosepilachna yasutomii (Coleoptera: Coccinellidae)
Authors: Fujiyama Naoyuki , Matsumoto Kazuma , Kobayashi Norio , Ohta Yuri , Katakura Haruo
Published: March 2005

The oligophagous ladybird beetle Henosepilachna yasutomii Katakura (Coleoptera: Coccinellidae) shows inter‐population differences in its host‐use. In this beetle, populations using the deciduous tree Pterostyrax hispida Sieb. et Zucc. (Styracaceae) were recently rediscovered in the Kanto districts of central Honshu, Japan. In the present study, the ability to utilize P. hispida and other host plants was compared among four populations of H. yasutomii occurring on P. hispida and Scopolia japonica Maxim. (Solanaceae), Chelidonium japonicum Thunb. (Papaveraceae), and Solanum tuberosum L. (Solanaceae). As regards the feeding habits of adult beetles, only the populations occurring on P. hispida accepted this plant's leaves, which differed distinctly from the feeding habits of the other populations, although the differences among the four populations were not readily apparent with respect to the leaf amounts consumed. The larvae from the populations occurring on P. hispida showed significantly higher survivorship on this plant than did the larvae from the other populations. Considering the host use patterns and the life cycles of beetles under natural conditions, the large abundance of P. hispida leaves throughout the season may have played an important role in selection for the ability to utilize P. hispida observed in the H. yasutomii populations occurring on this woody host.
Dynamics of methane in mesotrophic Lake Biwa, Japan
Authors: Murase Jun , Sakai Yuji , Kametani Aya , Sugimoto Atsuko
Published: March 2005

As a part of a core project of IGBP (International Geosphere‐Biosphere Programme), distribution, production, oxidation and transport processes of methane in bottom sediments and lake water in a mesotrophic lake (Lake Biwa) have been studied with special reference to the spatial heterogeneity of each process. In this study, we attempted to synthesize previously reported results with newly obtained ones to depict the methane dynamics in the entire lake. The pelagic water column exhibited subsurface maxima of dissolved methane during a stratified period. Transect observation at the littoral zone suggested that horizontal transportation may be a reason for the high methane concentration in epilimnion and thermocline at the offshore area. Tributary rivers and littoral sediments were suggested to be the source. Observations also showed that the internal wave caused resuspension of the bottom sediment and release of methane from the sediment into the lake water. The impact of the internal waves was pronounced in the late stage of a stratified period. The littoral sediment showed much higher methanogenic activity than the profundal sediments, and the bottom water of the littoral sediments had little methanotrophic activity. In the profundal sediment, most of the methane that diffused up from the deeper part was oxidized when it passed through the oxic layer. Active methane oxidation was also observed in the hypolimnetic water, while the lake water in the epilimnion and thermocline showed very low methane oxidation, probably due to the inhibitory effect of light. These results mean a longer residence time for methane in the epilimnion than in the hypolimnion. Horizontal inflow of dissolved methane from the river and/or littoral sediment, together with the longer residence time in the surface water, may cause the subsurface maxima, which have also been observed in other lakes and in the ocean.
Seed germination of high mountain Mediterranean species: altitudinal, interpopulation and interannual variability
Authors: Giménez‐Benavides L. , Escudero A. , Pérez‐García F.
Published: March 2005

The germination response of 20 species from high altitude Mediterranean climates, most of them rare endemics, was studied. Our main goal was to model the germination response of a complete set of Iberian high mountain species. The effect of temperature and other parameters, such as spatial and temporal short gradients, on germination were also evaluated. Some seed features (mass and size) were also related to the germination response. Finally, we tested the effect of cold‐wet stratification pretreatment when germination was low under natural conditions. Seeds were collected at four locations from 1,900 to 2,400 m a.s.l. in the Sierra de Guadarrama (Spanish Central Range) over two consecutive growing seasons (2001–2002) and submitted to different temperatures and a constant photoperiod of 16 h light/8 h darkness. Most plants readily germinate without treatment, reaching an optimum at relatively high temperatures in contrast to lowland Mediterranean species. Seeds seem to be physiologically prepared for rapid germination even though these plants usually face very intense summer droughts after ripening and dispersal. Germination was also highly variable among altitudes, populations and years, but results were inconsistent among species. Such flexibility could be interpreted as an efficient survival strategy for species growing under unpredictable environments, such as the Mediterranean climate. Finally cold‐wet stratification increased germination capacity in five of nine dormant species, as widely reported for many arctic, boreal and alpine species. In conclusion, high mountain Mediterranean species do not differ from alpine species except that a relatively high number of species are ready to germinate without any treatment.
Sensitization of stefin B‐deficient thymocytes towards staurosporin‐induced apoptosis is independent of cysteine cathepsins
Authors: Kopitar-Jerala Nataša , Schweiger Ana , Myers Richard M. , Turk Vito , Turk Boris
Published: March 2005

Stefin B (cystatin B) is an inhibitor of lysosomal cysteine cathepsins and does not inhibit cathepsin D, E (aspartic) or cathepsin G (serine) proteinases. In this study, we have investigated apoptosis triggered by camptothecin, staurosporin (STS), and anti‐CD95 monoclonal antibody in the thymocytes from the stefin B‐deficient mice and wild‐type mice. We have observed increased sensibility to STS‐induced apoptosis in the thymocytes of stefin B‐deficient mice. Pretreatment of cells with pan‐caspase inhibitor z‐Val‐Ala‐Asp(OMe)‐fluoromethylketone completely inhibited phosphatidylserine externalization and caspase activation, while treatment with inhibitor of calpains‐ and papain‐like cathepsins (2S,3S)‐trans‐epoxysuccinyl‐leucylamido‐3‐methyl‐butane ethyl ester did not prevent caspase activation nor phosphatidylserine exposure. We conclude that sensitization to apoptosis induced by STS in thymocytes of stefin B‐deficient and wild‐type mice is not dependent on cathepsin inhibition by stefin B.
Effect of Permeate Flux Rate on Alkaloid Production in a Novel Plant Cell Membrane Reactor Using Coffea arabica Cells
Authors: Lang Jeffrey A. , Yoon Kwang‐Hun , Prenosil Jiri E.
Published: March 2005

A novel membrane reactor was developed for phytochemical production using plant cells. The membrane reactor was a flat plate construction. An autoclavable, polypropylene membrane sheet with pore size 0.075 μm. was used. The membrane was surfactant treated by the manufacturer. Medium was recirculated through medium channels under the membrane. Cells were supplied with nutrients by permeated medium and obtained oxygen from the surrounding gas phase. In this work, the effect of permeate flux rate on cell growth, glucose uptake, and alkaloid production was examined. An arbitrary pressure index scale was developed to regulate the amount of medium that permeated the membrane. It was based on differential pressures between the cell chamber and the medium recirculation loop. These pressures were measured at the medium inflow and outflow points to the membrane reactor. Three 21‐day batch runs were carried out with the membrane reactor at pressure indices 38, 53, and 68 and compared to parallel shake‐flask runs. The pressure index 53 run was determined to be optimum for cell growth and purine alkaloid formation. Cell mass increase in the membrane reactor was 3.2‐fold and in parallel suspension cultures was 3.3‐fold, approximately 1.5 times that of the other two reactor runs. Glucose decreased linearly in the pressure index 53 membrane reactor run to 7.7 g/L, while glucose was completely consumed in the suspension cultures after 12 days. Final alkaloid concentration was 46.1 mg/L for the pressure index 53 membrane reactor run, approximately 2 times that of the other two membrane reactor runs and the suspension cultures.
Modification of Enzyme Activity in Reversed Micelles through Clathrate Hydrate Formation
Authors: Rao A. Madhusudhan , Nguyen Huyen , Johnn Vijay T.
Published: March 2005

The physical phenomenon of clathrate hydrate formation in protein‐containing reversed micelles is described. Hydrate formation in reversed micelles is a method of adjusting the water to surfactant molar ratio, wo, which influences micellar size. Lipase and α‐chymotrypsin encapsulated in large reversed micelles of high wo show significant enhancements in activity when the micelle size is reduced through hydrate formation. Alternate methods of micelle size adjustments also show enhancements in activity. The implications for improving the activity of such encapsulated enzymes recovered from fermentation media through phase transfer into reversed micelles are discussed.
Expression of Three Recombinant Proteins Using Baculovirus Vectors in 23 Insect Cell Lines
Authors: Hink W. F. , Thomsen D. R. , Davidson D. J. , Meyer A. L. , Castellino F. J.
Published: March 2005

Recombinant Autographa California baculoviruses expressing genes for pseudorabies virus glycoprotein (gp50T), human plasminogen (HPg), and β‐galactosidase (β‐gal) were used to infect 23 cell lines or strains. The objectives were to compare amounts of recombinant proteins expressed in the cell lines, compare yields from clones and parent lines, investigate the effects of long‐term culture in serum‐free medium on production, and determine if some lines yield gp50T with different glycosylation patterns. For HPg, IZD‐MB0503 had the highest yield and four other lines (IPLB‐TN‐R2, IPLBSF‐1254, IPLB‐LdEIta, and CM‐1) had levels above that of SF‐9 cells. For gp50T, four lines (IPLB‐HvT1, IPLB‐SF21AE, IPLB‐SF21AE‐15, and IPLB‐SF‐1254) had higher amounts than SF‐9 cells. Some lines yielded gp50T with molecular mass about 1000 daltons larger than that from SF‐9 cells, which suggests increased oligosaccharide processing. Equally high levels of β‐gal were expressed in three lines (SF‐9, IZD‐MB0503, and BCIRL‐PX2‐HNV3). The major conclusion is that no single cell line produced highest yields for all three recombinant proteins. Four lines were cultured in serumfree medium for 31–34 passages and then infected with the three recombinant viruses. For most cell line‐recombinant combinations, the yields in serum‐free medium were equal to or better than those in serum‐supplemented medium. Medium composition had a much stronger effect on foreign gene expression than on susceptibility of cells to wild‐type virus.
Strategies for the Recovery of Chemicals from Fermentation: A Review of the Use of Polymeric Adsorbents
Authors: Garcia Antonio A.
Published: March 2005

Many different compounds can be produced by using microorganisms or enzymes. An important element in the design of a viable biotechnological process is the selection of an economical and efficient separations train. Production of chemicals via biotechnology generally requires isolation and purification from dilute, aqueous solution. A general framework for separation process design relies on exploiting a unique molecular physicochemical property (or properties) for separating the molecule of interest from water and the other species in solution. Important properties that can be utilized for the recovery of low molecular weight polar compounds are molecular charge, hydrophobicity, Lewis acidity or basicity, volatility, and limited solubility. In turn, it can be useful to characterize molecular properties by using separation processes, such as, for example, hydrophobicity by measuring octanol/water partition coefficients. This paper reviews the use of adsorption onto hydrophobic, nonpolar macroreticular polymers and Lewis acid‐base complexation by using functionalized polymers for the recovery of amino acids, carboxylic acids, alcohols, and ketones from dilute aqueous solution. The focus will be on utilizing physical and chemical properties to predict uptake capacity. This information will be relevant to separation process development and will help to characterize molecular properties in aqueous solution.
Application of Population Balance Model to the Loss of Hybridoma Antibody Productivity
Authors: Lee Gyun Min , Varma Amit , Palsson Bernhard O.
Published: March 2005

A simple dynamic model has been applied to explain the population dynamics of monoclonal antibody (MAb) producing (producer) and nonproducing hybridoma cells (nonproducer) coexisting in culture. The events of mutation or loss of genes associated with antibody synthesis have been incorporated into the model to account for the conversion of a producer to a nonproducer. The model shows that the cell population is not necessarily dominated by the nonproducer, and a steady balance of producer and nonproducer populations can be achieved. A nonproducer population is undesirable, and cultivation strategies to maximize MAb production are suggested, taking into account the dynamics of a nonproducer population.
Acetone‐Butanol‐Ethanol (ABE) Fermentation and Simultaneous Separation in a Trickle Bed Reactor
Authors: Park Chang‐Ho , Okos Martin R. , Wankat Phillip C.
Published: March 2005

A new in situ product separation technique using gas stripping was applied to acetone‐butanol‐ethanol (ABE) fermentation in a gas‐phase‐continuous immobilized cell trickle bed reactor. Both numerical and experimental studies showed that glucose conversion could be improved when the inhibitory compounds were stripped by fermentation gas. Solvents were stripped preferentially from the fermentation broth, and butanol removal was as efficient as acetone removal in spite of butanol's high boiling point (117°C) because of butanol's high volatility at fermentation concentrations. Since most of the butanol was removed by gas stripping, organic acids played major roles among inhibitory products. Numerical analysis indicated that improvement of glucose conversion by gas stripping was more pronounced at higher gas flow rates, with stronger inhibition kinetics, and under vacuum conditions. Numerical calculation predicted that glucose concentrations higher than 60 g/L could be converted, but this could not be shown experimentally because of increased degeneration.
Metabolic Regulation of End Product Distribution in Lactobacilli: Causes and Consequences
Authors: Tseng Ching‐Ping , Montville Thomas J.
Published: March 2005

This review examines the regulation of end product distribution in Lactobacillus plantarum and other lactobacilli, the factors that influence this distribution, and the bioenergetic consequences of end product distribution. Similarities to and differences from other genera in the lactic acid bacteria are described. Lactobacilli use many different transport systems to obtain nutrients. Carbohydrates and organic acids are transported in cells by specific phosphoenolpyruvate phosphotransferases (PEP—PTS) or permeases. The carbohydrates are then metabolized to different end products through a common key intermediate, pyruvate. The ability of lactobacilli to produce various end products depends on species, strains, genetic capacity, expression of enzyme activity, sugar structure, and environmental conditions. The regeneration of the NAD+ required for continued glycolysis is a key regulatory factor of end product distribution. The excretion of protons with acidic end products can directly generate a proton motive force and it also contributes to intracellular pH homeostasis. Anionic precursor—product exchange systems can also generate a proton motive force if the exchange is not electroneutral.
Characterization of Gene Expression in Recombinant Escherichia coli Cells Infected with Phage λ
Authors: Miao Fudu , Drake Steven K. , Kompala Dhinakar S.
Published: March 2005

Phage λ infection was investigated for possible production of toxic foreign proteins in Escherichia coli. The target gene transcription was regulated by a T7 promoter, which was initiated under the action of T7 RNA polymerase delivered by infecting phage. Two types of phage infection were investigated. In both cases, deletion of the int gene prevents lysogenic integration. One phage, λCE6, contains the Sam7 lysis mutation, so that infectious phage particles remain intracellular. The other phage, λCE6M, undergoes the complete lytic pathway so that the infected cell is eventually lysed. The dynamics of phage adsorption, foreign protein synthesis, and cell growth were analyzed as a function of various parameters, such as MOI (multiplicity of infection), cell concentration at infection, culture temperature, and different carbon sources. A low basal level of the foreign protein, β‐galactosidase, was obtained prior to infection, whereas it reached about 0.1 g/L after phage “induction” under appropriate infection conditions. Due to low basal expression, this expression system is useful for the production of toxic foreign proteins.
Large‐Scale Production of κ‐Carrageenan Droplets for Gel‐Bead Production: Theoretical and Practical Limitations of Size and Production Rate
Authors: Hunik Jan H. , Tramper Johannes
Published: March 2005

Immobilization of biocatalysts in κ‐carrageenan gel beads is a widely used technique nowadays. Several methods are used to produce the gel beads. The gel‐bead production rate is usually sufficient to make the relatively small quantities needed for bench‐scale experiments. The droplet diameter can, within limits, be adjusted to the desired size, but it is difficult to predict because of the non‐Newtonian fluid behavior of the κ‐carrageenan solution. Here we present the further scale‐up of the extrusion technique with the theory to predict the droplet diameters for non‐Newtonian fluids. The emphasis is on the droplet formation, which is the rate‐limiting step in this extrusion technique. Uniform droplets were formed by breaking up a capillary jet with a sinusoidal signal of a vibration exciter. At the maximum production rate of 27.6 dm3/h, uniform droplets with a diameter of (2.1 ± 0.12) × 10−3 m were obtained. This maximum flow rate was limited by the power transfer of the vibration exciter to the liquid flow. It was possible to get a good prediction of the droplet diameter by estimating the local viscosity from shear‐rate calculations and an experimental relation between the shear rate and viscosity. In this way the theory of Newtonian fluids could be used for the non‐Newtonian κ‐carrageenan solution. The calculated optimal break‐up frequencies and droplet sizes were in good agreement with those found in the experiments.
Ion Exchange of Lysozyme during Permeation across a Microporous Sulfopropyl‐Group‐Containing Hollow Fiber
Authors: Shinano Hironori , Tsuneda Satoshi , Saito Kyoichi , Furusaki Shintaro , Sugo Takanobu
Published: March 2005

A microporous hollow fiber containing a sulfopropyl (SP) group as a strongly acidic cation‐exchange group was prepared by radiation‐induced graft polymerization of glycidyl methacrylate, followed by hydrolysis of the resulting epoxide group into a diol, and then conversion of the diol into the SP group. The SP group density of the resulting hollow fiber ranged from 0.21 to 0.84 mol/kg of dry fiber with a pure water flux of 2.7 m/h at a filtration pressure of 0.1 MPa. Lysozyme adsorption was examined during permeation of the lysozyme solution (pH 6) through the pores across a microporous cation‐exchange hollow fiber. The lysozyme concentration of the effluent penetrating the outside of the hollow fiber did not change irrespective of the residence time of the solution across the hollow fiber, which was indicative of the negligible diffusional resistance of lysozyme to the SP group. The binding capacity of lysozyme to the fiber was constant in this range of SP group density. For comparison, the adsorption characteristics of a cupric chloride solution during permeation were also determined. The binding capacity of Cu to the fiber increased linearly with increasing SP group density, because cupric ions of a smaller size than lysozyme can invade the depths of the grafted polymer branches formed in the amorphous domain of the polymer matrix.
Affinity‐Based Reverse Micellar Extraction and Separation (ARMES): A Facile Technique for the Purification of Peroxidase from Soybean Hulls
Authors: Paradkar Vikram M. , Dordick Jonathan S.
Published: March 2005

A new technique for the purification of proteins has been developed which combines the high selectivity of affinity interaction with the scalability and ease of operation of liquid‐liquid extraction. The approach is called affinity‐based reverse micellar extraction and separation (ARMES). The salient features of ARMES include the following: (1) intraphasic interaction between the ligand and ligate which provides for high ligand utilization; (2) no chemical modification of the ligand is needed; and (3) ease of operation and inherent scalability due to the use of liquid‐liquid extraction. This technique has been used to purify the peroxidase from soybean hulls using the lectin concanavalin A (con A) as a sugar‐binding affinity ligand. A purification factor of 30 is achieved to provide a nearly pure peroxidase solution (as determined by HPLC and SDS‐PAGE) with nearly complete regeneration of the con A ligand. We propose that ARMES will be useful in the facile purification of complex biomolecules such as glycoform protein variants using lectins as affinity ligands and proteins of therapeutic importance using antibodies as affinity ligands.
Expansion and Differentiation of Human Hematopoietic Cells from Static Cultures through Small‐Scale Bioreactors
Authors: Sardonini Charles A. , Wu Ying‐Jye
Published: March 2005

Maintenance of the progenitor cells responsible for hematopoiesis has generally been accomplished using a feeder layer of stromal cells in stationary culture. Here, we compared the expansion of the total cell and progenitor cell populations using low‐density mononuclear cells (LDMCs) obtained from human bone marrow in static culture (T‐flasks) and in different cell culture bioreactors designed for the scale‐up of mammalian cells. Static cultures were performed without the presence of a previously established stromal cell layer. Expansion of marrow in all cases was accomplished through the use of added cytokines such as IL‐3, GM‐CSF, and c‐kit ligand. The results for the total cell expansion in static culture ranged from 4.4‐ to 32‐fold. The cell number increase was affected by such factors as patient to patient variability, freeze‐thawing, and the combination of cytokines used. Due to widespread use and the small amount of marrow needed, static cultures were used as a basis for comparison with other expansion systems. The cell culture systems used to evaluate the scale‐up of marrow cultures included suspension, microcarrier, airlift, and hollow fiber bioreactors. Using identical media, cytokines, and feed schedules, LDMCs in the suspension bioreactor expanded to a value of 1.6 compared to a normalized value of 1.0 for static cultures for the two runs investigated. Expansion results for microcarrier cultures averaged 0.75 when compared to static cultures. A cell number increase in the airlift bioreactor resulted in an expansion which was 0.70 of the control static culture. Granulocyte—macrophage and erythroid progenitor assay data were also evaluated for the suspension, microcarrier, and airlift bioreactors. A single run for the hollow fiber system demonstrated no observable expansion of hematopoietic cells when compared to control static cultures. However, this finding may be a reflection of the inefficiency in retrieving cells from the extracapillary space of the hollow fiber bioreactor. Although the expansion results observed here are of limited clinical utility, these studies provide a basis for future development for the scale‐up of hematopoietic cultures.
Colloidal Properties of Flocculent and Nonflocculent Brewing Yeast Suspensions
Authors: Speers R. Alex , Durance Timothy D. , Tung Marvin A. , Tou Janet
Published: March 2005

The orthokinetic flocculation rates of four suspensions of Saccharomyces cerevisiae and Saccharomyces uvarum (calsbergensis) were measured using steady shear rheometry and light microscopy. These results, along with cell ζ potential values previously reported by the authors, allowed us to test the applicability of DLVO (Derjaguin, Landau, Verwey, and Overbeek) mediated orthokinetic flocculation models. The findings also permitted examination of the validity of the elastic floe model and allowed estimation of the force required to separate cell doublets. Cellular suspensions of brewing yeast were subjected to a high shear treatment to reduce any floes to single cells. Periodic samples were then taken while shearing the suspension at 200 s−1, and the extent of flocculation was determined via light microscopy. The logarithm of floe concentration was linearly dependent on shearing time. It was possible to estimate orthokinetic capture coefficients (αo) for the four strains, with values ranging from 0.00025 to 0.0010. By using measured and “typical” colloidal parameters, a theoretical αo value was derived which was much lower than the experimental values (i. e., αot ≪ 0.0001). Thus, it was concluded that the DLVO flocculation model could not be used to explain brewing yeast flocculation. Flow behavior of the yeast suspensions followed the Bingham model above a critical shear rate. Values of this critical shear rate (which predicts the point at which cell doublets separate) were used to calculate the force required to separate doublet cells. A calculated force of 2.2 × 10−11 N was similar to that of lectin‐like bonds that are believed to be involved in yeast flocculation. As well, the elastic floe model could be employed to predict Bingham yield stress values.
Molecular Cloning of the γ‐Glutamyltranspeptidase Gene from a Pseudomonas Strain
Authors: Ishiye Masayuki , Yamashita Mitsuo , Niwa Mineo
Published: March 2005

γ‐Glutamyltranspeptidase (GGT) was purified from a Pseudomonas sp. strain A14. The purified enzyme was found to be composed of two nonidentical subunits with molecular weights of 39000 and 22000 and had a pI of >8.6. The partial N‐terminal amino acid sequences of both subunits and some proteolytic fragments were determined. Using mixed oligonucleotides designed from the partial amino acid sequences as hybridization probes, one cosmid clone which contained the GGT gene was isolated from a Pseudomonas sp. strain A14 cosmid genome library, and the DNA sequence of the GGT gene was determined. The nucleotide sequence and the protein sequence analysis revealed that GGT was synthesized as a precursor protein of 575 amino acids and then processed to mature enzyme, presumably after removal of a signal peptide. Comparison of the predicted amino acid sequence of Pseudomonas GGT with published results for Escherichia coli K‐12 and rat kidney GGTs shows that the protein sequence of Pseudomonas GGT is 51% and 33% identical to the E. coli and rat GGT sequences, respectively. Higher similarity is observed among the small subunits, which have been thought to have a binding site for the γ‐glutamyl residue. Expression of the cloned Pseudomonas GGT gene in E. coli was subjected to Western blot analysis using antibody raised against the purified GGT. This suggested that processing of the precursor protein to its subunits is temperature‐dependent, because the amount of mature GGT protein was increased when the culture was performed at low temperature.
Sub‐Micrometer‐Sized Biodegradable Particles of Poly(L‐Lactic Acid) via the Gas Antisolvent Spray Precipitation Process
Authors: Randolph Theodore W. , Randolph Alan D. , Mebes Michael , Yeung Sharon
Published: March 2005

Sub‐micrometer‐sized particles of poly(L‐lactic acid) may be formed by using nearcritical or supercritical carbon dioxide as an antisolvent to precipitate poly(L‐lactic acid) from droplets of methylene chloride solution sprayed into a carbon dioxide continuous phase. Particle sizes may be controlled by varying the density of the carbon dioxide; at constant temperature in the supercritical region, higher carbon dioxide densities yield larger particles. Two methods (one batch and one continuous) for introducing the poly(L‐lactic acid) solutions into carbon dioxide are demonstrated. Although the two methods use very different mechanisms for forming the droplets, similar particle sizes are observed as a function of carbon dioxide density. We suggest that mass transport, rather than jet breakup and hydrodynamics, controls particle sizes in the near‐critical and supercritical regions.
Effect of Preinduction Specific Growth Rate on Secretion of Granulocyte Macrophage Colony Stimulating Factor by Escherichia coli
Authors: Curless Craig E. , Pope Joe , Loredo Lawrence , Tsai Larry B.
Published: March 2005

The effect of preinduction specific growth rate on the rate of synthesis and processing of granulocyte macrophage colony stimulating factor (GMCSF) secreted by Escherichia coli was investigated. A chemostat was used to explore preinduction growth rates ranging from 0.038 to 0.2/h. The maximum yields of both total GMCSF and processed GMCSF were found to occur at a preinduction growth rate of 0.13h. It was also discovered that if the postinduction feed rate is reduced at a preinduction growth rate near 0.13h, then the same amount of processed GMCSF is formed, but no unprocessed GMCSF is produced. It was hypothesized that the rate of synthesis of total GMCSF increases with an increased preinduction specific growth rate, but translocation across the cytoplasmic membrane and processing is rate‐limiting. Increased degradation of GMCSF during induction at higher preinduction specific growth rates decreased the amount of GMCSF produced.
The origin of Intermediate and Subpolar Mode Waters crossing the Atlantic equator in OCCAM
Authors: Drijfhout S. S. , Donners J. , de Ruijter W. P. M.
Published: March 2005

The origin of the intermediate waters that cross the equatorial Atlantic as part of the return flow for North Atlantic Deep Water was studied in a high resolution global ocean model using a Lagrangian particle following technique. Most of these waters are subducted in the southeast Indian Ocean. Less than twenty percent comes directly from Drake Passage without looping into the Indian Ocean; the majority being provided by Agulhas leakage. Most of the intermediate waters that subduct in the South Atlantic do not follow the South Atlantic/Indian Ocean supergyre, but remain within the Antarctic Circumpolar Current, and gradually transform into Circumpolar Deep Water by diapycnal mixing.
Analysis of 40 years of solar radiation data from China, 1961–2000
Authors: Che H. Z. , Shi G. Y. , Zhang X. Y. , Arimoto R. , Zhao J. Q. , Xu L. , Wang B. , Chen Z. H.
Published: March 2005

Trends in Chinese global radiation, direct horizontal radiation, diffuse radiation, clearness index, diffuse fraction and percentage of possible sunshine duration for the period 1961–2000 were evaluated based on data for daily surface solar radiation and monthly sunshine duration. Annual means for all six variables were calculated for each station and for China as a whole. Linear regression analysis was used to characterize long‐term annual trends in these variables. Over the latter half of the 20th century, there have been significant decreases in global radiation (−4.5 W/m2 per decade), direct radiation (−6.6 W/m2 per decade), clearness index (−1.1% per decade), and the percentage of possible sunshine duration (−1.28% per decade), but diffuse fraction has increased (1.73% per decade). Although there is some evidence that conditions have improved in the last decade, the consistent spatial and temporal variations of these variables support the theory that increased aerosol loadings were at least partially responsible for the observed decreases in global radiation and direct radiation, the clearness index, and the monthly percentage of possible sunshine duration over much of China.
Mining airborne particulate size distribution data by positive matrix factorization
Authors: Zhou Liming , Kim Eugene , Hopke Philip K. , Stanier Charles , Pandis Spyros N.
Published: March 2005

Airborne particulate size distribution data acquired in Pittsburgh from July 2001 to June 2002 were analyzed as a bilinear receptor model solved by positive matrix factorization (PMF). The data were obtained from two scanning mobility particle spectrometers and an aerodynamic particle sampler with a temporal resolution of 15 min. Each sample contained 165 size bins from 0.003 to 2.5 μm. Particle growth periods in nucleation events were identified, and the data in these intervals were excluded from this study so that the size distribution profiles associated with the factors could be regarded as sufficiently constant to satisfy the assumptions of the receptor model. The values for each set of five consecutive size bins were averaged to produce 33 new size intervals. Analyses were made on monthly data sets to ensure that the changes in the size distributions from the source to the receptor site could be regarded as constant. The factors from PMF could be assigned to particle sources by examination of the number size distributions associated with the factors, the time frequency properties of the contribution of each source (Fourier analysis of source contribution values), and the correlations of the contribution values with simultaneous gas phase measurements (O3, NO, NO2, SO2, CO) and particle composition data (sulfate, nitrate, organic carbon/elemental carbon). Seasonal trends and weekday/weekend effects were investigated. Conditional probability function analyses were performed for each source to ascertain the likely directions in which the sources were located. Five factors were separated. Two factors, local traffic and nucleation, are clear sources, but each of the other factors appears to be a mixture of several sources that cannot be further separated.
Microcapillary plate as a built-in intensifier for semiconductor gas discharge image converters
Authors: Portsel L. M. , Marchenko V. M. , Purwins H.-G.
Published: March 2005

Using a microcapillary discharge plate (MCDP) integrated with the discharge gap of a semiconductor gas discharge infrared image converter has been tested as a basis for building gas discharge image converters with internal image intensification. A Townsend-type discharge with current density controlled by infrared illumination of the semiconductor cathode is produced in a 100 μm gap in Ar gas under pressures of 50 – 200 hPa. Electrons generated in the discharge gap are multiplied by a non-self-sustained discharge in the MCDP of 100 μm thickness, which has just a single channel 200 μm in diameter. The authors have observed a significant increase of the discharge brightness in the MCDP channel compared to that of the main discharge gap.
Multiconfiguration perturbation theory: Size consistency at second order
Authors: Szabados Ágnes , Rolik Zoltán , Tóth Gábor , Surján Péter R.
Published: March 2005

A modified version of a previously elaborated multiconfiguration perturbation theory (MCPT) [Rolik et al. J. Chem. Phys. 119, 1922 (2003)] is presented. In the modified formulation size consistency is ensured at second order in energy, by omitting projectors from the zero order Hamiltonian operator. This MCPT formulation is abbreviated as SC2-MCPT (size consistent at second order). To ensure proper separability, we also require that energy denominators are constructed as differences of some one-particle energies. A similar choice for energy denominators also renders the well-known multireference Møller–Plesset (MRMP) energy size consistent at second order. The same thing applies to the related multireference perturbation theory by Witek, Nakano, and Hirao.
Geometric, electronic, and bonding properties of AuNM (N=1–7, M=Ni, Pd, Pt) clusters
Authors: Yuan D. W. , Wang Yang , Zeng Zhi
Published: March 2005

Employing first-principles methods, based on density functional theory, we report the ground state geometric and electronic structures of gold clusters doped with platinum group atoms, AuNM (N=1–7, M=Ni, Pd, Pt). The stability and electronic properties of Ni-doped gold clusters are similar to that of pure gold clusters with an enhancement of bond strength. Due to the strong d-d or s-d interplay between impurities and gold atoms originating in the relativistic effects and unique properties of dopant delocalized s-electrons in Pd- and Pt-doped gold clusters, the dopant atoms markedly change the geometric and electronic properties of gold clusters, and stronger bond energies are found in Pt-doped clusters. The Mulliken populations analysis of impurities and detailed decompositions of bond energies as well as a variety of density of states of the most stable dopant gold clusters are given to understand the different effects of individual dopant atom on bonding and electronic properties of dopant gold clusters. From the electronic properties of dopant gold clusters, the different chemical reactivity toward O2, CO, or NO molecule is predicted in transition metal-doped gold clusters compared to pure gold clusters.
Second-harmonic generation optical activity of a polypeptide α-helix at the air∕water interface
Authors: Mitchell S. A. , McAloney R. A. , Moffatt D. , Mora-Diez N. , Zgierski M. Z.
Published: March 2005

Quantitative measurements of second-harmonic generation optical activity (SHG-OA) have been performed for α-helical polypeptides poly-(γ-benzyl-L-glutamate) and poly-(γ-ethyl-L-glutamate) adsorbed at the air∕water interface, with the fundamental frequency ℏω=2.96eV (λ=417nm). The chiral component of the nonlinear susceptibility χXYZ(2) is small for both polymers, being comparable in magnitude with the susceptibility χXXZ(2) of the clean air∕water interface. The microscopic origin of the nonlinear response has been investigated by using semiempirical ZINDO∕S calculations in conjunction with standard time-dependent perturbation theory to evaluate the molecular hyperpolarizability tensor of a model α-helix composed of glycine residues. Calculated nonlinear susceptibilities (per monomer unit) are in good agreement with experimental measurements for both the chiral and achiral response. The computational results indicate that charge transfer transitions of the α-helix have a large influence on the achiral components of the hyperpolarizability tensor, and produce characteristic features in the response under suitable experimental conditions. The dominant origin of SHG-OA for the model α-helix is a structural effect due to the tilt of the plane of each amide group of the helix relative to the helical axis. SHG-OA is associated with the orientational distribution of isolated, achiral chromophores, and is present in the absence of electronic coupling between the amide subunits of the polypeptide α-helix.
On quadratic Poisson brackets
Authors: Kisisel Ali Ulas Özgür
Published: March 2005

In this paper, we present a method for constructing large families of quadratic Poisson brackets on a manifold using more elementary brackets on a different manifold. The method is then applied to several examples of completely integrable systems. One can recover several known brackets for systems such as the Toda lattice or the open discrete KP hierarchy. New brackets for a doubly periodic discrete KP hierarchy are also constructed.