bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mass transfer‐limited wet oxidation of phenol
Authors: Tukač Vratislav , Vokál Jir̆í , Hanika Jir̆í 
Published: August 2002

AbstractCatalytic wet oxidation carried out in a continual three‐phase trickle‐bed reactor contributes to the sustainability of chemical technology. It was found that the hydrodynamics and the mass‐transfer of reactants could have a significant impact on the performance of the trickle‐bed reactor. An aqueous phenol oxidation was tested at different temperatures and liquid feed rates and the activities of both the CuO‐supported catalyst and the extruded active carbon were compared. To avoid the impact of liquid maldistribution, a bed of catalyst particles diluted with fine glass spheres was also used. Rate‐limited conditions of both liquid‐ and gas‐phase presented reactants were determined. Under the conditions of gas component transfer limitation, a better wetting of the diluted catalyst bed can lead to a worsening in the reactor performance due to the lower overall reaction rates.© 2001 Society of Chemical Industry
Utilization of response surface methodology to optimize the culture media for the production of rhamnolipids by Pseudomonas aeruginosa AT10
Authors: Abalos A , Maximo F , Manresa M A , Bastida J 
Published: August 2002

AbstractPseudomonas aeruginosa AT10 produced a mixture of surface‐active rhamnolipids when cultivated on mineral medium with waste free fatty acids as carbon source. The development of the production process to an industrial scale included the design of the culture medium. A 24 full factorial, central composite rotational design and response surface modelling method (RSM) was used to enhance rhamnolipid production by Pseudomonas aeruginosa AT10. The components that are critical for the process medium were the carbon source, the nitrogen source (NaNO3), the phosphate content (K2 HPO4/KH2PO4 2:1) and the iron content (FeSO4·7H2O). Two responses were measured, biomass and rhamnolipid production. The maximum biomass obtained was 12.06 g dm−3 DCW, when the medium contained 50 g dm−3 carbon source, 9 g dm−3 NaNO3, 7 g dm−3 phosphate and 13.7 mg dm−3 FeSO4·7H2O. The maximum concentration of rhamnolipid, 18.7 g dm−3, was attained in medium that contained 50 g dm−3 carbon source, 4.6 g dm−3 NaNO3, 1 g dm−3 phosphate and 7.4 mg dm−3 FeSO4·7H2O.© 2002 Society of Chemical Industry
Towards waste minimisation in WWTP: activated carbon from biological sludge and its application in liquid phase adsorption
Authors: Martin Maria J , Artola Adriana , Balaguer Ma Dolors , Rigola Miquel 
Published: August 2002

AbstractSurplus sludge produced during the biological treatment of wastewater requires costly disposal procedures. With increasing environmental and legislative constraints, increasing sludge production and more limited disposal options, new recycling alternatives have to be found. The possibility of obtaining activated carbons from surplus biological sludge by chemical activation with H2SO4 has been investigated. Operational parameters such as the amount of H2SO4 added, the temperature, and activation time were modified to ascertain their influence on the quality of the activated carbon obtained. The quality of the sludge‐based activated carbons was evaluated by established characterisation parameters for adsorption from solution such as phenol value, iodine number, methylene blue number and tannin value and compared with commercial activated carbons. Activation at 700 °C for 30 min in the presence of 0.5 cm3 H2SO4 g−1 dry solids in the sludge led to an activated carbon with a good capacity for iodine and tannic acid. The sludge‐derived activated carbon obtained is mesoporous in nature with a high presence of large macropores. Weak and moderate acidic surface functional groups were detected on the surface, which impart a hydrophilic nature to the solid. When compared with a commercial activated carbon, the sludge‐derived activated carbon performed better when removing dyes with a high presence of anionic solubilising groups and heavy metals. The results indicate that COD adsorption from a biologically‐treated effluent may also be an area for application.© 2002 Society of Chemical Industry
Adrenomedullin functions as an important tumor survival factor in human carcinogenesis
Authors: Cuttitta Frank , Pío Rubén , Garayoa Mercedes , Zudaire Enrique , Julián Miguel , Elsasser Ted H. , Montuenga Luis M. , Martínez Alfredo 
Published: August 2002

AbstractAdrenomedullin (AM) is a pluripotent regulatory peptide initially isolated from a human pheochromocytoma (adrenal tumor) and subsequently shown to play a critical role in cancer cell division, tumor neovascularization, and circumvention of programmed cell death, thus it is an important tumor cell survival factor underlying human carcinogenesis. A variety of neural and epithelial cancers have been shown to produce abundant amounts of AM. Recent findings have implicated elevation of serum AM with the onset of malignant expression. In addition, patients with tumors producing high levels of this peptide have a poor prognostic clinical outcome. Given that most human epithelial cancers display a microenvironment of reduced oxygen tension, it is interesting to note that AM and several of its receptors are upregulated during hypoxic insult. The existence of such a regulatory pathway has been implicated as the basis for the overexpression of AM/AM‐R in human malignancies, thereby generating a subsequent autocrine/paracrine growth advantage for the tumor cell. Furthermore, AM has been implicated as a potential immune suppressor substance, inhibiting macrophage function and acting as a newly identified negative regulator of the complement cascade, protective properties which may help cancer cells to circumvent immune surveillance. Hence, AM's traditional participation in normal physiology (cited elsewhere in this issue) can be extended to a primary player in human carcinogenesis and may have clinical relevance as a biological target for the intervention of tumor progression. Microsc. Res. Tech. 57:110–119, 2002. Published 2002 Wiley‐Liss, Inc.
Comparative ultrastructure and cytochemistry of the avian pineal organ
Authors: Fejér Zsolt , Röhlich Pál , Szél Ágoston , Dávid Csaba , Zádori Anita , João Manzano Maria , Vígh Béla 
Published: August 2002

AbstractThe breeding of birds is expected to solve problems of nourishment for the growing human population. The function of the pineal organ synchronizing sexual activity and environmental light periods is important for successful reproduction. Comparative morphology of the avian pineal completes data furnished by experiments on some frequently used laboratory animals about the functional organization of the organ. According to comparative histological data, the pineal of vertebrates is originally a double organ (the “third” and the “fourth eye”). One of them often lies extracranially, perceiving direct solar radiation, and the other, located intracranially, is supposed to measure diffuse brightness of the environment. Birds have only a single pineal, presumably originating from the intracranial pineal of lower vertebrates. Developing from the epithalamus, the avian pineal organ histologically seems not to be a simple gland (“pineal gland”) but a complex part of the brain composed of various pinealocytes and neurons that are embedded in an ependymal/glial network. In contrast to organs of “directional view” that develop large photoreceptor outer segments (retina, parietal pineal eye of reptiles) in order to decode two‐dimensional images of the environment, the “densitometer”‐like pineal organ seems to increase their photoreceptor membrane content by multiplying the number of photoreceptor perikarya and developing follicle‐like foldings of its wall during evolution (“folded retina”). Photoreceptor membranes of avian pinealocytes can be stained by antibodies against various photoreceptor‐specific compounds, among others, opsins, including pineal opsins. Photoreceptors immunoreacting with antibodies to chicken pinopsin were also found in the reptilian pineal organ. Similar to cones and rods representing the first neurons of the retina in the lateral eye, pinealocytes of birds posses an axonal effector process which terminates on the vascular surface of the organ as a neurohormonal ending, or forms ribbon‐containing synapses on pineal neurons. Serotonin is detectable immunocytochemically on the granular vesicles accumulated in neurohormonal terminals. Pinealocytic perikarya and axon terminals also bind immunocytochemically recognizable excitatory amino acids. Peripheral autonomic fibers entering the pineal organ through its meningeal cover terminate near blood vessels. Being vasomotor fibers, they presumably regulate the blood supply of the pineal tissue according to the different levels of light‐dependent pineal cell activity. Microsc. Res. Tech. 53:12–24, 2001. © 2001 Wiley‐Liss, Inc.
Enhanced resolution of membranes in cultured cells by cryoimmobilization and freeze‐substitution
Authors: Wild Peter , Schraner Elisabeth M. , Adler Hildegard , Humbel Bruno M. 
Published: August 2002

AbstractInvestigations of cellular processes demand immediate arresting of the process at any given time and excellent retention of cellular material and excellent visibility of membranes. To achieve this goal we used cryofixation to arrest cellular processes instantly and tested diverse freeze‐substitution protocols. Madin‐Darby kidney cells and Vero cells were grown on carbon‐coated sapphire disks. For cryofixation the sapphire disks covered with a cell monolayer were injected with the aid of a guillotine into liquid propane or ethane or a mixture of both cooled by liquid nitrogen. Freezing of the cryogen was prevented by using a partially insulated cylinder and by vigorous stirring that results in a substantial decrement of the freezing point of the cryogen. Cell monolayers can be cryofixed successfully using the guillotine in a safety hood at ambient temperature and humidity or at 37°C and 45% humidity. The freezing unit can also be placed in a laminar flow for working under biohazard conditions. For visualizing cell membranes at high contrast and high resolution, cells were substituted in the presence of various concentrations of glutaraldehyde and osmium tetroxide and the temperature was raised to diverse final temperatures. Substitution for 4 hours at −90°C in anhydrous acetone containing 0.25% anhydrous glutaraldehyde and 0.5% osmium tetroxide followed by a temperature rise of 5°C/hour to 0°C and final incubation for 1 hour at 0°C resulted in high contrast and excellent visibility of subcellular components at the level of the membrane bilayer. The high spatial and temporal resolution makes this methodology an excellent tool for studying cell membrane‐bound processes, such as virus‐cell interactions. Microsc. Res. Tech. 53:313–321, 2001. © 2001 Wiley‐Liss, Inc.
Effect of Helicobacter pylori eradication on cyclooxygenase 2 (COX‐2) and inducible nitric oxide synthase (iNOS) expression during gastric adaptation to aspirin (ASA) in humans
Authors: Fischer Harald , Huber Veronika , Boknik Peter , Luess Hartmut , Neumann Joachim , Schmitz Wilhelm , Domschke Wolfram , Konturek Jan W. 
Published: August 2002

AbstractGastric adaptation to aspirin is impaired in Helicobacter pylori infection, but the mechanisms underlying this phenomenon are unclear. In this study, we compared gastric mucosal expression of iNOS and COX‐2 during 14 days of aspirin ingestion in the same subjects before and 3 months after eradication of H. pylori. Compared to non‐infected controls, mucosal expression of COX‐2 and iNOS was enhanced before and 3 months after eradication of H. pylori. During aspirin ingestion, mucosal expression of COX‐2 remained unchanged before eradication of H. pylori, but increased gradually after successful antimicrobial treatment. Independent of H. pylori status, expression of iNOS increased at the beginning of aspirin intake, but then returned to initial values. We conclude that COX‐2 but not iNOS might be involved in gastric adaptation to aspirin in humans and that this mechanism appears to be impaired in H. pylori infection. Microsc. Res. Tech. 53:336–342, 2001. © 2001 Wiley‐Liss, Inc.
Seasonal changes in circulating steroid concentration and their correlation with the ovarian activity in the female Indian sheath‐tailed bat, Taphozous longimanus
Authors: Singh U.P. , Krishna A. 
Published: August 2002

AbstractThe relationship between ovarian activity and circulating steroid concentration was studied in the female sheath‐tailed bat, Taphozous longimanus. T. longimanus breeds twice in rapid succession during the year at Varanasi, India. Ovarian recrudescence was observed during September, and antral follicles were first observed during the month of October. Circulating androstenedione concentration showed an increase beginning in October, reaching a peak in December. This increase in androstenedione concentration correlated with the period of heavy accumulation of adipose tissue and increase in body mass. Antral follicles grow slowly during the period of high circulating androstenedione concentration from October to December. There was a sharp decline in androstenedione concentration during January. Simultaneously with the decline in androstenedione concentration, a sharp increase in size of the antral follicle and circulating estradiol concentration was noticed. Soon thereafter, one of the follicles ruptures, followed by fertilization and the commencement of the first pregnancy. During the second pregnancy, antral follicles first appeared during late pregnancy in March in the contralateral ovary that lacked the corpus luteum. One follicle developed rapidly and quickly attained a preovulatory stage in April. This is reflected in a sharp increase in estradiol concentration during this period. Ovulation was observed immediately following the first pregnancy in May. During this period, androstenedione concentration remained low. The results of the present study suggest that high androstenedione concentration during October to December (winter dormancy) may be responsible for slow follicular development and delays ovulation in T. longimanus. It is further hypothesized that the geographical variation in reproductive pattern of T. longimanus could be due to variation in the duration of fat storage and associated changes in the androstenedione concentration. J. Exp. Zool. 292:384–392, 2002. © 2002 Wiley‐Liss, Inc.
Role of cyclic AMP‐dependent protein kinase in oocyte maturation of the catfish, Clarias batrachus
Authors: Haider S. , Baqri S.S.R. 
Published: August 2002

AbstractThe results of the present study demonstrate the probable involvement of adenosine 3′,5′‐cyclic monophosphate (cAMP)‐dependent protein kinase (PKA) in the regulation of oocyte maturation in the catfish, Clarias batrachus. A decrease in total PKA activity with a concomitant increase in the percentage of germinal vesicle breakdown (GVBD) was found in oocytes treated with different doses of N‐(2‐[p‐bromocinnamylamino]ethyl)‐5‐isoquinoline sulfonamide (H‐89), a selective, potent inhibitor of PKA and 17α,20β‐dihydroxy‐4‐pregnen‐3‐one (17α,20β‐DP), the natural maturation‐inducing steroid of this catfish. Evaluation of time‐course of response to H‐89 and 17α,20β‐DP revealed that PKA activity decreased, and incidence of GVBD increased at all the time points when compared with their respective controls. The data further indicate that the decrease in PKA activity in H‐89‐treated oocytes was more prominent, but the induction of maturation was slower than that induced by 17α,20β‐DP. Moreover, cyanoketone (CK), an inhibitor of steroidogenesis that blocks the salmon gonadotropin (SG‐G100)‐induced GVBD, failed to abolish the maturational effect of H‐89, suggesting that H‐89 directly promotes GVBD by reducing PKA activity in oocytes. Taken together, these results indicate that inhibition of PKA activity in the oocyte of C. batrachus is directly involved in the mechanism leading to oocyte maturation. J. Exp. Zool. 292:587–593, 2002. © 2002 Wiley‐Liss, Inc.
Gonadal regeneration in masculinized female or steroid‐treated rainbow trout (Oncorhynchus mykiss)
Authors: Kersten Constance A. , Krisfalusi Michelle , Parsons James E. , Cloud J.G. 
Published: August 2002

AbstractIn salmonids, the development of an indifferent gonad into a testis or an ovary is normally determined chromosomally but can be reversed or changed by the administration of exogenous steroids during specific times in embryonic development. Because the gonads of sexually mature rainbow trout (RBT) are capable of regeneration following surgical removal and since regeneration of some tissue involves dedifferentiation, the objective of this experiment was to determine if the phenotypic sex of RBT gonads could be reversed during the regenerative process. In experiment 1, male RBT were surgically gonadectomized (Gx) or left intact and subsequently treated with estradiol‐17β, a steroid that feminizes male RBT embryos. All Gx males regenerated testicular tissue regardless of treatment. Likewise, the gonads of sham‐operated, intact fish treated with exogenous estrogen showed no evidence of sex‐reversal. In experiment 2, testes from masculinized females (XX genotype; male phenotype) were surgically removed. In all cases, only testicular tissue was regenerated in the masculinized females. Taken together, these results are consistent with the conclusion that gonads of salmonid fishes are not susceptible to sex‐reversing stimuli during the regenerative process and that gonadal regeneration in salmonids is a result of cellular proliferation of the remaining gonadal remnant. J. Exp. Zool. 290:396–401, 2001. © 2001 Wiley‐Liss, Inc.
Developmental modularity and the evolutionary diversification of arthropod limbs
Authors: Williams Terri A. , Nagy Lisa M. 
Published: August 2002

AbstractSegmentation is one of the most salient characteristics of arthropods, and differentiation of segments along the body axis is the basis of arthropod diversification. This article evaluates whether the evolution of segmentation involves the differentiation of already independent units, i.e., do segments evolve as modules? Because arthropod segmental differentiation is commonly equated with differential character of appendages, we analyze appendages by comparing similarities and differences in their development. The comparison of arthropod limbs, even between species, is a comparison of serially repeated structures. Arthropod limbs are not only reiterated along the body axis, but limbs themselves can be viewed as being composed of reiterated parts. The interpretation of such reiterated structures from an evolutionary viewpoint is far from obvious. One common view is that serial repetition is evidence of a modular organization, i.e., repeated structures with a common fundamental identity that develop semi‐autonomously and are free to diversify independently. In this article, we evaluate arthropod limbs from a developmental perspective and ask: are all arthropod limbs patterned using a similar set of mechanisms which would reflect that they all share a generic coordinate patterning system? Using Drosophila as a basis for comparison, we find that appendage primordia, positioned along the body using segmental patterning coordinates, do indeed have elements of common identity. However, we do not find evidence of a single coordinate system shared either between limbs or among limb branches. Data concerning the other diagnostic of developmental modularity—semi‐autonomy of development—are not currently available for sufficient taxa. Nonetheless, some data comparing patterns of morphogenesis provide evidence that limbs cannot always be temporally or spatially decoupled from the development of their neighbors, suggesting that segment modularity is a derived character. J. Exp. Zool. (Mol. Dev. Evol.) 291:241–257, 2001. © 2001 Wiley‐Liss, Inc.
Sex, genes, and heat: Triggers of diversity
Authors: Western Patrick S. , Sinclair Andrew H. 
Published: August 2002

AbstractIn vertebrates, sex is determined by a surprising variety of mechanisms. In many reptiles, the primary testis or ovary‐determining trigger is regulated by egg incubation temperature. This temperature dependent sex determining (TSD) mechanism occurs in all crocodilians and marine turtles examined to date and is common in terrestrial turtles and viviparous lizards (Ewert et al. 1994. J Exp Zool 270:3–15; Lang and Andrews. 1994. J Exp Biol 270:28–44; Mrosovsky. 1994. J Exp Zool 270:16–27; Pieau. 1996. Bioessays 18:19–26; Viets et al. 1994. J Exp Zool 270:45–56; Wibbels et al. 1998. J Exp Zool 281:409–416). In contrast, sex in mammals and birds is determined chromosomally (CSD). Despite these differences, morphological development of the gonads in all these vertebrate groups appears to have been conserved through evolution. Therefore, the genetic mechanisms triggering sex determination appear not to have been conserved through evolution, although the basic genetic pathway controlling the morphological differentiation of the gonads appears to have been conserved. J. Exp. Zool. 290:624–631, 2001. © 2001 Wiley‐Liss, Inc.
Receptor‐mediated delivery of an antisense gene to human brain cancer cells
Authors: Zhang Yun , Jeong Lee Hwa , Boado Ruben J. , Pardridge William M. 
Published: August 2002

AbstractBackgroundThe goal of this work was the development of a gene targeting technology that will enable the delivery of therapeutic genes to brain cancer cells in vivo following intravenous administration. High‐grade brain gliomas overexpress the epidermal growth factor receptor (EGFR) and EGFR antisense gene therapy could reduce the growth of EGFR‐dependent gliomas.MethodsA human EGFR antisense gene driven by the SV40 promoter in a non‐viral plasmid carrying elements that facilitate extra‐chromosomal replication was packaged in the interior of 85 nm pegylated immunoliposomes (PILs). The PILs were targeted to U87 human glioma cells with the 83‐14 murine monoclonal antibody (MAb) to the human insulin receptor (HIR).ResultsConfocal fluorescent microscopy demonstrated that the unconjugated HIR MAb is rapidly internalized by the glioma cells. Endocytosis followed by entry into the nucleus was also demonstrated for the HIR MAb conjugated PILs carrying fluorescein‐labeled plasmid DNA. The PILs delivered exogenous genes to virtually all cells in culture, based on β‐galactosidase histochemistry. The targeting of a luciferase gene to the U87 cells with the PILs resulted in luciferase levels in excess of 150 pg/mg protein after 72 h of incubation. The level of luciferase gene expression in the U87 cells achieved with the PIL gene targeting system was comparable to that with lipofectamine. Targeting the EGFR antisense gene to U87 glioma cells with the PILs resulted in more than 70% reduction in [3H]thymidine incorporation into the cells; this was paralleled by a 79% reduction in the level of immunoreactive EGFR.ConclusionThe present work describes the targeting of an EGFR antisense gene to human brain cancer cells, which results in a 70–80% inhibition in cancer cell growth. PILs provide a new approach to gene targeting that is effective in vivo following intravenous administration without viral vectors. Copyright © 2002 John Wiley & Sons, Ltd.