bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative analysis of axon collaterals of single neurons in layer IIa of the piriform cortex of the guinea pig
Authors: Yang Junli , Ul Quraish Afraz , Murakami Kunio , Ishikawa Youichi , Takayanagi Masaaki , Kakuta Sachiko , Kishi Kiyoshi
Published: March 2004

To study the various types of neurons in layer IIa in the piriform cortex (PC) and the spatial distribution of their axons, axon collaterals of three neurons in layer IIa were labeled and quantitatively analyzed by intracellular injection of biocytin in the guinea pig. Individual neurons have highly distributed axon collaterals, which display a little tendency toward patchy concentrations inside as well as outside the PC. One semilunar cell in the posterior PC had 54‐mm‐long axon collaterals and 4,200 boutons, out of which 2,100 (49% of the total number of boutons) were distributed in the PC. One semilunar‐pyramidal transitional cell in the posterior PC had 256‐mm‐long axon collaterals and 23,000 boutons, out of which 16,100 (70% of the total number of boutons) and 4,000 (18% of the total number of boutons) were respectively distributed in all layers and in layer Ia of the PC. One multipolar cell in the posterior PC had 188‐mm‐long axon collaterals and 18,000 boutons, out of which 13,700 (78% of the total number of boutons) were distributed in the PC. Our results revealed that the connection patterns of individual cells in layer IIa have most of the features required for an associative neural network, which may function as a content‐addressable memory for the association of odor stimuli. J. Comp. Neurol. 473:30–42, 2004. © 2004 Wiley‐Liss, Inc.
Pyrazolate‐Based Dinucleating Ligands in L2M2 Scaffolds: Effects of Bulky Substituents and Coligands on Structures and M···H−C Interactions
Authors: Röder Jens C. , Meyer Franc , Kaifer Elisabeth , Pritzkow Hans
Published: March 2004

A series of nickel(II) and palladium(II) complexes [L2M2]2+ have been prepared and structurally characterized, where L is a pyrazolate ligand with bulky 2,6‐dimethyl‐ or 2,6‐di(isopropyl)anilinomethyl side arms. Coordinating counter anions such as chloride can bind to axial sites of the dinickel species in a solvent‐dependent process, giving rise to five‐coordinate high‐spin metal ions. In the case of weakly coordinating anions, the metal ions are found in roughly square‐planar environments, and the structures are governed by the tendency of the bulky aryl groups to avoid each other, which forces the methyl or isopropyl substituents in the aryl 2‐ and 6‐positions to approach the metal ions from the axial directions. This leads to drastic low‐field shifts of the respective 1H NMR signals, e.g. δ = 7.86 ppm for the isopropyl −CH which comes in close proximity to the low‐spin nickel(II) center. The relevance of such low‐field NMR resonances of protons close to the axial sites of d8 metal ions for possible three‐center four‐electron M···H−C hydrogen bonds involving the filled d orbital of the metal ion is discussed. In the present case, attractive M···H interactions are assumed to be of no major significance. This was corroborated by the structure of a further [L2Ni2]2+ type complex where the anilinomethyl side arms bear only a single 2‐isopropyl group, which was found rotated away from the metal. Additional spectroscopic and electrochemical properties of the various complexes are reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Spontaneous and mitomycin C‐induced micronuclei in peripheral blood reticulocytes from severely malnourished rats
Authors: Ortiz Rocío , Medina Hilda , Rodríguez Leonor , González‐Márquez Humberto , Cortés Edith
Published: March 2004

Severe malnutrition caused by deficiencies in protein, calorie, and micronutrient intake is widely distributed throughout the world and is a particular problem in developing countries. Animal models have been useful for studying the effects of malnutrition under different experimental conditions. In this study, we have evaluated the effect of malnutrition on the frequency of spontaneous and mitomycin C (MMC)‐induced micronuclei in the peripheral blood of rats measured using a flow cytometric analysis technique. Neonatal rats were experimentally malnourished during lactation and assayed at weaning (21 days of age). The malnourished rats weighed 49.2% less than well‐nourished controls and had lower concentrations of serum protein, triglycerides, and cholesterol. In rats not treated with MMC, the frequency of micronucleated reticulocytes (MN‐RETs) was 1.6 times greater in malnourished rats than in well‐nourished rats (0.48% ± 0.16% vs. 0.31% ± 0.09%). The mean MN‐RET frequency measured 32 hr after treatment with single i.p. doses of 0.5, 0.75, or 1.0 mg/kg of MMC was 0.60 ± 0.10 vs. 0.84 ± 0.14, 1.21 ± 0.52 vs. 2.36 ± 0.47, and 2.50 ± 0.06 vs. 4.64 ± 1.14 for well‐nourished vs. malnourished rats, respectively. Statistical comparisons indicate significant differences between the two groups of rats at all doses tested. Malnourishment and MMC treatment had no significant effects on the frequencies of RETs or micronucleated normochromatic erythrocytes. The data indicate that protein‐calorie malnutrition during lactation is associated with increased frequencies of MN‐RETs, which are indicative of chromosome damage. These findings suggest that malnutrition could result in greater susceptibility to environmental damage. Environ. Mol. Mutagen. 43:179–185, 2004. © 2004 Wiley‐Liss, Inc.
Genotoxicity modulation by cadmium treatment: Studies in the Drosophila wing spot test
Authors: Rizki Mostapha , Kossatz Elk , Creus Amadeu , Marcos Ricardo
Published: March 2004

The genotoxic activity of cadmium chloride (CC) has been evaluated in the somatic mutation and recombination test (SMART) in Drosophila melanogaster. In addition, its possible modulating effect on the genotoxicity of two known mutagenic agents, potassium dichromate (PDC) and ethyl methanesulfonate (EMS), was investigated. Three different types of combined treatments of CC with the two genotoxins were performed: pretreatment, cotreatment, and posttreatment. The SMART assay is based on the principle that loss of heterozygosity for the recessive markers, multiple wing hairs (mwh) and flare‐3 (flr3), leads to the formation of mutant clones in the imaginal disks of larvae, which are expressed as mutant spots on the wings of adult flies. Thus, after adult emergence, the wings of the adult flies were scored for the presence of single and/or twin spots. Our results show that CC alone was not effective in increasing the frequency of any of the three categories of spots (small, large, and twin). In the cotreatment experiments, CC increased the genotoxicity of PDC but it decreased the genotoxicity of EMS. No effects of CC were observed in the pretreatment or posttreatment experiments; however, only low concentrations of CC, PDC, and EMS were tested in the pretreatment assays due to the high toxicity of the treatment. Although our results with PDC are consistent with the hypothesis that cadmium can interfere with repair mechanisms, the EMS data suggest that other modulating mechanisms are also involved in the genotoxicity of this metal. Environ. Mol. Mutagen. 43:196–203, 2004. © 2004 Wiley‐Liss, Inc.
Industrial wastewater treatment in a membrane bioreactor: A review
Authors: Marrot B. , Barrios‐Martinez A. , Moulin P. , Roche N.
Published: March 2004

This paper provides a detailed literature review of wastewater treatment in a membrane bioreactor process (MBR) with special focus on industrial wastewater treatment. MBR systems are compared with conventional wastewater treatment systems. The characteristics of the bioreactor treatment process (biomass concentration and floc size, organic and mass loading rates, etc.) are examined. The membrane separation of microorganisms from the treated wastewater is discussed in detail. Problems of membrane fouling and membrane washing and regeneration, linked to activated sludge characteristics, are examined. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 59–68, 2004
Influence of start‐ups with fuel‐oil on the operation of electrostatic precipitators in pulverised coal boilers
Authors: Navarrete B. , Vilches L.F. , Cañadas L. , Salvador L.
Published: March 2004

This article describes the results of a series of tests carried out in a pilot fly ash electrostatic precipitation facility operating with real gases from a 550 MWe pulverized coal‐fired power station. The main goal of these tests was to determine the effect of boiler start‐ups on the performance of the electrostatic precipitator.

The tests were carried out during start‐ups of the power station boiler. All tests were carried out with the same fuel. An evaluation was made of the effect of the use of fuel‐oil as auxiliary fuel in start‐ups and shut‐downs of the boiler, and different electrostatic precipitator operation procedures were tested during start‐ups and shut‐downs.

The results of the experiments made it possible to assess the relative importance of different variables on the possible deterioration of the efficiency of the precipitator. Also evaluated were operational modes that have demonstrated an improvement in the performance of the precipitators after the transient stage of these operations. As a result of this study, a number of important operational recommendations are made on boiler start‐up and shut‐down procedures. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 29–38, 2004
Computations of two passing‐by high‐speed trains by a relaxation overset‐grid algorithm
Authors: Liu Jenn‐Long
Published: March 2004

This paper presents a relaxation algorithm, which is based on the overset grid technology, an unsteady three‐dimensional Navier–Stokes flow solver, and an inner‐ and outer‐relaxation method, for simulation of the unsteady flows of moving high‐speed trains. The flow solutions on the overlapped grids can be accurately updated by introducing a grid tracking technique and the inner‐ and outer‐relaxation method. To evaluate the capability and solution accuracy of the present algorithm, the computational static pressure distribution of a single stationary TGV high‐speed train inside a long tunnel is investigated numerically, and is compared with the experimental data from low‐speed wind tunnel test. Further, the unsteady flows of two TGV high‐speed trains passing by each other inside a long tunnel and at the tunnel entrance are simulated. A series of time histories of pressure distributions and aerodynamic loads acting on the train and tunnel surfaces are depicted for detailed discussions. Copyright © 2004 John Wiley & Sons, Ltd.
TNF‐α in vivo stimulates apoptosis in fibroblasts through caspase‐8 activation and modulates the expression of pro‐apoptotic genes
Authors: Alikhani Mani , Alikhani Zoubin , Raptis Markos , Graves Dana T.
Published: March 2004

Apoptosis of matrix producing cells is common among many inflammatory diseases. The goal of the present study was to examine the apoptotic effects of tumor necrosis factor‐α (TNF‐α) on fibroblastic cells in vivo and to investigate the role of different caspases in this process. This was accomplished in vivo by subcutaneous injection of TNF‐α in mice. The direct effects of TNF‐α on fibroblast apoptosis were studied in vitro with normal diploid human fibroblasts. The results indicate that TNF‐α in vivo induces apoptosis of fibroblasts. By RNase protection assay, we demonstrated that TNF‐α stimulates expression of 12 apoptotic genes. Fluorometric studies demonstrated that TNF‐α in vivo predominantly increased caspase‐8 and ‐3 activity and by use of specific inhibitors, the activation of caspase‐3 was shown to be initiated by caspase‐8 with only a minor contribution from caspase‐9. Thus, TNF‐α acts to modulate the expression of many genes that favors apoptosis of fibroblastic cells, which is dependent mostly upon signaling through caspase‐8. © 2004 Wiley‐Liss, Inc.
G protein‐coupled receptor agonist‐stimulated expression of ATF3/LRF‐1 and c‐myc and comitogenic effects in hepatocytes do not require EGF receptor transactivation
Authors: Nilssen Laila S. , Ødegård John , Thoresen G. Hege , Molven Anders , Sandnes Dagny , Christoffersen Thoralf
Published: March 2004

Several agonists acting on G protein‐coupled receptors (GPCR) enhance the mitogenic effect of epidermal growth factor (EGF) in rat hepatocytes, through mechanisms that have only partially been clarified. Results in various cells have led to the idea that a major mechanism for GPCR‐mediated stimulation of cell growth is transactivation of receptor tyrosine kinases, particularly the EGF receptor (EGFR), leading to rapid phosphorylation of the EGFR and activation of downstream signaling pathways. In the present study cultured rat hepatocytes were exposed to various GPCR agonists, including vasopressin, angiotensin II (Ang.II), norepinephrine, or prostaglandin F2α (PGF2α). None of these agents increased the phosphorylation of the EGFR or the docking protein Shc. Furthermore, we examined the effect of the GPCR agonists on the expression of two early response genes believed to be involved in growth activation. The GPCR agonists increased the mRNA expression of c‐myc, and also of activating transcription factor 3 (ATF3)/liver regeneration factor‐1 (LRF‐1), which is a novel finding. Finally, the selective EGFR inhibitor AG1478 did not suppress the activation of extracellular signal‐regulated kinase 1/2 (ERK1/2) or the induction of c‐myc or ATF3/LRF‐1 by the GPCR agonists, and did not prevent the comitogenic effects induced by these agents, while it blocked the effect of EGF on these responses. The results suggest that GPCR agonists induce expression of ATF3/LRF‐1 and c‐myc and exert comitogenic effects through mechanisms that do not require EGFR transactivation. © 2004 Wiley‐Liss, Inc.
Cartilage‐derived morphogenetic proteins enhance the osteogenic protein‐1‐induced osteoblastic cell differentiation of C2C12 cells
Authors: Yeh Lee‐Chuan C. , Tsai Alicia D. , Zavala Michelle C. , Lee John C.
Published: March 2004

Previous studies have shown that osteogenic protein‐1 (OP‐1; also known as BMP‐7) induces differentiation of the pluripotent mesenchymal cell line C2C12 into osteoblastic cells. OP‐1 also alters the steady‐state levels of messenger RNA (mRNA) encoding for the cartilage‐derived morphogenetic proteins (CDMPs) in C2C12 cells. In the present study, the effects of exogenous CDMPs on bone cell differentiation induced by OP‐1 in C2C12 cells were examined. Exogenous CDMP‐1, ‐2, and ‐3 synergistically and dose‐dependently enhanced OP‐1 action in stimulating alkaline phosphatase (AP) activity and osteocalcin (OC) mRNA expression. AP staining studies revealed that the combination of OP‐1 and CDMP enhanced OP‐1 action by stimulating those cells that had responded to OP‐1 and not by activating additional cells. The combination did not change the mRNA expression of the BMPs and their receptors. CDMP‐1 enhanced the suppression of the OP‐1‐induced expression of the myogeneic differentiation regulator MyoD. CDMP‐1 and OP‐1 alone stimulated Smad5 protein expression, but the combination of OP‐1 and CDMP‐1 stimulated synergistically Smad5 protein expression. Thus, one mechanism of the observed synergy involved enhancement of the induced Smad5 protein expression. At the same protein concentration, CDMP‐1 is most potent in enhancing OP‐1 activity in inducing osteoblastic cell differentiation of C2C12 cells. CDMP‐3 is about 80% as potent as CDMP‐1, and CDMP‐2 is the least potent (about 50% of CDMP‐1). © 2004 Wiley‐Liss, Inc.
Immunotherapy with autologous tumor cells engineered to secrete Tag7/PGRP, an innate immunity recognition molecule
Authors: Larin Sergey S. , Korobko Elena V. , Kustikova Olga S. , Borodulina Olga R. , Raikhlin Natan T. , Brisgalov Igor P. , Georgiev Georgii P. , Kiselev Sergei L.
Published: March 2004

Background

Recent studies indicate that the innate component of immune defense plays an important role in the establishment of antigen‐specific immune response. We have previously isolated a novel mouse gene tag7/PGRP that was shown to be involved in the innate component of the immune system, and its insect homologue is an upstream mediator of Toll signaling in Drosophila.

Methods

Transiently or stably genetically modified mouse tumor cell lines expressing Tag7 were used. Tumor growth rate and animal survival were analyzed. Possible effector cells involved in tumor suppression were detected immunohistochemically.

Results

Transfection of mammary gland adenocarcinoma cells with the tag7 cDNA did not alter their growth rate in vitro but diminished their tumorogenicity in vivo in syngeneic and immunodeficient animals. Increased incidence of apoptosis was registered in the modified tumors. Transient expression of Tag7 by mouse melanoma M3 cells elicited protective immunity against parental tumor cells. Immunohistochemical analysis revealed that tumors after immunization with the genetically modified cells were infiltrated with Mac1+ cells, B220+ cells, and NK cells. Using nude mice we observed rejection of modified cells, but did not detect memory formation.

Conclusions

We can conclude that secretion of the Tag7 protein by genetically modified cells can induce mobilization of antigen‐presenting cells and innate effectors. Memory mechanisms are mediated by T cell response. For the first time our results demonstrate that local secretion of Tag7—the molecule involved in innate immunity—may play an important role in the induction of effective antitumor response in mice. Copyright © 2004 John Wiley & Sons, Ltd.
Rescue of TNFα‐inhibited neuronal cells by IGF‐1 involves Akt and c‐Jun N‐terminal kinases
Authors: Kenchappa Prashanth , Yadav Ajay , Singh Gurvinder , Nandana Srinivas , Banerjee Kakoli
Published: March 2004

Proinflammatory cytokines, especially tumor necrosis factor α (TNFα), is a pleiotropic mediator of a diverse array of physiologic and neurologic functions and is upregulated during various inflammatory and neurodegenerative diseases. A common survival response during such situations is the increased expression of the hormone insulin‐like growth factor 1 (IGF‐1). Although it was thought previously that the mechanisms of TNFα and IGF‐1 action were unrelated, it has been shown that low doses of TNFα can inhibit the survival effects of IGF‐1 in mouse cerebellar granule neurons. We used a neuronal cell line SH‐SY5Y, which underwent apoptosis in response to TNFα and this process could be reversed substantially by IGF‐1. Crosstalk between signaling pathways of these two factors was found at various points downstream of their signal transduction. To determine the mechanisms of IGF‐1‐mediated rescue, we looked at the MAP kinases, which are known to be involved in IGF‐1 as well as TNFα signaling. The c‐Jun N‐terminal kinase pathway, which is known normally to promote cell death, was found to actually promote survival of TNFα‐mediated cell death. Inhibiting the c‐Jun survival pathway completely reversed the rescue mediated by IGF‐1. In addition, the Akt pathway played an equally important role in this rescue. © 2004 Wiley‐Liss, Inc.
Redesigning computer call center work: a longitudinal field experiment
Authors: Workman Michael , Bommer William
Published: March 2004

Computer technology call centers provide technical assistance to customers via the telephone to solve computer hardware and software problems. The simultaneous demands for technical and customer service skills often place strain on call center employees, frequently producing poor job attitudes. We utilized a field experiment (N = 149) with a randomly assigned pretest–posttest and control group design to compare three interventions' effectiveness on employee job attitudes in a computer technology call center: Intervention 1 focused on aligning organizational structures; Intervention 2 focused on increasing employee involvement in work processes (high‐involvement); and Intervention 3 implemented autonomous work teams.

We found that high‐involvement work processes produced the most potent effects on job satisfaction and organizational commitment attitudes, as well as on performance (i.e., improved customer satisfaction scores, increased closed problems, reduced problems escalated, and fewer repeat calls). Further, we found that group work preference moderated the results between the group‐oriented interventions and employees' job satisfaction. Under high involvement and in autonomous work teams, high preferences for group work resulted in greater job satisfaction than when employees had lower preferences for group work. However, preferences for group work were not associated with increased organizational commitment in either intervention. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluation of pedotransfer functions predicting hydraulic properties of soils and deeper sediments
Authors: Wagner Bernhard , Tarnawski Vlodek R. , Stöckl Michael
Published: March 2004

Eight pedotransfer functions (PTF) originally calibrated to soil data are used for evaluation of hydraulic properties of soils and deeper sediments. Only PTFs are considered which had shown good results in previous investigations. Two data sets were used for this purpose: a data set of measured pressure heads vs. water contents of 347 soil horizons (802 measured pairs) from Bavaria (Southern Germany) and a data set of 39 undisturbed samples of tertiary sediments from deeper ground (down to 100 m depth) in the molasse basin north of the Alps, containing 840 measured water contents vs. pressure head and unsaturated hydraulic conductivity. A statistical analysis of the PTFs shows that their performance is quite similar with respect to predicting soil water contents. Less satisfactory results were obtained when the PTFs were applied to prediction of water content of sediments from deeper ground. The predicted unsaturated hydraulic conductivities show about the same uncertainty as for soils in a previous study. Systematic deviations of predicted values indicate that an adaptation of the PTFs to the specific conditions of deeper ground should be possible in order to improve predictions.
Variability of CO2 and N2O emissions during freeze‐thaw cycles: results of model experiments on undisturbed forest‐soil cores
Authors: Teepe Robert , Ludwig Bernard
Published: March 2004

The amounts of N2O released in periods of alternate freezing and thawing depend on site and freezing conditions, and contribute considerably to the annual N2O emissions. However, quantitative information on the N2O emission level of forest soils in freeze‐thaw cycles is scarce, especially with regard to the direct and indirect effect of tree species and the duration of freezing. Our objectives were (i) to quantify the CO2 and N2O emissions of three soils under beech which differed in their texture, C and N contents, and humus types in freeze‐thaw cycles, and (ii) to study the effects of the tree species (beech (Fagus sylvatica L.) and spruce (Picea abies (L.) Karst.)) for silty soils from two adjacent sites and the duration of freezing (three and eleven days) on the emissions. Soils were adjusted to a matric potential of –0.5 kPa, and emissions were measured in 3‐hr intervals for 33 days. CO2 emissions of all soils were similar in the two freeze‐thaw cycles, and followed the temperature course. In contrast, the N2O emissions during thawing differed considerably. Large N2O emissions were found on the loamy soil under beech (Loam‐beech) with a maximum N2O emission of 1200 μg N m–2 h–1 and a cumulative emission of 0.15 g N m–2 in the two thawing periods. However, the sandy soil under beech (Sand‐beech) emitted only 1 mg N2O‐N m–2 in the two thawing periods probably because of a low water‐filled pore space of 44 %. The N2O emissions of the silty soil under beech (Silt‐beech) were small (9 mg N m–2 in the two thawing periods) with a maximum emission of 150 μg N m–2 h–1 while insignificant N2O emissions were found on the silty soil under spruce (0.2 mg N m–2 in the two thawing periods). The cumulative N2O emissions of the short freeze‐thaw cycles were 17 % (Sand‐beech) or 22 % (Loam‐beech, Silt‐beech) less than those of the long freeze‐thaw cycles, but the differences between the emissions of the two periods were not significant (P ≤ 0.05). The results of the study show that the amounts of N2O emitted in freeze‐thaw cycles vary markedly among different forest soils and that the tree species influence the N2O thawing emissions in forests considerably due to direct and indirect impacts on soil physical and chemical properties, soil structure, and properties of the humus layer.
Miniaturised sample preparation of fatty foodstuffs for the determination of polychlorinated biphenyls
Authors: Ramos Juan‐José , González M.‐José , Ramos Lourdes
Published: March 2004

A miniaturised analytical method allowing the exhaustive extraction of environmentally relevant polychlorinated biphenyls (PCBs) from fatty foodstuffs and the purification of the extracts in a single step has been developed. After dispersion of the freeze dried sample on silica modified with 44% (w/w) of sulphuric acid, the mixture was packed in a glass column on top of a multilayer silica column used for removal of the lipids and biogenic co‐extracted material. Using this arrangement, a complete sample preparation can be accomplished by two successive 10 min static extractions with hexane followed by a brief dynamic step to ensure purging of the sample and sorbents. The analytical method showed a satisfactory performance, with recoveries of the endogenous PCBs studied in the 81–134% range of those found using a more conventional off‐line procedure, even though as small an amount of sample as 0.1 g was used. Detection limits by gas chromatography with micro‐electron capture detection (GC–ECD) were in all cases lower than 0.3 ng/g sample (freeze dried basis) and the repeatability of the complete analytical procedure better than 14% (except for PCB 167). When combined with GC and ion trap detection in the tandem mass spectrometry mode, the miniaturised method has been proved to be a valuable alternative to the more expensive high resolution mass spectrometry for fast screening of PCBs 77, 126, and 169, even if these congeners were not isolated from the bulk of PCBs.
Sample preparation followed by HPLC under harmless 100% aqueous conditions for determination of oxytetracycline in milk and eggs
Authors: Furusawa Naoto
Published: March 2004

A simple and hazardous chemical‐free method for the high‐performance liquid chromatographic determination of oxytetracycline (OTC) residues in milk and eggs has been developed. Sample preparation consists in homogenization with an aqueous solution by means of a handheld ultrasonic homogenizer followed by centrifugal ultrafiltration. HPLC is performed with an isocratic aqueous mobile phase and a photo‐diode array detector. Average recoveries of OTC (0.05, 0.1, and 0.2 μg mL–1 for milk; 0.1, 0.2, and 0.4 μg mL–1 for eggs) were ≥ 84% with relative standard deviations of ≤ 2.3%. The total time required for the analysis of one sample and LOQs were < 30 min and < 0.1 μg mL–1, respectively. In all the processes, no organic solvents or hazardous reagents were used.
Separation and determination of active components in Radix Salviae miltiorrhizae and its medicinal preparations by nonaqueous capillary electrophoresis
Authors: Chen An Jia , Zhang Ji You , Li Cun Hong , Chen Xiao Feng , Hu Zhi De , Chen Xing Guo
Published: March 2004

A nonaqueous capillary electrophoresis (NACE) method was developed for simultaneous assay of three bioactive components (1: cryptotanshinone; 2: tanshinone IIA, and 3: tanshinone I) in Radix Salviae miltiorrhizae and in its herbal preparations for the first time. After optimization of separation conditions, a buffer of 250 mmol L–1 ammonium acetate containing 30% acetonitrile and 1.0% acetic acid (V : V) in methanol was selected for separating the three analytes, but baseline separation of tanshinon I and tanshinone IIA was not obtained. Therefore second‐order derivative electropherograms were applied for resolving overlapping peaks. Regression equations revealed good linear relationships (correlation coefficients 0.9943–0.9991) between peak heights in second‐order derivative electropherograms and concentrations of the three analytes. The relative standard deviations (RSD) of the migration times and the peak height of the three constituents were in the range of 0.81–0.88% and 0.34–1.13% (intra‐day), 1.57–1.86% and 3.05–5.52% (inter‐day), respectively. The recoveries of three constituents ranged from 90.2 to 108.5%. The results indicated that baseline separation of the analytes was sometimes hard to obtain and second‐order derivative electropherograms were applicable for the resolving and analysis of overlapping peaks.
Prenatal diagnosis of an extra der(4) resulting from a complex maternal chromosome translocation
Authors: Migliori Maria Valeria , Pettinari Antonella , Ciaschini Anna Maria , Piermattei Paola , Pigliapoco Francesco , Discepoli Giancarlo
Published: March 2004

We report the prenatal diagnosis of an extra der(4) resulting from 4:2 malsegregation of a maternal balanced complex translocation involving chromosomes 4, 10, and 11. The woman was referred for amniocentesis because of recurrent miscarriages. Fluorescence in situ hybridization was performed in order to characterize the complex chromosome rearrangement. Following genetic counselling, the couple decided to terminate the pregnancy. Copyright © 2004 John Wiley & Sons, Ltd.
Molecular screening of the ZFHX1B gene in prenatally diagnosed isolated agenesis of the corpus callosum
Authors: Espinosa‐Parrilla Yolanda , Encha‐Razavi Férechté , Attié‐Bitach Tania , Martinovic Jelena , Morichon‐Delvallez Nicole , Munnich Arnold , Vekemans Michel , Lyonnet Stanislas , Amiel Jeanne
Published: March 2004

Objective

Agenesis of the corpus callosum (ACC) is the most common malformation of the central nervous system and may be associated with mental retardation. ACC is found in 40% of the cases of Mowat–Wilson syndrome (MWS), a polytopic embryonic defect including a distinctive facial gestalt, severe mental retardation, epilepsy and postnatal microcephaly as constant features. Other manifestations involve Hirschsprung disease, cardiac defects, renal abnormalities and hypospadias. Among this broad spectrum of malformations recently associated with haploinsufficiency of the zinc finger homeobox 1B gene (ZFHX1B), ACC can therefore be the only feature to be detected prenatally. Thus, we studied a group of 18 fetuses terminated for ACC and performed mutational analysis of the ZFHX1B gene in six selected cases.

Methods

Diagnosis of agenesis of the ACC was performed by prenatal echography survey. Screening for ZFHX1B deletions was performed by poly (CA) microsatellite markers studies and real‐time semi‐quantitative PCR. Mutational analysis was performed by single‐strand conformation polymorphisms analysis (SSCP).

Results

Neither deletion encompassing the ZFHX1B locus nor mutation could be detected in any of the six fetuses analysed.

Conclusion

ZFHX1B is not a major gene in isolated ACC. However, analysis of MWS should be considered in the differential diagnosis of ACC, especially when the facial features raise the possibility of MWS. Copyright © 2004 John Wiley & Sons, Ltd.
Crystallization and orientation development in fiber and film processing of polypropylenes of varying stereoregular form and tacticity
Authors: Choi Dongman , White James L.
Published: March 2004

We investigated the crystallization and orientation development in melt spinning and tubular blown film extrusion of several different types of polypropylenes, including conventional high tacticity isotactic polypropylenes (iPP) and metallocene catalyst low tacticity iPPs and syndiotactic polypropylenes (sPP). The fiber and film samples were characterized by wide‐angle X‐ray diffraction (WAXD), birefringence and differential scanning calorimetry (DSC). In melt spinning iPP, we found that the mesomorphic structure of iPP is more readily formed in lower tacticity fibers, and significant amounts of hexagonal β‐form crystals are found in low tacticity iPP fibers spun at high draw‐down ratios. Low tacticity iPP fibers exhibited a significant decrease in the crystalline chain‐axis orientation at high draw‐down ratios, resulting from increased epitaxially branched lamellae. Melt‐spun sPP fibers exhibit Form I helical structure at low spinning speeds and Form III zigzag all trans structure at high spinning speeds. We found that the level of spinline stress is the governing factor for this structural change. Melt‐spun sPP fibers exhibit much higher chain‐axis (c‐axis) orientation factors (fc) and lower birefringence than iPP fibers spun at the same spinline stresses. In tubular blown sPP films, the a‐axis of Form I unit cell tends to orient perpendicular to the film surface, while the b‐axis of monoclinic α unit cell does so in iPP blown films.
Characterization of polyethylene terephthalate films drawn in hot water
Authors: Zumailan A. , Dargent E. , Saiter J. M.
Published: March 2004

Sorbed water molecules in PET (around 1% in mass) lead to classic plasticizing effects, basically evidenced by a decrease of the glass transition (Tg) and of the cold crystallisation (Tc) temperatures with increasing water content. During drawing of dry PET film and depending on the draw ratio, the initial amorphous phase is oriented at first, then a strain‐induced crystallisation appears. This work deals with the conjugate effects of drawing and water sorption in PET films drawn in hot water. Differential scanning calorimetry and birefringence measurements shown that drawing performed in hot water leads to modifications of Tg and Tc without modification of the degree of crystallinity. Moreover, the formation of water clusters is observed when the strain‐induced crystalline phase occurs.
Blends, hydrogen bonds, and orientation: Understanding the role of interactions
Authors: Brisson Josée
Published: March 2004

A review of past and present studies on orientation, rheology, and FTIR investigations on a hydrogen bond–forming polymer, poly(vinyl phenol) (PVPh), and its blends with polyethylene oxide (PEO), poly(methyl methacrylate) (PMMA), and poly(vinyl methyl ether) (PVME) is presented. Orientation is analyzed on the basis of deformation‐induced orientation and relaxation. For deformation, it is proposed from recent molecular modeling studies that orientation is similar for flexible backbone polymers of the types studied. To investigate relaxation, dynamical rheology analysis was performed previously on PVPh/PEO blends and global molecular weight between entanglement, Me, and chain friction ζ were estimated. Me remained close to that of the polymer forming the dominant network, a discontinuity being observed near 50 mole percent. Friction coefficient exhibited a maximum near that of the orientation function of this system. Near‐infrared measurements also showed a maximum in the number of interchain hydrogen bonds at this concentration, although broader than that of orientation or of the friction coefficient. For strongly interacting blends, it is proposed that a break in orientation behavior would be associated with the dominant network present, and therefore to Me, whereas ζ will dictate whether orientation decreases or increases in a given network domain.
Dynamics and criteria for bubble instabilities in a single layer film blowing extrusion
Authors: Kim Seungoh , Fang Yunli , Lafleur Pierre G. , Carreau Pierre J.
Published: March 2004

In this paper, the performance of a new in‐line scanning camera system for the study of various bubble instabilities in film blowing extrusion is critically evaluated. Three commercial film‐grade polyethylenes, LmPE, LLDPE and LDPE, were used to generate the bubble instabilities. Reliable and objective criteria for differentiating various bubble instabilities such as draw resonance, helicoidal instability, and frost line height instability are proposed by using the new device. Detailed dynamics of each bubble instability was carefully investigated as a function of time in a broad range of the take‐up ratio (TUR), blow‐up ratio (BUR) and frost line height (FLH). In addition, effects of melt temperature and mass flow rates on dynamics of the bubble instabilities are discussed. It was found that the new system could capture the main characteristics of all bubble instabilities quantitatively. It was also found that magnitude and periodicity of radius variation during draw resonance of LmPE decreased as TUR increased at constant FLH and BUR. This implies that the origin of draw resonance in film blowing seems to be different from that observed in fiber spinning. In the case of helicoidal instability, eccentricity, which defines the deviation of the bubble center from the die center, decreased as TUR increased. However, the bubble could not be stabilized as expected. A graphical quantification approach to determine the stable zone in the bubble stability map is also discussed.
Fiber draw using draw pins under isothermal conditions
Authors: Bechtel S. E. , Vohra S. , Jacob K. I.
Published: March 2004

Using the governing equations developed from earlier work, we analyze a commercially relevant fiber drawing process where draw pins are used for localizing and enhancing the fiber draw. Inclusion of a draw pin introduces the possibility of unloading in the fiber, resulting in the additional complexity of elastic‐plastic fiber characteristics in the analysis. In the absence of unloading, the stress in the fiber monotonically increases, so that only the elastic response of the fiber enters into the analysis. In this work, we analyze an isothermal two stage drawing process with a draw pin in the second draw zone. Various possibilities of draw are analyzed which show that the total draw is in general distributed between the first and the second roller as well as on the pin. The offset location of the pin is shown to have a significant effect on the distribution of the draw. As this offset is increased, the nature of the draw on second roller changes from loading, to neither loading nor unloading at a critical offset, to unloading.
PBT/PET conjugated fibers: Melt spinning, fiber properties, and thermal bonding
Authors: Rwei Syang‐Peng , Jue Zhi‐Feng , Chen Frank L.
Published: March 2004

This work examines the PBT/PET sheath/core conjugated fiber, with reference to melt spinning, fiber properties and thermal bonding. Regarding the rheological behaviors in the conjugated spinning, PET and PBT show the smallest difference between their melt‐viscosity at temperatures of 290°C and 260°C respectively, which has been thought to represent optimal spinning conditions. The effect of processing parameters on the crystallinity of core material‐PET was observed and listed. In order of importance, these factors are the draw ratio, the heat‐set temperature, and the drawing temperature. The crystallinity of sheath material‐PBT, however, can be considered to be constant, independent of any processing parameters. The bulk orientation, rather than the crystallinity of PET core, dominates the tenacity of PBT/PET sheath/core fiber. Moreover, heat‐set treatment after drawing is recommended to yield a highly oriented conjugated fiber. With respect to thermal bonding, PBT/PET conjugated fibers processed via high draw ratio but low‐temperature heat setting can form optimal thermal bonds at a constant bonding temperature of 10°C above the Tm of PBT.
Electroless plating of copper on fluorinated polyimide films modified by surface graft copolymerization with 1‐vinylimidazole and 4‐vinylpyridine
Authors: Wang W. C. , Vora R. H. , Kang E. T. , Neoh K. G.
Published: March 2004

Electroless plating of copperviaa tin‐free activation process was carried out effectively on two types of fluorinated polyimide (FPI) films modified by UV‐induced surface graft copolymerization with N‐containing monomers, such as 1‐vinylimidazole (VIDz) and 4‐vinyl pyridine (4VP). The graft copolymerization of VIDz and 4VP was carried out on the argon (Ar) plasma‐pretreated FPI filmsviaa solvent‐free process under atmospheric conditions. X‐ray photoelectron spectroscopy (XPS) results showed that the VIDz graft‐copolymerized FPI surface (the VIDz‐g‐FPI surface) and 4VP graft‐copolymerized FPI surface (the 4VP‐g‐FPI surface) were much more susceptible to the electroless deposition of metalsviathe Sn‐free process than the pristine FPI surfaces, and the FPI surfaces modified by Ar plasma pretreatment alone. T‐peel adhesion strengths above 9 N/cm were achieved for the electrolessly deposited copper on both VIDz‐g‐FPI surfaces (the Cu/VIDz‐g‐FPI assemblies) and 4VP‐g‐FPI surfaces (the Cu/4VP‐g‐FPI assemblies). These adhesion strength values were much higher than those obtained for assemblies involving electrolessly deposited copper on pristine or on Ar plasma pretreated FPI films. The high adhesion strength of the Cu/VIDz‐g‐FPI and Cu/4VP‐g‐FPI assemblies was attributed to the synergistic effect of spatial interactions of the grafted VIDz or 4VP polymer chains with the copper atoms, and the fact that the VIDz or 4VP polymer chains were covalently tethered on the FPI surfaces. XPS results also revealed that the Cu/VIDz‐g‐FPI and Cu/4VP‐g‐FPI assemblies delaminated by cohesive failure inside the FPI films.
Effects of electron beam irradiation on poly(ethylene 2,6‐naphthalate)/poly(ethylene terephthalate) blends
Authors: Kim Jun Young , Kim Oh Seung , Kim Seong Hun , Jeon Han Yong
Published: March 2004

The effect of electron beam (EB) irradiation on the properties and compatibility of poly(ethylene 2,6‐naphthalate) (PEN)/poly(ethylene terephthalate) (PET) blends was investigated. Upon EB irradiation, PEN/PET blends underwent transesterification reactions, resulting in the formation of more random copolymers from the original binary pair. The degree of transesterification increased with dose rate, and all of the irradiated blends exhibited a single glass transition temperature. This indicated that transesterification reactions promoted by EB irradiation led to the formation of a single phase. Transesterification reactions promoted by EB irradiation led to more random copolymers, and the reduced regularity in the irradiated blends decreased the melting temperature. A higher degree of randomness and lower number‐average sequence lengths for the blend systems indicated that a more random chain structure was formed in the blends. The rheological measurements demonstrated that the irradiated PEN/PET blends were miscible. EB irradiation could promote transesterification reaction, thus enhancing the compatibility of PEN/PET blends.
Determining a significant change in protein expression with DeCyder™ during a pair‐wise comparison using two‐dimensional difference gel electrophoresis
Authors: Karp Natasha A. , Kreil David P. , Lilley Kathryn S.
Published: March 2004

Two‐dimensional difference gel electrophoresis (DIGE) is a tool for measuring changes in protein expression between samples involving pre‐electrophoretic labeling with cyanine dyes. Here we assess a common method to analyze DIGE data using the DeCyder™ software system. Experimental error was studied by a series of same sample comparisons. Aliquots of sample were labeled with N‐hydroxyl succinimidyl ester‐derivatives of Cy2, Cy3, and Cy5 dyes and run together on one gel. This allowed assessment of how experimental error influenced differential expression analysis. Bias in the log volume ratios was observed, which could be explained by differences in dye background. Further complications are caused by significant gel‐to‐gel variation in the spot volume ratio distributions. Using DeCyder™ alone results in an inability to define ratio thresholds for 90 or 95% confidence. An alternative normalization method was thus applied which resulted in improved data distribution and allowed greater sensitivity in analysis. When combined with a standardizing function, this allowed gel‐independent thresholds for 90% confidence. The new approach, detailed here, represents a method to greatly improve the success of DIGE data analysis.
The Human Proteome Organization Plasma Proteome Project pilot phase: Reference specimens, technology platform comparisons, and standardized data submissions and analyses
Authors: Omenn Gilbert S.
Published: March 2004

A comprehensive, systematic characterization of cirolating proteins in health and disease will greatly facilitate development of biomarkers for prevention, diagnosis, and therapy of cancers and other diseases. The Human Proteome Organization Plasma Proteome Project pilot phase aims to (1) compare the advantages and limitations of many technology platforms; (2) contrast reference specimens of human plasma (ethylenediaminetetra acetic acid, heparin, citrate‐anticoagulated) and serum, in terms of numbers of proteins identified and any interferences with various technology platforms; and (3) create a global knowledge base/data repository.
Prostate cancer cells generated during intermittent androgen ablation acquire a growth advantage and exhibit changes in epidermal growth factor receptor expression
Authors: Hobisch Alfred , Fiechtl Matthias , Sandahl‐Sorensen Boe , Godoy‐Tundidor Sonia , Artner‐Dworzak Erika , Ramoner Reinhold , Bartsch Georg , Culig Zoran
Published: March 2004

BACKGROUND

Intermittent androgen ablation is a palliative treatment option for advanced prostate cancer which is associated with less side effects, improved quality of life of patients, and reduced costs. Regulation of growth and survival of prostate cancer cells during intermittent androgen withdrawal has not been studied in appropriate models yet.

METHODS

Two cycles of androgen withdrawal and supplementation were performed in human prostate cancer cells LNCaP in vitro. Proliferation of prostate cancer cell sublines established after intermittent androgen withdrawal was assessed in the absence or presence of epidermal growth factor (EGF) by protein determination. Cell cycle was analyzed with a flow cytometer. EGF was measured in the supernatants of LNCaP sublines with a commercial ELISA. EGF receptor mRNA and protein were determined by real‐time PCR and Western blot, respectively.

RESULTS

Basal proliferation rate of all newly generated LNCaP sublines increased over that of the parental LNCaP cell line. The highest stimulation of proliferation by exogenous EGF was observed in parental LNCaP cells. In each LNCaP derivative established during intermittent androgen withdrawal, the percentage of cells in the S phase of cell cycle was higher than that in parental LNCaP cells. EGF levels did not increase during intermittent androgen ablation. The expression of EGF receptor protein decreased following each cycle of androgen ablation and increased subsequently after androgen supplementation. EGF receptor (EGFR) mRNA was regulated in a similar manner in LNCaP derivatives established during the second cycle of intermittent withdrawal.

CONCLUSIONS

Changes in the expression of the EGF receptor occur during intermittent androgen ablation but they cannot be solely responsible for increased basal proliferation. Alternatively, other ligands and receptors of the EGF system may become overexpressed during prolonged withdrawal and supplementation of androgenic hormones in prostate cancer therapy. © 2004 Wileey‐Liss, Inc.