bluuebunny/crossref_metadata_2025_split huggingface dataset:
High‐Yield Production of Lutein by the Green Microalga Chlorella protothecoidesin Heterotrophic Fed‐Batch Culture
Authors: Shi Xian‐Ming , Chen Feng 
Published: September 2002

AbstractThe green microalga Chlorella protothecoideswas grown heterotrophically in batch mode in a 3.7‐L fermenter containing 40 g/L glucose and 3.6 g/L urea. In the late exponential phase, concentrated nutrients containing glucose and urea were fed into the culture, in which the nitrogen source was sufficient compared to carbon source. As a result, a maximum cell dry weight concentration of 48 g/L was achieved. This cell dry weight concentration was 28.4 g/L higher than that obtained in batch culture under the same growth conditions. In another cultivation run, the culture was provided with the same initial concentrations of glucose (40 g/L) and urea (3.6 g/L) as in the batch mode, followed by a relatively reduced supply of nitrogen source in the fed‐batch mode to establish a nitrogen‐limited culture. Such a modification resulted in an enhanced lutein production without significantly lowering biomass production. The cellular lutein content was 0.27 mg/g higher than that obtained in the N‐sufficient culture. The improvements were also reflected by higher maximum lutein yield, lutein productivity, and lutein yield coefficient on glucose. This N‐limited fed‐batch culture was successfully scaled up from 3.7 L to 30 L, and a three‐step cultivation process was developed for the high‐yield production of lutein. The maximum cell dry weight concentration (45.8 g/L) achieved in the large fermenter (30 L) was comparable to that in the small one (3.7 L). The maintenance of the culture at a higher temperature (i.e., 32 °C) for 84 h resulted in a 19.9% increase in lutein content but a 13.6% decrease in cell dry weight concentration as compared to the fed‐batch culture (30 L) without such a treatment. The enhancement of lutein production resulted from the combination of nitrogen limitation and high‐temperature stress.
Comparative Study of the Inactivation Kinetics of Pectinmethylesterase in Tomato Juice and Purified Form
Authors: Fachin Diana , Van Loey Ann M. , Nguyen Binh Ly , Verlent Isabel , Indrawati  , Hendrickx Marc E. 
Published: September 2002

AbstractPectinmethylesterase (PME) extracted from tomato fruit was purified by affinity chromatography. A single peak of PME activity was observed, presenting a molar mass of 33.6 kDa, an isoelectric point higher than 9.3, and an optimal temperature and pH for activity of 55 °C and 8.0, respectively. The processing stability of purified tomato PME in buffer solution was compared to PME stability in tomato juice. In both media, thermal inactivation of PME presented first‐order inactivation kinetics, PME in tomato juice being more heat‐labile than purified PME. Regarding high‐pressure treatment, tomato PME showed to be very pressure‐resistant, revealing an outspoken antagonistic effect of temperature and pressure. To avoid cloud loss in tomato juice, a time‐temperature treatment of 1 min at 76.5 °C was calculated in order to have a residual PME activity of 1 × 10−4U/mL.
Development of an Optimal Medium for Continuous Ferrous Iron Oxidation by Immobilized Acidothiobacillus ferrooxidansCells
Authors: Kim Tae Wan , Kim Chang Joon , Chang Yong Keun , Ryu Hee Wook , Cho Kyung‐Suk 
Published: September 2002

AbstractThis study was aimed at developing an immobilized bioreactor system in which long‐term continuous ferrous iron oxidation can be realized with no formation of jarosite, which causes clogging of support pores and reactor lines. For this purpose, a medium with no jarosite formation was developed first by selecting optimal nitrogen and phosphate sources and their concentrations. Then with the developed medium containing ammonium phosphate instead of ammonium sulfate and potassium phosphate, repeated batch and continuous operations of ferrous iron oxidation by Acidothiobacillus ferrooxidanscells immobilized in a depth filter were successfully performed for an extended period of time. For about 510 h of operation including 450 h of continuous operation at dilution rates of 0.1, 0.2, and 0.3 h‐1, no formation of jarosite and thus no clogging of the reactor system were observed. The maximum ferrous iron oxidation rate was as high as 2.6 g/(L·h) at a dilution rate of 0.3 h‐1.
Cultivation of Primary Porcine Hepatocytes in an OXY‐HFB for Use as a Bioartificial Liver Device
Authors: Jasmund Inka , Langsch Angelika , Simmoteit Robert , Bader Augustinus 
Published: September 2002

AbstractBioreactors being developed for bioartificial liver devices vary greatly in their construction. Until now, primary liver cells were cultivated either in sandwich configuration, as spheroids, or in special hollow fiber systems. Primary hepatocytes are demanding on their environment and have a high oxygen consumption. To get good results, optimal cultivation conditions are needed. The idea of the project was to investigate a new concept of an oxygenating hollow fiber bioreactor (OXY‐HFB). The OXY‐HFB should consist exclusively of oxygenating and internal heat exchange fibers to yield a simple and effective design. Primary liver cells were seeded on the surface of the fibers in the extrafiber space. Oxygen requirements and temperature control were supplied through the fibers. The culture medium was perfused through the extrafiber space and therefore brought into direct hepatocellular contact. The OXY‐HFB concept offers different advantages. A high cell density of 2.5 × 107cells/mL can be obtained. This results in a cell number of 2.5 × 109liver cells per bioreactor. Furthermore, the OXY‐HFB is easily handled because no incubator is required. To study the efficiency of this bioreactor technique, various parameters were investigated over a cultivation period of three weeks. These included urea synthesis, lactate formation, glucose elimination, albumin synthesis, oxygen level, and pH. Furthermore, the metabolites of diazepam were measured. The biochemical performance of the bioreactor remained stable over the investigated time period. These results demonstrate that porcine liver cells preserve their viability and primary metabolism in the OXY‐HFB over the complete period of study.
An Integrated Process for Mammalian Cell Perfusion Cultivation and Product Purification Using a Dynamic Filter
Authors: Castilho Leda R. , Anspach F. Birger , Deckwer Wolf‐Dieter 
Published: September 2002

AbstractIn the present work, a dynamic filter was employed to develop an integrated perfusion/purification process. A recombinant CHO cell line producing a human anti‐HIV IgG was employed in the experiments. In the first part of this work, the dynamic filter was fitted with conventional microfiltration membranes and tested as a new external cell retention device for perfusion cultivations. The filter was connected to a running perfusion bioreactor and operated for approximately 400 h at an average cell concentration of 10 million cells mL−1, whereby cell viability remained above 90% and no problems of sterility were experienced. In the second part of this work, the dynamic filter was employed to simultaneously carry out cell separation and product purification, using membrane adsorbers containing Protein A affinity ligands. An automated system was built, which integrated the features of an automated perfusion bioreactor and of a liquid chromatography system. The IgG was continuously adsorbed onto the affinity membranes and was periodically recovered through elution cycles. After connection of the filter, the system was operated for approximately 300 h, whereby three elution cycles were carried out. No progressive increase in transmembrane pressure was observed, indicating no membrane fouling problems, and the IgG was recovered practically free of contaminants in a 14‐fold concentrated form, indicating that the integrated, one‐step perfusion/purification process developed during this work is a promising alternative for the production of biologicals derived from mammalian cells.
Room‐Temperature Synthesis of l‐Alanine Using the Alanine Dehydrogenase of the Hyperthermophilic Archaeon Archaeoglobus fulgidus
Authors: Vadas Alexander J. H. , Schröder Imke , Monbouquette Harold G. 
Published: September 2002

AbstractAlanine dehydrogenase from the hyperthermophilic archaeon Archaeoglobus fulgiduswas used at room temperature for batch synthesis of l‐alanine by the reductive amination of pyruvate. The reaction mixture included yeast formate dehydrogenase for regeneration of NADH with formate as electron donor. The synthesis of l‐alanine at room temperature was accompanied by no detectable loss of alanine dehydrogenase activity over 139 h and ≥99% consumption of pyruvate. The total number of enzyme turnovers was 5.1 million. This work demonstrates the potential utility of novel hyperthermostable enzymes that can be both very active and highly stable at moderate temperature.
Quantitative estimation of global patterns of surface ocean biological productivity and its seasonal variation on timescales from centuries to millennia
Authors: Loubere Paul , Fariduddin Mohammad 
Published: September 2002

We present a quantitative method, based on the relative abundances of benthic foraminifera in deep‐sea sediments, for estimating surface ocean biological productivity over the timescale of centuries to millennia. We calibrate the method using a global data set composed of 207 samples from the Atlantic, Pacific, and Indian Oceans from a water depth range between 2300 and 3600 m. The sample set was developed so that other, potentially significant, environmental variables would be uncorrelated to overlying surface ocean productivity. A regression of assemblages against productivity yielded an r2 = 0.89 demonstrating a strong productivity signal in the faunal data. In addition, we examined assemblage response to annual variability in biological productivity (seasonality). Our data set included a range of seasonalities which we quantified into a seasonality index using the pigment color bands from the coastal zone color scanner (CZCS). The response of benthic foraminiferal assemblage composition to our seasonality index was tested with regression analysis. We obtained a statistically highly significant r2 = 0.75. Further, discriminant function analysis revealed a clear separation among sample groups based on surface ocean productivity and our seasonality index. Finally, we tested the response of benthic foraminiferal assemblages to three different modes of seasonality. We observed a distinct separation of our samples into groups representing low seasonal variability, strong seasonality with a single main productivity event in the year, and strong seasonality with multiple productivity events in the year. Reconstructing surface ocean biological productivity with benthic foraminifera will aid in modeling marine biogeochemical cycles. Also, estimating mode and range of annual seasonality will provide insight to changing oceanic processes, allowing the examination of the mechanisms causing changes in the marine biotic system over time.This article contains supplementary material.
Multivariate projection of ocean surface data onto subsurface sections
Authors: Fischer Martin 
Published: September 2002

A multivariate projection of ocean surface data onto subsurface fields is presented. The method is applied to the projection of sea surface height and sea surface temperature anomalies onto the three dimensional temperature field. The results are compared to the conventional univariate regression between sea surface height and the underlying temperature structure.The multivariate method clearly outperforms the univariate approach and succeeds in capturing the equatorial anomaly structures even during the early nineties, a period in which the univariate projection encounters great difficulties. A multivariate scheme projects onto linear combinations of different vertical modes, depending on the contribution of each input variable. Thus, vertical patterns, different not only in amplitude but also in shape can be affected, as opposed to the univariate case. During the ENSO cycle two different vertical temperature modes become dominant. To address both modes, two linearly independent variables are required. Therefore, the combination of SSH and SST contains additional information about the vertical temperature structure that cannot be extracted from either sea surface height measurements, or sea surface temperature only. This is of relevance in the context of ENSO predictions, and it may help to improve the initialization of ENSO forecast models.
Heat flow variations in a deep borehole near Sept‐Iles, Québec, Canada: Paleoclimatic interpretation and implications for regional heat flow estimates
Authors: Mareschal Jean‐Claude , Rolandone Frédérique , Bienfait Gérard 
Published: September 2002

A deep (> 2000m) borehole in the Sept‐Iles intrusion, on the north shore of the Saint Lawrence River, in Québec, Canada, was repeatedly logged for temperature. Systematic variations of the temperature gradient with depth are not correlated with the thermal conductivity. We interpreted the temperature profile as follows:(1) During the last glacial maximum, the temperature at the base of the ice sheet was cold (≈−5°C); (2) When the region was below sea level, between 10 and 5ky B.P., the ground surface temperature was warm (≈ 6°C); (3) The average ground surface temperature dropped to ≈ 2°C at 5ky B.P. when the region rebounded above sea level; (4) The long time averaged ground surface temperature before the last glacial maximum was ≈0 ‐ 1°C; (5) The reference heat flow (36 – 37mW m−2) is 4–5mW m−2 higher than estimated from the upper 1000m of the heat flow profile.This interpretation can not be extrapolated to the entire region covered by the Laurentide ice sheet. Except for extremely deep (> 1500m) boreholes, the small uncertainty (< 15%) affecting heat flow estimates can not be eliminated.
Daily streamflow conditions map now online
Authors: Lins Harry F. 
Published: September 2002

A new daily streamflow conditions map for the United States is now available online from the U.S. Geological Survey (USGS). The map depicts streamflow as a percentile of its longterm value for each day Located at http://water.usgs.gov/public/dwc/national_map.html, it is updated every 3 hours.The flows are grouped into seven color‐coded percentile categories. More than 2000 realtime stations from the USGS stream gaging network, each having at least 30 years of continuous records, are represented. Changes in daily streamflow over the past several weeks can be viewed in an animated sequence.
Legionellosis in a lung transplant recipient obscured by cytomegalovirus infection and Clostridium difficile colitis
Authors: Nichols L , Strollo D.C. , Kusne S. 
Published: September 2002

Abstract: A 52‐year‐old‐white male underwent double lung transplantation for severe emphysema due to alpha‐1‐antitrypsin deficiency and heavy tobacco use. Following a postoperative course complicated by renal insufficiency, pulmonary emboli, and Clostridium difficile colitis, he was discharged in stable condition. Two months later, he was admitted to a local hospital with a fever, abdominal pain, diarrhea, nausea, and dyspnea. Computerized tomography (CT) of the chest revealed bilateral pleural effusions. Sigmoidoscopy was grossly normal but biopsy demonstrated cytomegalovirus (CMV) colitis, and the patient was placed on intravenous ganciclovir. Over the next week, he became progressively hypoxemic and was transferred to the University of Pittsburgh Medical Center (post‐transplant day 81) for further evaluation. His medications on transfer included: ganciclovir, prednisone, tacrolimus, dapsone, fluconazole, ondansetron, lansoprazole, digoxin, and coumadin.
Ca2+entry blocking and contractility promoting actions of norbormide in single rat caudal artery myocytes
Authors: Fusi Fabio , Saponara Simona , Sgaragli Giampietro , Cargnelli Gabriella , Bova Sergio 
Published: September 2002

Aim of the present study was to investigate the effects of norbormide, a selective vasoconstrictor agent of the rat peripheral vessels, on the whole‐cell voltage‐dependent L‐type Ca2+current (ICa(L)) of freshly isolated smooth muscle cells from the rat caudal artery, using either the conventional or the amphotericin B‐perforated whole‐cell patch‐clamp method.Norbormide decreased L‐type Ca2+current in a concentration‐ and voltage‐dependent manner, without modifying the threshold and the maximum of the current‐voltage relationship. Norbormide‐induced ICa(L)inhibition was reversible upon wash‐out.Norbormide both shifted the voltage dependence of the steady‐state inactivation curve to more negative potentials by about 16 mV, without affecting the activation curve, and decreased the slope of inactivation. Norbormide, however, did not modify both the activation and the inactivation kinetics of the ICa(L).Norbormide decreased ICa(L)progressively during repetitive step depolarizations, with inhibition depending on the stimulation frequency (use‐dependent block) as well as on the holding potential.Addition of 50 μMnorbormide caused the contraction of all freshly isolated cells and also of those impaled with the perforated method, but not of those impaled with the conventional method (i.e. dialysed).In conclusion, these results prove norbormide to be a vascular L‐type Ca2+channel inhibitor, which preferentially acts on the inactivated and/or open state of the channel. In rat caudal artery smooth muscle, however, this mechanism does not result in a vasodilating effect since it is overwhelmed by the mechanism underlying norbormide‐induced vasoconstriction.British Journal of Pharmacology(2002)137, 323–328. doi:10.1038/sj.bjp.0704877
The underachieving child
Authors: Evans Bruce J. W. 
Published: September 2002

SummaryVisual factors in specific learning difficulties (SpLD) are reviewed. People with SpLD fail to achieve at a level that is commensurate with their intelligence. The commonest SpLD is dyslexia, which usually results from phonological processing/decoding deficits. Additionally, there are several optometric correlates of SpLD which may, in some cases, contribute to the learning difficulty. These correlates include binocular instability and a low amplitude of accommodation. Some people with reading difficulties and perceptual distortions/eyestrain can be helped by individually prescribed coloured filters. A visual processing anomaly is also often present in the form of a deficit of the transient visual system. The role of the optometrist is discussed.
Methods of investigating a visual deficit in dyslexia
Authors: Greatrex J. C. , Drasdo N. 
Published: September 2002

SummaryThe evidence for a visual deficit in dyslexia is inconclusive. We have developed several tests to investigate the parallel pathways of the visual system which can be applied to dyslexic subjects. Using the techniques of electroretinography, visual evoked potentials, adaptometry and contrast sensitivity, special protocols have been designed to elicit responses from these parallel pathways. These techniques are also applicable in the investigation of many pathological conditions, and of interest for pure research.
An A B C of glaucoma: apoptosis, blood flow and confocal imaging
Authors: Hosking Sarah L. 
Published: September 2002

SummaryA clear understanding and definition of the glaucomas continues to elude the clinician. Broadening awareness of the many risk factors in glaucoma, the wide variety of presentations of the disease and greater understanding of the pattern of progression will help to improve treatment protocols. In the meantime, the diagnosis and monitoring of the disease remains a huge clinical and financial burden. Modern imaging techniques permit quantitative stereometric assessment of the optic nerve head and nerve fibre layer, affording morphologic evaluation to complement clinical psychophysical investigation.
Non‐compliance in optometric practice
Authors: Claydon Bridget E. , Efron Nathan , Woods Craig 
Published: September 2002

SummaryThe purpose of this paper is to explore how some of the recent and future changes relating to the optometric profession could affect non‐compliant behaviour among patients. Non‐compliance has been widely documented and discussed in numerous health care fields and is understood to be the responsibility of both the practitioner and patient working in a health care partnership. At least one third of patients have been reported to be non‐compliant with health care recommendations which can result in the poor outcome of a treatment, secondary medical problems, dissatisfaction, frustration and the wasting of health resources. In recent years contact lens complications have been linked with non‐compliant behaviour with contact lens care and maintenance regimens which has led to several media scares over contact lens related hygiene risks and has heightened interest in the issue of non‐compliance in the field of optometry. Shared care schemes have already been adopted in some areas of the United Kingdom and if therapeutic pharmaceutical agents are introduced to the list of drugs permitted for use by optometrists in the future the issue of non‐compliance will become even more poignant. Every optometrist needs to be aware of the high probability of non‐compliant behaviour among patients, the consequences of this non‐compliance and the steps that can be taken to enhance compliance in different areas of eye‐care.
Scanning laser tomography: effect of change in keratometry values on retinal distance measures
Authors: Hosking Sarah , Flanagan John 
Published: September 2002

SummaryScanning laser tomography is an objective non‐invasive method for the three‐dimensional imaging of the eyein‐vivo. It has become a valuable tool in the diagnosis and monitoring of changes to the fundus and optic nerve head in diseases such as glaucoma. Optical errors should be eliminated where possible to improve accuracy and maximise the potential for the detection of subtle change due to disease progression. Alterations in the keratometry reading cause scaling changes in the (x,y) plane. This study demonstrated the importance of the keratometry value on retinal measurements. Accurate fundus measurements require input of the appropriate keratometry value for each subject, while for the detection of subtle change over time in longitudinal study, the keratometry reading should not be altered from baseline.
Glaucoma update: epidemiology and new approaches to medical management
Authors: Flanagan John G. 
Published: September 2002

SummaryGlaucoma describes a group of ocular conditions which involve progressive optic nerve damage associated with loss of visual function and, frequently, with elevated intraocular pressure. Recent estimates of worldwide prevalence predict that 67 million people will suffer from glaucoma by the year 2000. Although the clinical features of glaucoma are reasonably well described, the pathogenesis of optic nerve damage remains unclear. Intraocular pressure (IOP) is accepted as an important risk factor; however, it is clear that other factors play a role in the pathogenesis of the disease, and such factors may interact with IOP to greatly enhance its harmful effects. Many of the new therapeutic approaches to the stabilisation and potential cure of glaucoma attempt to address these non‐IOP factors. The aim of the following paper is to consider the implications of new estimates of disease prevalence, discuss theories related to optic nerve damage and outline new and future approaches to the medical management of the disease.