bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of polymer surface affinity of novel antifouling agents
Authors: Dahlström Mia , Jonsson Per R. , Lausmaa Jukka , Arnebrant Thomas , Sjögren Martin , Holmberg Krister , Mårtensson Lena G.E. , Elwing Hans 
Published: March 2004

AbstractIn a previous study we found two agents, the α2‐agonist medetomidine ((±)‐4‐[1‐(2,3‐dimethylphenyl)ethyl]‐1H‐imidazole) and the α2‐agonist clonidine (2‐(2,6‐dichloroanilino)‐2‐imidazoline), that specifically and efficiently impede settlement of the barnacle Balanus improvisus, one of the most serious biofouling organisms in Swedish waters. Medetomidine, but not clonidine, is known to adsorb to solid polystyrene (PS) surfaces in the presence of salt, a feature that is of particular interest in attempts to develop an efficient antifouling surface. We show that medetomidine, but not clonidine, has a significant ability to adsorb to untreated (hydrophobic) PS in two different incubation media: filtered seawater (FSW) and deionized water (mQ). At negatively charged (hydrophilic) PS, medetomidine displays a strong interaction with the surface in both incubation media. At the hydrophilic PS, clonidine also displays a significant interaction with the surface when incubated in mQ and a weaker, but not significant, interaction when incubated in FSW. By studying the effects of time, incubation media, and pH on the adsorption of medetomidine and clonidine, we suggest that medetomidine is associated to hydrophobic PS by means of hydrophobic interactions, while the adsorption of medetomidine and clonidine to hydrophilic PS contains elements of electrostatic interaction. Using time‐of‐flight secondary ion mass spectroscopy (TOF‐SIMS) we detected only weak signals from medetomidine on the hydrophobic PS surfaces, while strong medetomidine signals were observed on hydrophilic PS. This suggests that the adsorbed medetomidine, to a greater extent, desorbed from the hydrophobic rather than from the hydrophilic PS surfaces during exposure to vacuum. The strong surface affinity of medetomidine on both types of surfaces and the preserved antifouling activity are valuable features in designing a marine coating. © 2004 Wiley Periodicals, Inc.
Purified tomato polygalacturonase activity during thermal and high‐pressure treatment
Authors: Verlent I. , Van Loey A. , Smout C. , Duvetter T. , Hendrickx M. E. 
Published: March 2004

AbstractExtracted tomato polygalacturonase was purified by cation‐exchange chromatography (and gel filtration) and characterized for molar mass, isoelectric point, as well as optimal pH for polygalacturonase activity. The enzymatic reaction of purified tomato polygalacturonase on polygalacturonic acid as substrate was investigated during a combined high‐pressure/temperature treatment in a temperature range of 25° to 80°C and in a pressure range of 0.1 to 500 MPa at pH 4.4 (the pH of tomato‐based products). The optimal temperature for initial tomato polygalacturonase activity in the presence of polygalacturonic acid at atmospheric pressure is about 55° to 60°C. The optimal temperature for initial tomato polygalacturonase activity during processing shifted to lower values at elevated pressure as compared with atmospheric pressure, and the catalytic activity of pure tomato polygalacturonase decreased with increasing pressure, which was mostly pronounced at higher temperatures. The elution profiles of the degradation products on high‐performance anion‐exchange chromatography indicated that for both thermal and high‐pressure treatment all oligomers were present in very small amounts in the initial stage of polygalacturonase activity. The amounts of monomer and small oligomers increased with increasing incubation times, whereas the amount of larger oligomers decreased due to further degradation. © 2004 Wiley Periodicals, Inc.
Purification and characterization of a chemotolerant alcohol dehydrogenase applicable to coupled redox reactions
Authors: Kosjek Birgit , Stampfer Wolfgang , Pogorevc Mateja , Goessler Walter , Faber Kurt , Kroutil Wolfgang 
Published: March 2004

AbstractThe purification and characterization of an organic solvent tolerant, NADH‐dependent medium‐chain secondary alcohol dehydrogenase (denoted sec‐ADH “A”) from Rhodococcus ruber DSM 44541 is reported. The enzyme can withstand elevated concentrations of organic solvents, such as acetone (up to 50% v/v) and 2‐propanol (up to 80% v/v). Thus, it is ideally suited for the preparative‐scale enantioselective oxidation of sec‐alcohol and the asymmetric reduction of ketones, using acetone and 2‐propanol, respectively, as cosubstrates for cofactor‐regeneration via a coupled‐substrate approach. The homodimeric protein was found to bear tightly bound zinc and displayed a molecular mass of 38 kDa per subunit as determined by SDS gel electrophoresis. The optimal temperature ranged from 30–50°C and the half‐life at 50°C was 35 h. In addition, excellent storage stability was found. The pH optimum for reduction is pH 6.5; pH 9.0 is preferred for oxidation. The enzyme followed a sequential reaction mechanism. The substrates are medium chain sec‐alcohols or (ω‐1)‐ketones; primary alcohols or aldehydes are not accepted. © 2004 Wiley Periodicals, Inc.
Mimicking the Escherichia coli cytoplasmic environment activates long‐lived and efficient cell‐free protein synthesis
Authors: Jewett Michael C. , Swartz James R. 
Published: March 2004

AbstractCell‐free translation systems generally utilize high‐energy phosphate compounds to regenerate the adenosine triphosphate (ATP) necessary to drive protein synthesis. This hampers the widespread use and practical implementation of this technology in a batch format due to expensive reagent costs; the accumulation of inhibitory byproducts, such as phosphate; and pH change. To address these problems, a cell‐free protein synthesis system has been engineered that is capable of using pyruvate as an energy source to produce high yields of protein. The “Cytomim” system, synthesizes chloramphenicol acetyltransferase (CAT) for up to 6 h in a batch reaction to yield 700 μg/mL of protein. By more closely replicating the physiological conditions of the cytoplasm of Escherichia coli, the Cytomim system provides a stable energy supply for protein expression without phosphate accumulation, pH change, exogenous enzyme addition, or the need for expensive high‐energy phosphate compounds. © 2004 Wiley Periodicals, Inc.
Glycoforms of β‐lactoglobulin with improved thermostability and preserved structural packing
Authors: Broersen Kerensa , Voragen Alphons G. J. , Hamer Rob J. , de Jongh Harmen H. J. 
Published: March 2004

AbstractIn this article we show how various degrees of glycosylation can be used to control the thermal stability of proteins. The primary amines of β‐lactoglobulin were glycosylated with glucose or fructose within a range of non‐denaturing reaction parameters. The modified fractions were characterized and analyzed for structural stability and hydrophobic exposure. The modification procedure gave rise to the production of glycoproteins with a well‐defined Gaussian distribution, where glucose appeared more reactive than fructose. The integrity of the secondary, tertiary, and quaternary structures remained unaffected by the modification procedure. However, upon heating the stability of the modified fractions increased up to 6 K. Here we demonstrate the effects on the thermodynamic properties of proteins by glycosylation; this work serves as a first step in understanding and controlling the process underlying aggregation of glycosylated proteins. © 2004 Wiley Periodicals, Inc.
Haloalkane hydrolysis by Rhodococcus erythropolis cells: Comparison of conventional aqueous phase dehalogenation and nonconventional gas phase dehalogenation
Authors: Erable Benjamin , Goubet Isabelle , Lamare Sylvain , Legoy Marie Dominique , Maugard Thierry 
Published: March 2004

AbstractBiofiltration of air polluted by volatile organic compounds is now recognized by the industrial and research communities as an effective and viable alternative to standard environmental technologies. Whereas many studies have focused on solid/liquid/gas biofilters, there have been fewer reports on waste air treatment using other biological processes, especially in a solid/gas biofilter. In this study, a comparison was made of the hydrolysis of halogenated compounds (such as 1‐chlorobutane) by lyophilized Rhodococcus erythropolis cells in a novel solid/gas biofilter and in the aqueous phase. We first determined the culture conditions for the production of R. erythropolis cells with a strong dehalogenase activity. Four different media were studied and the amount of 1‐chlorobutane was optimized. Next, we report the possibility to use R. erythropolis cells in a solid/gas biofilter in order to transform halogenated compounds in corresponding alcohols. The effect of experimental parameters (total flow into the biofilter, thermodynamic activity of the substrates, temperature, carbon chain length of halogenated substrates) on the activity and stability of lyophilized cells in the gas phase was determined. A critical water thermodynamic activity (aw) of 0.4 is necessary for the enzyme to become active and optimal dehalogenase activity for the lyophilized cells is obtained for an aw of 0.9. A temperature of reaction of 40°C represents the best compromise between stability and activity. Activation energy of the reaction was determined and found equal to 59.5 KJ/mol. The pH effect on the dehalogenase activity of R. erythropolis cells was also studied in the gas phase and in the aqueous phase. It was observed that pH 9.0 provided the best activity in both systems. We observed that in the aqueous phase R. erythropolis cells were less sensitive to the variation in pH than R. erythropolis cells in the gas phase. Finally, the addition of volatile Lewis base (triethylamine) in the gaseous phase and the action of the lysozyme in order to permeabilize the cells was found to be highly beneficial to the effectiveness of the biofilter. © 2004 Wiley Periodicals, Inc.
Recombinant protein purification from pea
Authors: Menkhaus Todd J. , Pate Cynthia , Krech Anthony , Glatz Charles E. 
Published: March 2004

AbstractTo assess the suitability of transgenic peas as a host for protein production from the perspective of ease of recovery, a strain containing recombinant β‐glucuronidase with poly(histidine) tail (GUSH6) was evaluated for solubility of the target protein in relation to native components (proteins, carbohydrates, and phenolics). Recovery of the recombinant GUSH6 from aqueous extracts by immobilized metal affinity chromatography with coupled Co2+ yielded a nearly pure product with IDA (enrichment factor (EF) = 260) or NTA (EF = 200) resin. Single‐step recoveries were also possible by isoelectric precipitation (EF = 4), polyelectrolyte precipitation (EF = 1.5), and anion‐exchange chromatography (EF = 3.1), but enrichment factors were low. © 2004 Wiley Periodicals, Inc.
Immobilization of DNAzyme as a thermostable biocatalyst
Authors: Ito Yoshihiro , Hasuda Hirokazu 
Published: March 2004

AbstractDeoxyribozyme (DNAzyme) carrying peroxidase activity was immobilized on two types of particles and the enzymatic activity was measured. The DNA recognizing porphyrin were prepared according to Travascio et al. ([1998] Chem Biol 5:505–517) and the interactions with hemin were investigated by ultraviolet absorbance and circular dichroism spectroscopies. The DNA interacted with hemin and significant conformational change was induced by the interaction. Therefore, the end of this DNA was modified with a thiol group and it was immobilized on thiol‐containing polysaccharide beads or on gold particles. The DNA immobilized on the gold particle showed activity catalyzing the peroxidation reaction. No significant reduction of activity was observed even after immobilization. The immobilized DNAzyme could be repeatedly utilized without significant loss of activity. In addition, heat treatment did not reduce the activity, although a protein enzyme, horseradish peroxidase, lost its activity after the heat treatment. The repertoire of DNAzyme is still currently limited. However, in the future the utilization of DNAzyme in the field of biotechnology will be important with the increase of discoveries of new functional DNAzymes. © 2004 Wiley Periodicals, Inc.
Effect of xylan and lignin removal by batch and flowthrough pretreatment on the enzymatic digestibility of corn stover cellulose
Authors: Yang Bin , Wyman Charles E. 
Published: March 2004

AbstractCompared with batch systems, flowthrough and countercurrent reactors have important potential advantages for pretreating cellulosic biomass, including higher hemicellulose sugar yields, enhanced cellulose digestibility, and reduced chemical additions. Unfortunately, they suffer from high water and energy use. To better understand these trade‐offs, comparative data are reported on xylan and lignin removal and enzymatic digestibility of cellulose for corn stover pretreated in batch and flowthrough reactors over a range of flow rates between 160° and 220°C, with water only and also with 0.1 wt% sulfuric acid. Increasing flow with just water enhanced the xylan dissolution rate, more than doubled total lignin removal, and increased cellulose digestibility. Furthermore, adding dilute sulfuric acid increased the rate of xylan removal for both batch and flowthrough systems. Interestingly, adding acid also increased the lignin removal rate with flow, but less lignin was left in solution when acid was added in batch. Although the enzymatic hydrolysis of pretreated cellulose was related to xylan removal, as others have shown, the digestibility was much better for flowthrough compared with batch systems, for the same degree of xylan removal. Cellulose digestibility for flowthrough reactors was related to lignin removal as well. These results suggest that altering lignin also affects the enzymatic digestibility of corn stover. © 2004 Wiley Periodicals, Inc.
Relation between the duration of remission and hyperglycemia during induction chemotherapy for acute lymphocytic leukemia with a hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone/methotrexate–cytarabine regimen
Authors: Weiser Mary Ann , Cabanillas Maria E. , Konopleva Marina , Thomas Deborah A. , Pierce Sherry A. , Escalante Carmen P. , Kantarjian Hagop M. , O'Brien Susan M. 
Published: March 2004

AbstractBACKGROUNDHyperglycemia, which is not uncommon during the treatment of acute lymphocytic leukemia (ALL), has been shown to be an independent predictor of adverse outcomes among hospitalized patients with undiagnosed diabetes; it also may have the potential to affect leukemic cell proliferation through altered metabolism. The purpose of the current study was to determine the prevalence of hyperglycemia during induction chemotherapy for ALL using a regimen comprised of hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (Hyper‐CVAD) and to determine its effect on survival, duration of disease remission, and treatment‐related complications.METHODSTwo hundred seventy‐eight adult patients with previously untreated ALL who achieved a complete remission with the hyper‐CVAD regimen were evaluated. Hyperglycemia was defined as ≥ 2 glucose determinations of ≥ 200 mg/dL during the first 30 days of induction chemotherapy. Induction chemotherapy was comprised of fractionated cyclophosphamide at a dose of 300 mg/m2 twice daily on Days 1–3, doxorubicin at a dose of 50 mg/m2 on Day 4, vincristine at a dose of 2 mg on Days 4 and 11, and dexamethasone at a dose of 40 mg on Days 1–4 and Days 11–14 (hyper‐CVAD). Hyper‐CVAD, given in odd‐number courses (Courses 1, 3, 5, and 7), was alternated with methotrexate and cytarabine (MTX/Ara‐C), given in even‐number courses (Courses 2, 4, 6, and 8). MTX/Ara‐C was comprised of MTX at a dose of 200 mg/m2 over 2 hours followed by 800 mg/m2 over 22 hours on Day 1, Ara‐C at a dose of 3 g/m2 every 12 hours for 4 doses over 2 days (Days 2 and 3), and intravenous methylprednisolone given at a dose of 50 mg twice daily on Days 1–3. The complete remission duration (CRD), survival, and treatment‐related complications were determined for patients with and without hyperglycemia; differences between the two groups were assessed using standard statistical methods.RESULTSHyperglycemia was found to occur in 103 patients (37%). Patients with hyperglycemia had a shorter median CRD (24 months vs. 52 months; P = 0.001) and a shorter median survival (29 months vs. 88 months; P < 0.001); they also were more likely to develop sepsis (16.5% vs. 8.0%; P = 0.03) or any complicated infection (sepsis, pneumonia, or fungal) (38.8% vs. 25.1%; P = 0.016) compared with patients without hyperglycemia.CONCLUSIONSPatients with hyperglycemia during induction chemotherapy for ALL with the hyper‐CVAD regimen were found to have a shorter CRD, experience a significant increase in overall mortality, and be at an increased risk for developing complicated infections. Cancer 2004. © 2004 American Cancer Society.
Effect of noisy carrier reference signal and interference on performance of MSK receiver
Authors: Stefanovic Mihajlo C. , Draca Dragan Lj. , Vidovic Aleksandra Z. 
Published: March 2004

AbstractThis paper considers the coherent detection of minimum shift keying signal and a degradation in error rate performance from ideal due to an interference and a phase discrepancy between the carrier of the received signal and the carrier of the receiver. The error rate is calculated for the simple receiver model with integrate‐and‐dump circuits. The reference carrier signal unsteadiness is presented by the probability density function of the first order non‐linear PLL phase error, while the uncertainty due to an interference is involved in the system model with a random phase of cosine signal that accompanied the useful signal. Copyright © 2004 John Wiley & Sons, Ltd.
Burst scheduling for differentiated services in optical burst switching WDM networks
Authors: Liu David Q. , Liu Ming T. 
Published: March 2004

AbstractOptical burst switching (OBS) is one of the most important switching technologies for future optical wavelength division multiplexing (WDM) networks and the Internet. The model of differentiated services has been proposed to support quality of service (QoS) in the IP‐based Internet. It is also very important to have differentiated service support in OBS networks. When the burst scheduling in an OBS network is set up appropriately, network can support differentiated services. In this paper, we proposed a new burst scheduling scheme, calleddifferentiated scheduling with identical priority offset time(DSIPO). In DSIPO, the same priority offset time is used for all the bursts destined to the same edge node regardless of their priorities. Differentiated services in terms of burst loss probability are achieved by processing the control packets of higher priority class bursts, thus reserving resources for their data bursts, more promptly upon their arrival than those of lower priority class bursts. Each intermediate (core) node can adjust the burst loss probabilities of various burst classes by choosing its owndifferentiated processing delayvalue for each priority class or its owndifferentiated processing delay differencevalue between any pair of adjacent priority classes. We model and analyse DSIPO in terms of the burst loss probability for each priority class with simulation validation. The performance of DISPO is evaluated by simulation. Copyright © 2004 John Wiley & Sons, Ltd.
Adaptive directional‐aware location update strategy
Authors: Tung Tracy , Jamalipour Abbas 
Published: March 2004

AbstractIn this paper, a new tracking strategy, the directivity‐aware location updating scheme was developed to better utilize the distinct characteristics of individual users on travelling directions. In this new adaptive scheme, an optimal distance‐based update threshold is selected according to the call‐to‐mobility ratio and a transitional directivity index, introduced to give indications of the mobile's travelling patterns. It is found that as far as mobility characteristics are concerned, the actual transitional direction of roaming mobiles plays a significant role in selecting the optimal threshold in addition to the usual perception about mobility rate. Its advantage becomes even more visible when an optimal threshold is not theoretically obtainable due to certain restrictions imposed by the network during times of high system loadings. Simulation results show that the additional information made available about roaming mobile's transitional directivity is critical to ensure that the best available sub‐optimal threshold is realizable. Other advances in this paper include the simplification of existing Markovian movement model. With the improved model presentation, the number of states necessary to simulate such memoryless movements is reduced. Consequently, the computational complexity involved is also lessened. Copyright © 2004 John Wiley & Sons, Ltd.
Exploring the performance of TCP vegas in mobilead hocnetworks
Authors: Papanastasiou Stylianos , Ould‐Khaoua Mohamed 
Published: March 2004

AbstractRecent research efforts in mobilead hocnetworks have concentrated on examining the behaviour of TCP Reno over variousad hocrouting protocols and have suggested a number of extensions to improve its performance. TCP Vegas, which takes a proactive approach to congestion avoidance, has not so far been examined as a viable alternative to TCP Reno in wireless environments and no effort has been made to analyse its performance over routing protocols for MANETs. This paper evaluates using extensive simulation experiments the performance behaviour of TCP Vegas over a proactive (destination sequenced distance vector) and two reactive (dynamic source routing andad hocon demand distance vector) routing protocols and compares it against that of TCP Reno. Copyright © 2004 John Wiley & Sons, Ltd.
N,N‐Dialkylcarbamato Lanthanide Complexes, a Series of Isotypical Coordination Compounds
Authors: Baisch Ulrich , Belli Dell’Amico Daniela , Calderazzo Fausto , Labella Luca , Marchetti Fabio , Merigo Alessandra 
Published: March 2004

AbstractThe preparations of the N,N‐dialkylcarbamato complexes with analytical formulae [Ln(O2CNR2)3] (Ln = Pr, Nd, Eu, Gd, Ho, Er, Yb, Lu, R = iPr; Ln = Nd, Eu, Gd, R = Bu; Ln = Nd, R = Et), using [LnCl3(ether)x] (ether = THF or dimethoxyethane, DME), NHR2, and CO2 are reported. X‐ray diffraction of the diisopropylcarbamato derivatives, including a reinvestigation of [Yb4(O2CNiPr2)12], showed these complexes to be tetranuclear and isotypical over a range of 12 atomic numbers. The lanthanide contraction has been evaluated based on the lengths of four different types of Ln−O bond. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
γ‐Linolenic acid content and fatty acid composition of Boraginaceae seed oils
Authors: Erdemoglu Nurgun , Kusmenoglu Senay , Vural Mecit 
Published: March 2004

AbstractEleven species of the Boraginaceae family collected in Turkey were analyzed with respect to the amount of γ‐linolenic acid as well as fatty acid composition. γ‐Linolenic acid was found in all species, except for Heliotropium lasiocarpum Fisch. & Mey. and Heliotropium dolosum De Not. Seed oil content ranged from 1.5% in H. lasiocarpum to 22.0% in Anchusa leptophylla ssp. leptophylla. The content of γ‐linolenic acid ranged from 1.7% of total fatty acids in Paracaryum racemosum (Schreber) Britten var. racemosum to 13.7% in A. leptophylla Roemer & Shultes ssp. leptophylla. According to data from our study, A. leptophylla ssp. leptophylla (13.7%), Anchusa azurea Miller var. azurea (11.9%) and Echium plantagineum L. (12.2%) might be considered as new sources of γ‐linolenic acid.