bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical simulation for electrochemical cultivation of iron oxidizing bacteria
Authors: Matsumoto Norio , Yoshinaga Hisao , Ohmura Naoya , Ando Akikazu , Saiki Hiroshi 
Published: November 2004

AbstractA numerical simulation model was constructed for electrochemical cultivation of iron oxidizing bacterium, Thiobacillus ferrooxidans, based on Monod's dual limitation equation. In this model, two limiting factors were examined, low supply of Fe(II) ion and dissolved oxygen, from empirical viewpoints. The simulation model was constructed taking into consideration the energy balance based on the amount of the electronic flow from the electrode to bacteria via an iron ion, and then to oxygen. The model consisted of a logarithmic bacterial growth phase during the first three days, followed by a plateau and growth limitation thereafter. The predicted results were in agreement with the actual growth under electrochemical cultivation. It was predicted the growth limiting factor would be changed from insufficient supply of Fe(II) ions to that of oxygen by decreasing the value of oxygen transfer constant K, which correlated with the aeration rate. The optimum aeration rate was determined for the ideal electrochemical cultivation. The algorithm described here can be used in any electrochemical cultivation by modifying the parameters for each system. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 17–23, 2002; DOI 10.1002/bit.10173
Quantitative analyses of anaerobic wastewater treatment processes: Identifiability and parameter estimation
Authors: Noykova Nelly , Müller Thorsten G. , Gyllenberg Mats , Timmer Jens 
Published: November 2004

AbstractWe investigated the problem of identifying the parameters of a nonlinear fifth order model describing the population dynamics of two main bacterial groups in an anaerobic wastewater treatment process. In addition to addressing problems concerning structural and practical identifiability, we also analyzed how mathematical descriptions of bacterial population dynamics can model real data. Using three data sets recorded under different experimental conditions, we estimated important biochemical parameters and demonstrated that our model could describe the data successfully. Parameters, which are simultaneously determined using information from all three experiments, have more reliable estimates. We conclude that, after appropriate estimation, this model can be used for optimization and the control of continuous processes. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 89–103, 2002; DOI 10.1002/bit.10179
Enhancement of shikonin production in single‐ and two‐phase suspension cultures of Lithospermum erythrorhizon cells using low‐energy ultrasound
Authors: Lin Lidong , Wu Jianyong 
Published: November 2004

AbstractThis work demonstrates the use of low‐energy ultrasound (US) to enhance secondary metabolite production in plant cell cultures. Suspension culture of Lithospermum erythrorhizon cells was exposed to low‐power US (power density ≤113.9 mW/cm3) for short periods (1–8 min). The US exposure significantly stimulated the shikonin biosynthesis of the cells, and at certain US doses, increased the volumetric shikonin yield by about 60%–70%. Meanwhile, the shikonin excreted from the cells was increased from 20% to 65%–70%, due partially to an increase in the cell membrane permeability by sonication. With combined use of US treatment and in situ product extraction by an organic solvent, or the two‐phase culture, the volumetric shikonin yield was increased more than two‐ to threefold. Increasing in the number of US exposures during the culture process usually resulted in negative effects on shikonin yield but slight stimulation of shikonin excretion. US at relatively high energy levels caused slight cell growth depression (maximum 9% decrease in dry cell weight). Two key enzymes for the secondary metabolite biosynthesis of cells, phenylalanine ammonia lyase and p‐hydroxybenzoic acid geranyltransferase, were found to be stimulated by the US. The US stimulation of secondary metabolite biosynthesis was attributed to the metabolic activity of cells activated by US, and more specifically, the defense responses of plant cells to the mechanical stress of US irradiation. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 81–88, 2002; DOI 10.1002/bit.10180
Screening for improved cell performance: Selection of subclones with altered production kinetics or improved stability by cell sorting
Authors: Böhm Ernst , Voglauer Regina , Steinfellner Willi , Kunert Renate , Borth Nicole , Katinger Hermann 
Published: November 2004

AbstractOne of the major problems in the biotechnology industry is the selection of cell lines well suited for production of biopharmaceutical proteins. Usually, the most important selection criterion is the cell specific production rate. Nevertheless, a good producer cell line should have a number of additional advantageous properties, which allow the cell line to perform well in the type of bioreactor chosen for the process. However, the time and work required to select for high production rates as well as the lack of methods to specifically select for other cellular properties, usually prevents researchers from including such criteria into their screening program.With the Single Cell Secretion Assay it is possible to measure the specific production rates of individual cells by catching secreted product in an artificial matrix applied to the cell surface. Flow cytometric cell sorting then allows selection of rare cells with high production rates, which occur at frequencies as low as 10−6. By combining this method with culture conditions that bring out a desired cellular property, we were able to isolate subclones with similar production rates, but improved performance from a recombinant Chinese hamster ovary cell line producing a human monoclonal antibody. The two desired cellular properties screened for were a non‐growth associated production kinetic and improved stability in the absence of selective pressure. © 2004 Wiley Periodicals, Inc.
Enzymatic resolution for the preparation of enantiomerically enriched D‐β‐heterocyclic alanine derivatives using Escherichia coli aromatic L‐amino acid transaminase
Authors: Cho Byung‐Kwan , Park Hyung‐Yeon , Seo Joo‐Hyun , Kinnera Koteshwar , Lee Bon‐Su , Kim Byung‐Gee 
Published: November 2004

AbstractAn enzymatic resolution was carried out for the preparation of enriched β‐heterocyclic D‐alanine derivatives using Escherichia coli aromatic L‐amino acid transaminase. The excess of pyrazole, imidazole, or 1,2,4‐triazole reacted with methyl‐2‐acetamidoacrylate in acetonitrile in the presence of potassium carbonate at 60°C, directly leading to make the potassium salt of the corresponding N‐acetyl‐β‐heterocyclic alanine derivatives. After the acidic deprotection of the N‐acetyl group, 10 mM of racemic pyrazolylalanine, triazolylalanine, and imidazolylalanine were resolved to D‐pyrazolylalanine, D‐triazolylalanine, and D‐imidazolylalanine with 46% (85% ee), 42% (72% ee), and 48% (95% ee) conversion yield in 18 h, respectively, using E. coli aromatic L‐amino acid transaminase (EC 2.6.1.5). Although the three β‐heterocyclic L‐alanine derivatives have similar molecular structures, they showed different reaction rates and enantioselectivities. The relative reactivities of the transaminase toward the β‐heterocyclic L‐alanine derivatives could be explained by the relationship between the substrate binding energy (E, kcal/mol) to the enzyme active site and the distance (δ, Å) from the nitrogen of α‐amino group of the substrates to the C4′ carbon of PLP‐Lys258 Schiff base. As the ratio of the substrate binding energy (E) to the distance (δ) becomes indicative value of kcat/KM of the enzyme to the substrate, the relative reactivities of the β‐heterocyclic L‐alanine derivatives were successfully correlated with E/δ, and the relationship was confirmed by our experiments. © 2004 Wiley Periodicals, Inc.
The effect of environmental innovations on employment changes: an econometric analysis
Authors: Rennings Klaus , Ziegler Andreas , Zwick Thomas 
Published: November 2004

AbstractThis paper examines the determinants of employment changes due to an environmental innovation of an establishment. The data stem from telephone surveys in five European countries. 1594 interviews have been realized with environmentally innovative establishments representing the European industry and service sector. Based on results of discrete choice models, we show that if the most important environmental innovation is a product or service innovation it has a significantly positive effect on the probability of an increase in employment compared with the probability of no noticeable change. In contrast, if the most important environmental innovation is an end‐of‐pipe innovation it has a significantly positive influence on employment decrease. Methodologically, we consider the multinomial logit model and several multinomial probit models. We find that the estimates of the parameters of the explanatory variables are very similar in the different approaches. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
Integrating Input from Multiple Signals: The VirA/VirG Two‐Component System of Agrobacterium tumefaciens
Authors: Mukhopadhyay Aindrila , Gao Rong , Lynn David G. 
Published: November 2004

AbstractBacteria, fungi, and plants exploit histidine sensor kinase/response regulators to mobilize complex responses to inputs as diverse as environmental stimuli and hormonal regulation. More than 50 such two‐component systems are found in many organisms, yet the mechanisms of signal perception, phosphotransfer regulation, and even the nature of the activating signals remain poorly defined. Here we resolve each phosphate transfer event in vivo for the Agrobacterium tumefaciens virulence two‐component system VirA/VirG. The input signals for this system are known, and the complex autocatalytic regulation of the signaling components has been removed. Two separate and independent phosphotransfer events are resolved, an initial ATP→sensorHis∼PO4→receiver∼PO4, that may be activated by xenognostic sugar/low pH, and a subsequent ATP→His∼PO4→VirG∼PO4 that requires xenognostic phenol activation. The identification of these separate pathways places biochemical limits on the regulated steps in this two‐component signal transduction module and further extends the model of how a single sensor is able to integrate multiple input stimuli.
A New Family of Synthetic Diterpenes that Regulates Cytokine Synthesis by Inhibiting IκBα Phosphorylation
Authors: Chao Ta‐Hsiang , Lam Thanh , Vong Binh G. , Través Paqui G. , Hortelano Sonsoles , Chowdhury Chinmay , Bahjat F. Rena , Lloyd G. Kenneth , Moldawer Lyle L. , Boscá Lisardo , Palladino Michael A. , Theodorakis Emmanuel A. 
Published: November 2004

AbstractThe synthesis and the biological evaluation of a new family diterpenes are presented. The synthetic studies were inspired by the structural framework of acanthoic acid (1) and yielded a family of compounds that were evaluated as anti‐inflammatory agents. Among them, compounds 2, 10, 12, and 16 exhibited a very low nonspecific cytotoxicity and inhibited the synthesis of TNF‐α with greater than 65 % efficacy at low micromolar concentrations. Cytokine‐specificity studies revealed that these compounds also inhibited the synthesis of the proinflammatory cytokines IL‐1β and IL‐6, while inhibition of IL‐1ra and IL‐8 synthesis was marginal and only occurred at high concentrations. Further studies, through EMSA and Western blot analyses, indicated that these compounds decreased the extent of phosphorylation of IκBα; this suggests that they exert their anti‐inflammatory profile by inhibiting NF‐κB‐mediated cytokine synthesis. These findings imply that these diterpenes represent promising leads for the development of novel anti‐inflammatory agents.
Liquid Oxygenation Improvement by Interaction of Bubbles and Vibration Fields
Authors: Grinis L. , Kholmer V. , Korin E. 
Published: November 2004

AbstractGas bubble motion characteristics and bubble size are important factors in various technological processes involving the interaction between liquid and gaseous systems. The present work studies the effect of vibration fields on the characteristics of bubble motion and bubble size. Bubble retention time in the liquid (rise velocity) and bubble mean diameter were chosen as main parameters effecting the oxygen mass transfer rate. A device for mechanical vibration of the aerated liquid was used. The influence of the device design parameters on the chosen bubble parameters is studied experimentally and discussed in this work. The results obtained show the possibility of controlling bubble retention time and bubble size by employing vibration fields. Thus, by applying rather simple techniques, one can considerably improve the process of liquid oxygenation.
Determination of Drying Characteristics and Effective Diffusivity for Sugar Cubes
Authors: Akosman C. 
Published: November 2004

AbstractIn this study, the drying characteristics of sugar cubes have been investigated. Drying experiments with sugar cubes were conducted in a laboratory‐type tray dryer at temperatures ranging from 45 to 95 °C and different air velocities (0.43, 0.56, and 0.7 m/s). Drying rates increased with the increase in temperature and air velocity. At high temperatures, the moisture content of the solid reached equilibrium moisture value in short time periods. Experimental data were analyzed by using the analytical solution of the unsteady‐state diffusion equation to determine the effective diffusivity in sugar cubes.
Decision pathway modeling
Authors: Myles Anthony J. , Brown Steven D. 
Published: November 2004

AbstractPattern recognition is playing an increasingly important role in chemical and biochemical data analysis. Many of these pattern recognition applications call for the discrimination of more than two classes of objects. Decision pathway modeling is proposed as a novel pattern recognition technique for multigroup classification. Decision pathway modeling decomposes the multigroup classification problem into simpler binary discrimination tasks, which are then reassembled into a single hierarchical architecture. To minimize effects of error propagation through the hierarchical architecture, dynamic pathway selection is proposed to adaptively direct the classification of new samples. Decision pathway modeling is compared against generalized multigroup and coupled binary discriminant techniques in terms of classification accuracy. The benefit of decision pathway modeling is shown to arise from the hierarchical decomposition and by the dynamic selection of classification pathways. Copyright © 2004 John Wiley & Sons, Ltd.
Active learning support vector machines for optimal sample selection in classification
Authors: Zomer Simeone , Del Nogal Sánchez Miguel , Brereton Richard G. , Pérez Pavón José L. 
Published: November 2004

AbstractLabelling samples is a procedure that may result in significant delays particularly when dealing with larger datasets and/or when labelling implies prolonged analysis. In such cases a strategy that allows the construction of a reliable classifier on the basis of a minimal sized training set by labelling a minor fraction of samples can be of advantage. Support vector machines (SVMs) are ideal for such an approach because the classifier relies on only a small subset of samples, namely the support vectors, while being independent from the remaining ones that typically form the majority of the dataset. This paper describes a procedure where a SVM classifier is constructed with support vectors systematically retrieved from the pool of unlabelled samples. The procedure is termed ‘active’ because the algorithm interacts with the samples prior to their labelling rather than waiting passively for the input. The learning behaviour on simulated datasets is analysed and a practical application for the detection of hydrocarbons in soils using mass spectrometry is described. Results on simulations show that the active learning SVM performs optimally on datasets where the classes display an intermediate level of separation. On the real case study the classifier correctly assesses the membership of all samples in the original dataset by requiring for labelling around 14% of the data. Its subsequent application on a second dataset of analogous nature also provides perfect classification without further labelling, giving the same outcome as most classical techniques based on the entirely labelled original dataset. Copyright © 2004 John Wiley & Sons, Ltd.
Frequency and type of serious infections in fludarabine‐refractory B‐cell chronic lymphocytic leukemia and small lymphocytic lymphoma
Authors: Perkins Jeremy G. , Flynn Joseph M. , Howard Robin S. , Byrd John C. 
Published: November 2004

AbstractBACKGROUNDTreatments for fludarabine‐refractory chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) are limited. Most new therapies being examined in fludarabine‐refractory patients have shown a high frequency of serious infection. Little data exist regarding the frequency of infections in this population treated with noninvestigational best supportive care therapies.METHODSThe infectious courses of 27 patients with fludarabine‐refractory CLL/SLL were retrospectively reviewed. Fludarabine‐refractoriness was defined as either relapse within six months of completion of or failure to respond to fludarabine treatment. Infections were documented after patients met National Cancer Institute criteria for further treatment. Serious infections were defined as infections mandating admission to the hospital for intravenous antibiotics.RESULTSPatient characteristics included: median age 67 years (range, 40–83), median 3 chemotherapy treatments (range, 1–8), and hypogammaglobulinemia in 73% of patients. Pneumocystis carinii prophylaxis was given to 89% of patients. Serious infections developed in 24 out of 27 patients (89%). Patients had a median of 2 admissions (range, 0–11) for serious infection occurring at a median of 4 months (range, 0–21) from onset of fludarabine‐refractoriness. The median frequency of admission for infection was 0.17 per month. Most common sites for infection in decreasing frequency were: respiratory tract, urinary tract, blood/sepsis, and soft tissues. Bacteria caused 69 out of 88 infections (78.4%); viruses (varicella‐zoster and herpes simplex) caused 11 out of 88 (12.5%); fungi caused 4 out of 88 (4.5%); and opportunistic infections caused 4 out of 88 (4.5%). Median survival was 13.0 months (range, 1–44+).CONCLUSIONSThe frequency of serious infections in patients with fludarabine‐refractory CLL/SLL is high. These findings are relevant to trials with new and highly effective agents for which the incidence of serious infections after treatment might otherwise appear to be prohibitively high. Cancer 2002;94:2033–9. © 2002 American Cancer Society.DOI 10.1002/cncr.10437
Proliferation marker KI‐S5 discriminates between favorable and adverse prognosis in advanced stages of neuroblastoma with and without MYCN amplification
Authors: Krams Matthias , Hero Barbara , Berthold Frank , Parwaresch Reza , Harms Dieter , Rudolph Pierre 
Published: November 2004

AbstractBACKGROUNDThe biologic behavior of neuroblastoma is notoriously variable, and even carefully elaborated prognostic models fail to predict the clinical course in a portion of cases. Because the proliferative activity is determined by the sum of all molecular imbalances that influence cell cycling, the authors investigated the potential prognostic relevance of the tumor growth fraction in neuroblastoma.METHODSA retrospective analysis was conducted on a cohort of 161 neuroblastoma patients with a median follow‐up period of 72.8 months. Tumors were classified according to Hughes typing and grading criteria. The proliferative index (PI) was assessed immunohistochemically on archival biopsy specimens using monoclonal antibody Ki‐S5 (Ki‐67), and the MYCN status was determined by means of Southern blot analysis.RESULTSThe PI, MYCN status, International Neuroblastoma Staging System (INSS) stage, International Neuroblastoma Pathology Classification grade, Hughes grade, and the patients' age at diagnosis were all found to be significant predictors of event free survival by univariate Kaplan–Meier analysis. However, the PI identified prognostically distinct subsets in higher tumor stages and Grade 2 and 3 neuroblastomas as well as tumors with unfavorable histology, and enabled risk stratification in tumors with and without MYCN amplification (P = 0.034 and 0.002, respectively). Multivariate Cox regression analysis selected INSS stage (relative risk [RR], 4.05; P < 0.0001) and the PI (RR, 2.49; P = 0.007) as the sole independent prognostic indicators, whereas MYCN entered the selection only after exclusion of the PI.CONCLUSIONSIt emerges that the PI as a single factor has greater predictive power than the MYCN status. Proliferation measurements therefore might significantly improve the accuracy of current prognostic models for neuroblastoma. Cancer 2002;94:854–61. © 2002 American Cancer Society.DOI 10.1002/cncr.10256
Abnormalities of chromosome bands 15q13‐15 in childhood acute lymphoblastic leukemia
Authors: Heerema Nyla A. , Sather Harland N. , Sensel Martha G. , La Mei K. L. , Hutchinson Raymond J. , Nachman James B. , Reaman Gregory H. , Lange Beverly J. , Steinherz Peter G. , Bostrom Bruce C. , Gaynon Paul S. , Uckun Fatih M. 
Published: November 2004

AbstractBACKGROUNDRecurring breakpoints in chromosome bands 15q13‐15 occur infrequently in leukemia. To the authors' knowledge, the clinical significance of these breakpoints in childhood acute lymphoblastic leukemia (ALL) has not been previously investigated.METHODSCentrally reviewed karyotypes of children with newly diagnosed ALL enrolled on Children's Cancer Group protocols from 1988 to 1995 formed the basis of the current report. Statistical analyses used chi‐square tests for homogeneity of proportions, and outcome was analyzed using life table methods and associated statistics.RESULTSOf 1946 cases with centrally reviewed and accepted cytogenetic analyses, 23 cases (1%) had breakpoints in chromosome bands 15q13‐15. Most patients with 15q13‐15 breakpoints had standard risk ALL, although breakpoints in 15q13‐15 occurred more frequently in infants than in older children. The majority of these patients (16 patients; 70%) had balanced 15q13‐15 rearrangements. Additional chromosomal abnormalities not involving 15q included abnormal 12p, abnormal 9p, Philadelphia chromosome, deletion 6q, and an 11q23 breakpoint. Thirteen (57%) 15q13‐15 breakpoints occurred in pseudodiploid karyotypes; five (22%) were in hyperdiploid karyotypes with 47‐50 chromosomes; two (9%) were in hyperdiploid karyotypes with > 50 chromosomes; and three (13%) were in hypodiploid karyotypes. Of the 23 patients with 15q13‐15 breakpoints, 21 were survivors, 18 survived event‐free for 2.2‐9.3 years, and 3 were alive 1 to 3 years after a relapse at time of writing.CONCLUSIONSThe current study suggests that genes at 15q13‐15 may be involved in the leukemogenesis of some cases of childhood ALL, but that with current intensive therapy such aberrations do not confer increased risk of treatment failure. Cancer 2002;94:1102–10. © 2002 American Cancer Society.DOI 10.1002/cncr.10325