bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrolysis of lactose by free and immobilized β‐galactosidase from Thermus sp. strain T2
Authors: Ladero M. , Perez M.T. , Santos A. , Garcia‐Ochoa F. 
Published: November 2002

AbstractThe hydrolysis of lactose by a β‐galactosidase from the thermophilic microorganism Thermus sp. strain T2, both in solution and immobilized on a commercial silica‐alumina, has been studied. The enzyme has been previously produced by Escherichia coli JM101 harboring the plasmid pBGT1, which contains the codifying gene under the promoters lppP and lacPQ. The enzyme was immobilized on the support activated with tris‐hydroxymethylphosphine (THP). Activity and stability of the free and the immobilized enzyme towards pH and temperature were tested. To study the activity at different pH and temperature values, lactose was used as substrate. To check the stability, the enzyme was incubated either in buffer BP or in a solution of lactose in buffer BM at different pH and temperatures, being the remaining activity tested by withdrawing samples and determining their activity toward ONPG at 70°C in buffer BP. Afterward, runs were performed to obtain kinetic models adequate for the description of the hydrolysis of lactose by the free and the immobilized enzyme. These data were fitted to the kinetic models proposed (all based on the Michaelis–Menten mechanism) by non‐linear regression, being the models and their parameters compared to determine the effect of the immobilization on the kinetic behavior of the enzyme. Both the free and the immobilized enzyme are competitively inhibited by galactose, while glucose inhibited only the action of the free enzyme, in an uncompetitive way. The immobilization step seems to eliminate the inhibition by glucose. Moreover, the immobilization reduced to a half the inhibitory action of galactose. In general, the immobilization reduced the activity of the enzyme, but increased its thermal stability. Finally, a comparison between the kinetic behavior of this thermophilic enzyme and enzymes of mesophile microorganisms previously studied by us (E. coli and K. fragilis) and by other authors (Aspergillus niger) is performed. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81:241–252, 2003.
Enclosed outdoor photobioreactors: Light regime, photosynthetic efficiency, scale‐up, and future prospects
Authors: Janssen Marcel , Tramper Johannes , Mur Luuc R. , Wijffels René H. 
Published: November 2002

AbstractEnclosed outdoor photobioreactors need to be developed and designed for large‐scale production of phototrophic microorganisms. Both light regime and photosynthetic efficiency were analyzed in characteristic examples of state‐of‐the‐art pilot‐scale photobioreactors. In this study it is shown that productivity of photobioreactors is determined by the light regime inside the bioreactors. In addition to light regime, oxygen accumulation and shear stress limit productivity in certain designs. In short light‐path systems, high efficiencies, 10% to 20% based on photosynthetic active radiation (PAR 400 to 700 nm), can be reached at high biomass concentrations (>5 kg [dry weight] m−3). It is demonstrated, however, that these and other photobioreactor designs are poorly scalable (maximal unit size 0.1 to 10 m3), and/or not applicable for cultivation of monocultures. This is why a new photobioreactor design is proposed in which light capture is physically separated from photoautotrophic cultivation. This system can possibly be scaled to larger unit sizes, 10 to >100 m3, and the reactor liquid as a whole is mixed and aerated. It is deduced that high photosynthetic efficiencies, 15% on a PAR‐basis, can be achieved. Future designs from optical engineers should be used to collect, concentrate, and transport sunlight, followed by redistribution in a large‐scale photobioreactor. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 193–210, 2003.
Kinetic analysis of enhanced thermal stability of an alkaline protease with engineered twin disulfide bridges and calcium‐dependent stability
Authors: Ikegaya Kazuo , Sugio Shigetoshi , Murakami Kohji , Yamanouchi Kouichi 
Published: November 2002

AbstractThe thermal stability of a cysteine‐free alkaline protease (Alp) secreted by the eukaryote Aspergillus oryzae was improved both by the introduction of engineered twin disulfide bridges (Cys‐69/Cys‐101 and Cys‐169/Cys‐200), newly constructed as part of this study, and by the addition of calcium ions. We performed an extensive kinetic analysis of the increased thermal stability of the mutants as well as the role of calcium dependence. The thermodynamic activation parameters for irreversible thermal inactivation, the activation free energy (ΔG‡), the activation enthalpy (ΔH‡), and the activation entropy (ΔS‡) were determined from absolute reaction rate theory. The values of ΔH‡ and ΔS‡ were significantly and concomitantly increased as a result of introducing the twin disulfide bridges, for which the increase in the value of ΔH‡ outweighed that of ΔS‡, resulting in significant increases in the value of ΔG‡. The enhancement of the thermal stability obtained by introducing the twin disulfide bridges is an example of the so‐called low‐temperature stabilization of enzymes. The stabilizing effect of calcium ions on wild‐type Alp is similar to the results we obtained by introducing the engineered twin disulfide bridges. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 187–192, 2003.
Fault tolerance in Clos–Knockout multicast ATM switch
Authors: Chan K. S. , Chan Sammy , Ko K. T. 
Published: November 2002

AbstractIn this paper, we propose a new architecture for multicast ATM switches with fault tolerant capability based on the Clos–Knockout switch. In the new architecture, each stage has one more redundant switch module. If one switch module is faulty, the redundant module would replace the faulty one. On the other hand, under the fault‐free condition, the redundant modules in the second and third stages will provide additional alternative internal paths, and hence improve the performance. The performance analysis shows that the cell loss probability is lower than the original architecture when all modules are fault free, and the reliability of the original architecture is improved. Copyright © 2002 John Wiley & Sons, Ltd.
Evaluating the expedited forwarding of voice traffic in a differentiated services network
Authors: Ziviani Artur , de Rezende José F. , Duarte Otto Carlos M. B. 
Published: November 2002

AbstractThe Differentiated Services architecture offers a scalable alternative to provide Quality of Service (QoS) to the new multimedia applications in the Internet. This paper aims at evaluating the delay and jitter experienced by voice traffic when handled by the Expedited Forwarding (EF) scheme. The analysis includes the effects of different packet scheduling mechanisms implementing EF and of the voice packet size. We also evaluate how efficiently each type of traffic uses an extra allocated bandwidth and the impact of traffic shaping. The results show that increasing the service rate share allocated to the EF aggregate does not significantly affect the competing best effort (BE) traffic. This holds as long as the BE traffic can use the bandwidth left unused by the EF traffic in idle periods. Copyright © 2002 John Wiley & Sons, Ltd.
Quality of offering on the world wide web
Authors: Mantzaridis G. , Papadimitriou G. I. , Pomportsis A. S. 
Published: November 2002

AbstractThe definition of quality in a ‘life’ environment, such as that of the World Wide Web has proven to have many, often conflicting interpretations. Factors such as the point of view, the expertise and type of usage of the critic can influence dramatically such a definition and its results. Thus, the key point is to distance oneself from single perspectives and obtain a complete picture of the system as a single entity working towards a specific goal. This paper is an attempt at creating a general model of quality procedures. It will concentrate mainly in customer service, system viability and quality of offering evaluation. Some of the material mentioned is based on adapted classical models that can be used equally to apply and observe standards of offerings in the wider WEB community. Copyright © 2002 John Wiley & Sons, Ltd.
Solid‐pseudopapillary tumor of the pancreas: A neoplasm with distinct and highly characteristic cytological features
Authors: Pettinato Guido , Di Vizio Dolores , Manivel J. Carlos , Pambuccian Stefan E. , Somma Pasquale , Insabato Luigi 
Published: November 2002

AbstractThe solid‐pseudopapillary tumor of the pancreas (SPTP) is an unusual low‐grade malignant epithelial tumor affecting predominantly adolescent girls and young women. Although approximately 500 cases of SPTP have been described in the last 40 yr, its pathogenesis remains uncertain. However, the clinical features of this neoplasm are very characteristic and SPTP must be suspected in any young woman with a cystic or partially cystic pancreatic mass. In this report, we describe the cytologic features of seven cases of SPTP investigated by preoperative fine‐needle aspirates. The analysis of the cytologic features in these cases and in 43 cases collected from the literature reveals that they are highly characteristic and quite distinct from those of other cystic or solid tumors of the pancreas. On this basis, a cytologic diagnosis of SPTP may be rendered with great confidence, not only in clinically typical examples, but also in unusual presentations, such as in older patients, in males, in ectopic locations, and in metastatic sites. Diagn. Cytopathol. 2002;27:325–334. © 2002 Wiley‐Liss, Inc.
Role for HPV testing in ASCUS: A cytologic‐histologic correlation
Authors: Crabtree Dwayne , Unkraut April , Cozens Donna , Smith Tina , Lucas Cinda , Pennington Donna , Chaney Lois , Nestok Blake , Robinson‐Smith Toni , Yassin Rawia 
Published: November 2002

AbstractHuman papilloma virus (HPV) Hybrid Capture® II testing was introduced at our institution in mid‐April, 2001. Relatively little data exists on the histologic follow‐up of “high‐risk HPV‐positive ASCUS” patients without a previous abnormal Pap result. The results of the cytologic–histologic correlation of 50 patients over an 11‐mo period are presented. Our results indicate that significant lesions may be discovered in patients of the “high‐risk HPV‐positive ASCUS” category who have no previous abnormal Pap history. Of the 50 patients presented in this study, histologic follow‐up demonstrated evidence of squamous carcinoma in one patient (2%), high‐grade squamous intraepithelial lesion (HSIL) in eight patients (16%), and low‐grade squamous intraepithelial lesion (LSIL) in 19 patients (38%). The other 22 (44%) showed chronic cervicitis, reactive changes, or no pathologic changes. These findings suggest a more aggressive clinical approach may be warranted in the management of new onset ASCUS positive for high risk HPV. Diagn. Cytopathol. 2002;27:382–386. © 2002 Wiley‐Liss, Inc.
Cystic change in metastatic lymph nodes: A common diagnostic pitfall in fine‐needle aspiration cytology
Authors: Üstün Melek , Risberg Björn , Davidson Ben , Berner Aasmund 
Published: November 2002

AbstractFine‐needle aspiration cytology (FNAC) of cystic metastases is a challenging diagnostic category and has been investigated in a limited number of malignancies and sites. The present study retrospectively reviewed 1,211 FNAC of superficial masses, including lymph nodes (1,102 aspirates), benign cystic lesions (64 aspirates), and lymphocysts (45 aspirates) with the aim of determining the tumors that cause cystic change in metastases. Cytology results from 1,102 lymph node aspirations were suspicious or positive for malignancy in 541 specimens (49.1%), benign in 230 (20.9%), and unsatisfactory in 331 (30%). There were 28 malignant aspirates demonstrating cystic change (5.2%). The tumor type that most frequently caused cystic change was thyroid papillary carcinoma (42.8% of cases), followed by squamous cell carcinoma (primary in the head and neck region 30.8% and in the skin 24%), tumors of unknown origin (6.3%), serous papillary carcinoma of the ovary or endometrium (4.8%), and malignant melanoma (2.1%). Cystic change was observed most commonly in the head and neck region lymph nodes (60%). The most challenging lesions to assess using FNAC were metastatic lymph nodes showing cystic change, accounting for six of the 16 false‐negative diagnoses and one false‐positive diagnosis. The results of this study suggest that cystic change in metastatic lymph nodes occurs in certain types of tumors and is an important cause of diagnostic error. FNAC should be repeated in case of suspicious hypocellular cystic aspirations, especially in patients with known malignancy. Diagn. Cytopathol. 2002;27:387–392. © 2002 Wiley‐Liss, Inc.
Cytologic analyses of spindle‐cell lesions of the thorax and retroperitoneum
Authors: Lin Oscar , Nogueira Zerbini Maria Claudia , Dias de Oliveira Latorre Maria do Rosário , Saigo Patricia E. 
Published: November 2002

AbstractThoracic and retroperitoneal spindle‐cell lesions represent a diagnostic challenge in the evaluation of fine‐needle aspiration (FNA) specimens. The challenge is due to the morphologic similarities and wide variety of different entities with spindle‐cell morphology in these two sites. The purpose of this study was to identify criteria helpful in the classification and differential diagnosis of spindle‐cell lesions in these two locations. A set of cytologic features was analyzed in 57 thoracic or retroperitoneal spindle‐cell lesions. Our results show that pleomorphism and abundant single cells were parameters associated with high‐grade tumors in univariate and multivariate analysis, while coarse chromatin pattern was significant only in a univariate analysis. The combination of absence of pleomorphism, rare single cells, tight cluster arrangement, fine chromatin pattern, and absence of macronucleoli was seen only in benign cases. Assessment of background material was helpful in the differential diagnosis and classification. Necrosis was only found in high‐grade cases. Diagn. Cytopathol. 2002;27:343–349. © 2002 Wiley‐Liss, Inc.
Atrophic vaginitis versus invasive squamous cell carcinoma on ThinPrep® cytology: Can the background be reliably distinguished?
Authors: Selvaggi Suzanne M. 
Published: November 2002

AbstractThe presence of pronounced squamous epithelial atrophy/atrophic vaginitis on cervicovaginal preparations can present diagnostic difficulties, particularly in the presence of a granular background. The purpose of this study was to compare and contrast the background material present on ThinPrep cytology in cases of atrophic vaginitis and invasive squamous cell carcinoma (SCC). Thirty‐three cases of atrophic vaginitis showed a heavy background of granular material containing acute inflammatory cells, apoptotic bodies, and fresh/crenated red blood cells. These findings were indistinguishable from those present in five cases of invasive SCC. The only significant finding was the presence of malignant squamous epithelial cells in the latter. Since the background material in pronounced squamous epithelial atrophy/atrophic vaginitis mimics that present in invasive SCC on ThinPrep cytology, close attention must be paid to the cells present on the slide in order to render an accurate diagnosis. Diagn. Cytopathol. 2002;27:362–364. © 2002 Wiley‐Liss, Inc.
Overexpression of p16INK4A in liquid‐based specimens (SurePath™) as marker of cervical dysplasia and neoplasia
Authors: Saqi Anjali , Pasha Theresa L. , McGrath Cindy M. , Yu Gordon H. , Zhang Paul , Gupta Prabodh 
Published: November 2002

AbstractHuman papillomavirus (HPV) is recognized as a causal agent for cervical carcinomas. Assimilation of HPV oncogenes E6 and E7 into the host DNA promotes upregulation of cyclin dependent kinase inhibitor (CDKI) p16INK4A, detectable by monoclonal antibody in the developing cervical cancer cells. The aim of this study was to 1) develop a protocol for p16INK4A immunocytochemical staining on SurePath™ preparations, and 2) determine its utility as an HPV marker on a spectrum of cervical reactive and neoplastic lesions. Seventy‐two specimens consisting of 28 nonneoplastic/nondysplastic cases (NN), one reactive glandular cells (RGC), 27 low‐grade squamous intraepithelial lesions (LSIL), 10 high‐grade squamous intraepithelial lesions (HSIL), one squamous cell carcinoma (SCCA), four atypical glandular cells (AGUS), and two adenocarcinomas (ADCA) were reprepped by SurePath™ and antibody to p16INK4A applied at 1:100 dilution using the Dako Envision + System on the Dako Autostainer. Expression of p16INK4A within the nucleus principally and cytoplasm of at least 10–15 cells was considered positive. All initial Papanicolaou‐stained discrepant cases (p16INK4A positivity of NN and RGC cases and lack of reactivity in LSIL, HSIL, and AGUS) were reviewed. Nine of ten (90%) HSIL, one (100%) SCCA, 21/27 (78%) LSIL, and some reactive and inflammatory specimens demonstrated the presence of p16INK4A. Reevaluation of discrepant cases revealed that several were underinterpreted (four NN were LSIL, one RGC was AGUS) or overinterpreted (one LSIL was NN). Following reassessment, false‐positive staining was present in only 1/25 (1.4%) NN. Six of 30 (20%) LSIL lacked p16INK4A positivity. One of 10 (10%) HSIL had no staining. Two of four AGUS did not react with p16INK4A antibody. Both SCCA (1) and ADCA (2) had positive expression. This study confirms the intimate relationship between p16INK4A and HPV cytopathic effect. The p16INK4A immunocytochemical stain can be applied to liquid‐based cervical preparations. This technique offers a more objective approach to deciphering “gray areas” of gynecologic cytopathology. Diagn. Cytopathol. 2002;27:365–370. © 2002 Wiley‐Liss, Inc.
Is high strength concrete more susceptible to explosive spalling than normal strength concrete in fire?
Authors: Ali Faris 
Published: November 2002

AbstractThere is a belief, within the fire research community, that high strength concrete is more susceptible to explosive spalling than normal strength concrete. This impression is based on studying concrete properties and collecting experimental data from different research sources. But there are still doubts about the credibility of this conjecture due to the lack of integrated experimental research, particularly designed to address this issue. This paper represents the outcomes of experimental study involving normal and high strength concrete columns tested under fire. The columns were subjected to a constant load and to different values of axial restraint. The paper attempts to address the question of the susceptibility of normal and high strength concrete to explosive spalling under fire. Copyright © 2002 John Wiley & Sons, Ltd.
T1 efficacy of EVP‐ABD: A potential manganese‐based MR contrast agent for hepatic vascular and tissue phase imaging
Authors: Zuo C.S. , Seoane P. , Lanigan T. , Harnish P. , Prasad P.V. , Storey P. , Li W. , Rofsky N.M. 
Published: November 2002

AbstractPurposeTo evaluate the T1 efficacy of EVP‐ABD, a new manganese (Mn)‐based contrast agent, for vascular and liver tissue enhancement in comparison with currently approved agents.Materials and MethodsTen Yorkshire pigs (body weight, 26 –46 kg) were used for the efficacy evaluation, nine for kinetic T1 evaluation (three each agent) and one for post EVP‐ABD imaging. With a fast imaging scheme to monitor T1 values of blood and liver, 10 μmol/kg EVP‐ABD was injected intravenously and compared with gadopentetate dimeglumine (Magnevist®, GdDTPA) and mangafodipir trisodium (Teslascan®, mangafodipir trisodium) at routine clinical dosages. All were imaged with 3D T1 Gradient Recalled Echo (GRE) sequence (TR/TE/α = 3.8/1.6/25°) prior to and 10 minutes post injection using a 1.5‐T whole‐body scanner. Additional high‐resolution 2D liver images (TR/TE/α = 50/4.6/40°) and arterial phase images of the upper aorta were acquired from the pig for post EVP‐ABD imaging.ResultsAt 10 μmol/kg, EVP‐ABD provided a dramatic decline in blood T1, comparable to 0.1 mmol/kg GdDTPA, followed by a rapid return to blood baseline T1 values. In addition to the blood enhancement phase, EVP‐ABD achieved a 70% reduction in liver T1 within 2 minutes postadministration, with an imaging window of at least 2 hours. A substantially improved signal‐to‐noise ratio (SNR) was observed in both the 2D and 3D liver images postcontrast.ConclusionEVP‐ABD demonstrated peak vascular enhancement similar to GdDTPA and prolonged specific liver enhancement exceeding mangafodipir trisodium. EVP‐ABD has favorable T1 enhancing characteristics with the potential to allow for a comprehensive liver evaluation. J. Magn. Reson. Imaging 2002;16:668–675. © 2002 Wiley‐Liss, Inc.
Serial quantitative diffusion tensor MRI of the premature brain: Development in newborns with and without injury
Authors: Miller Steven P. , Vigneron Daniel B. , Henry Roland G. , Bohland Mary Ann , Ceppi‐Cozzio Camilla , Hoffman Chen , Newton Nancy , Partridge J. Colin , Ferriero Donna M. , Barkovich A. James 
Published: November 2002

AbstractPurposeTo determine the change over time of the apparent diffusion coefficient (ADC) and relative anisotropy of cerebral water in a cohort of premature newborns serially studied near birth and again near term.Materials and MethodsNewborns were classified as normal (N= 11), minimal white matter injury (N= 7), or moderate white matter injury (N= 5).ResultsADC decreased significantly with age in all brain regions in newborns classified as normal and those with minimal white matter injury. ADC increased with age or failed to decline in widespread areas of white matter in newborns with moderate white matter injury. Anisotropy increased with age in all white matter regions in newborns classified as normal. Anisotropy did not increase in frontal white matter in those with minimal white matter injury, and in widespread white matter areas in those with moderate white matter injury.ConclusionThis study demonstrates that serial diffusion tensor magnetic resonance imaging scans of premature newborns can detect differences in white matter maturation in infants with and without white matter injury. J. Magn. Reson. Imaging 2002;16:621–632. © 2002 Wiley‐Liss, Inc.
Pancreatico‐mediastinal fistula with a mediastinal mass lesion demonstrated by MR imaging
Authors: Öksüz Mehmet Ö. , Altehoefer Carsten , Winterer Jan T. , Windfuhr‐Blum Marisa , Kleinschmidt Manuela , von Weizsäcker Fritz , Ochs Andreas , Langer Mathias 
Published: November 2002

AbstractInternal pancreatic fistulas are uncommon but well‐recognized complications of inflammatory pancreatic disease. A case of a pancreatico‐mediastinal fistula with a mediastinal mass lesion in a patient with a documented history of chronic alcohol consumption and previous episodes of acute pancreatitis is described. Since the clinical symptomatology was dominated by pulmonary complaints, magnetic resonance (MR) imaging using a breathhold coronal T2‐weighted sequence with spectral fat saturation was essential in clarifying this difficult and rare pathology. Furthermore, the depiction of a fistulous tract between a mediastinal mass lesion and the retroperitoneum posterior to the pancreas, i.e., a pancreatico‐mediastinal fistula by MR imaging has not been previously reported, to the best of our knowledge. J. Magn. Reson. Imaging 2002;16:746–750. © 2002 Wiley‐Liss, Inc.