bluuebunny/crossref_metadata_2025 huggingface dataset:
Bubble formation at orifice in viscoelastic liquids
Authors: Terasaka Koichi , Tsuge Hideki
Published: June 2004

To evaluate the effect of viscoelasticity on bubble formation, four rheological parameters of viscoelastic liquids were defined and measured by a rheometer. The effects of operating conditions and concentration of polyacrylamide aqueous solutions (PAA) as viscoelastic liquids on bubble volume and the growth curve were experimentally measured. A high‐speed video camera showed that the shapes of a bubble growing in vis‐coelastic liquids are not spherical. In this study, a nonspherical bubble formation model was proposed to theoretically estimate the volume, shape and growth curve of bubbles formed from an orifice submerged in viscoelastic liquids which are assumed to follow Maxwell's viscoelastic model. This experimental results in relatively low concentrations of PAA, as well as previous researchers' results, agreed relatively well with the calculated ones by this model.
Experimental study of the influence of the flow rates in SMB chromatography
Authors: Yun Tong , Zhong Guoming , Guiochon Georges
Published: June 2004

A Sorbex‐type SMB separation instrument was operated for the separation of mixtures of 2‐phenyl ethanol and 3‐phenyl‐l‐propanol on a series of eight columns packed with Zorbax C18 bonded silica, using a 60:40 (u/v) solution of methanol and water as the mobile phase. The experiments were carried out with low‐concentration mixtures under linear conditions. The elution profiles of both compounds between any two successive columns of the set under steady‐state conditions were recorded while compositions of the raffinate and extract were measured. The four safety margin factors, βj, were divided into two groups: β1 and β4; β2 and β3 with different influence. Within the framework of the linear, ideal model of chromatography, a range of flow rates enables an SMB to operate successfully by completely separating the feed into its two components. The influence of different flow rates on the performance of the separator was studied by calculations and experiments with excellent agreement between both sets. With a simple optimization strategy, the four flow rates are selected to maximize the production rate or the concentration of extract and raffinate products, or to minimize the desorbent consumption. These optimum conditions are obtained by controlling the locations of concentration profiles inside the SMB. A reliable model for SMB operation allows a rapid and easy selection of the optimum experimental conditions.
Optimal thermodynamic feed conditions for distillation of ideal binary mixtures
Authors: Agrawal Rakesh , Herron D. Michael
Published: June 2004

Optimal thermodynamic feed conditions for distillation of ideal binary mixtures are identified through thermodynamic efficiency analysis of distillation columns. Due to simplifying assumptions, temperatures do not appear explicitly in the final thermodynamic efficiency equations. These equations are found to be functions of only feed composition, the thermodynamic state of the feed, and the relative volatility of the more volatile component A with respect to component B! When a single one‐phase feed, AB, is used, the preferred state of the feed is all liquid when the amount of heavy component B is greater than 50% and is all uapor when the amount of volatile component A is greater than 50%. For a single two‐phase feed, a simple heuristic is presented to adjust the liquid fraction of a given feed to maximize the thermodynamic efficiency of the distillation column. For most binary mixtures, two feeds with the same composition, but one saturated vapor and the other saturated liquid, can improve a distillation column's efficiency substantially. The maximum benefit is obtained for a 50–50 mixture. This two‐feed case is less efficient than the single two‐phase feed case when the relative volatilities exceed certain calculable values.
Coatable splice process in film coating: A fluid mechanical stability problem
Authors: Hackler Mark A. , Brandon Noel C. , Hirshburg Robert I. , Christodoulou Kostas N.
Published: June 2004

In slide coating of photographic films, liquid layers flow down an inclined plane, across a small gap under a pressure differential (vacuum), and onto a fast‐moving substrate. Process interruptions to allow splices of adjoining rolls of substrate to pass through the coater result in significant waste. Coating over splices fails due to air entrainment and/or two free‐surface flow instabilities during the necessary gap widening: (1) standing waves (ribbing) or rupture of the liquid bridge when vacuum is kept high or (2) lateral contraction when vacuum is lowered. The problem of coating over splices is solved here by reducing it to a fluid‐mechanical stability problem. First, air entrainment was eliminated by serrating the splice trailing edge and lateral contraction by prewetting the substrate with liquid streams. Avoiding rupture of the liquid bridge then reduces the problem to finding the vacuum at which the bridge becomes unstable to small disturbances. This “critical” vacuum is found by finite‐element stability analysis of the quasi‐steady 2‐D free‐surface flow to small 2‐D and 3‐D disturbances, direct tracking of critical points, and verification by solving the transient 2‐D skip‐out process. Three modes of failure are predicted if the vacuum is not sufficiently reduced with gap widening. Implementation of a computed vacuum strategy in a production line gave sufficient latitude for coating over imprecise splices.
Electrical properties of conductive adhesives as affected by particle compositions, particle shapes, and oxidizing temperatures of copper powders in a polymer matrix
Authors: Lin Yung‐Sen , Chiu Sheng‐Shiang
Published: June 2004

The effects of particle compositions, particle shapes, and oxidation temperatures on the electrical properties of conductive adhesives have been investigated. Silver‐coated copper powders and uncoated copper powders with spherical and flake‐shaped particles are oxidized at temperatures such as 30, 175, 240, 300°C and 350°C for 2 h and dispersed in an epoxy matrix. The results of this study indicate that the electrical properties of the conductive adhesives are strongly affected by the particle compositions and oxidation temperatures and only slightly affected by the particle shapes. Silver‐coated copper powders show significantly greater oxidation resistance than uncoated copper powders. To understand how silver‐coated copper powders show such oxidation resistance, they are analyzed by the techniques of thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and Auger spectroscopy to observe how metal oxides such as AgO, Cu2O, and CuO affect the electrical properties of the conductive adhesives. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2045–2053, 2004
The complete chirospectroscopic signature of the peptide 310‐helix in aqueous solution
Authors: Toniolo Claudio , Formaggio Fernando , Tognon Sabrina , Broxterman Quirinus B. , Kaptein Bernard , Huang Rong , Setnicka Vladimir , Keiderling Timothy A. , McColl Iain H. , Hecht Lutz , Barron Laurence D.
Published: June 2004

We synthesized by solution methods a water‐soluble, terminally blocked heptapeptide based on five markedly helicogenic, Cα‐tetrasubstituted α‐amino acids Cα‐methyl‐L‐norvalines and two strongly hydrophilic 2‐amino‐3‐[1‐(1,4,7‐triazacyclononane)]‐L‐propanoic acid residues at positions 2 and 5. A Fourier transform infrared absorption and NMR analysis in deuterated chloroform and aqueous solutions of the heptapeptide and two side‐chain protected synthetic precursors confirmed our working hypothesis that all oligomers are folded in the 310‐helical conformation. Based on these findings, we exploited this heptapeptide as a chiral reference compound for detailed electronic CD, vibrational CD, and Raman optical activity characterizations of the 310‐helix in aqueous solution. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Retroinfusion‐supported stenting in high‐risk patients for percutaneous intervention and bypass surgery: Results of the prospective randomized myoprotect I study
Authors: Pohl Tilmann , Giehrl Wolfgang , Reichart Bruno , Kupatt Christian , Raake Philip , Paul Stefan , Reichenspurner Hermann , Steinbeck Gerhard , Boekstegers Peter
Published: June 2004

The objective of this study was to assess event‐free survival and total treatment costs of retroinfusion‐supported stenting in high‐risk patients compared to bypass surgery. An increasing number of patients with main‐stem and main‐stem‐equivalent stenosis are treated by stent implantation, which appears to be safe in the short‐term follow‐up. However, there is a lack of randomized studies comparing conventional bypass surgery with stent implantation, particularly in patients with high risk for both treatments. We here report on the 1‐year results of a prospective randomized single‐center study in patients with symptomatic main‐stem and main‐stem‐equivalent lesions with substantially increased risk for bypass surgery. Patients where randomized to undergo either percutaneous transluminal coronary angioplasty/stent procedure (n = 23) or bypass surgery (n = 21). Patients randomized to stent implantation were supported by selective pressure‐regulated retroinfusion of the anterior cardiac vein during ischemia. Patients of the stent group and the bypass group did not differ in baseline characteristics, including Parsonnet score and quality‐of‐life score. Twenty‐eight‐day mortality and 1‐year mortality rate as well as quality‐of‐life scores were similar in both groups. Event‐free survival after 1 year was higher in the bypass group (71.4% vs. 52.3%; P = 0.02) due to a lower target lesion revascularization rate. With regard to total treatment costs, however, the stent group compared favorably to the bypass group (9,346 ± 807 vs. 26,874 ± 3,985 euro), predominantly as a result of a shorter intensive care and hospital stay. In this first randomized study in high‐risk patients for stent implantation and bypass surgery, patients with retroinfusion‐supported stent implantation had a similar 1‐year outcome and quality of life compared to patients with bypass surgery. Though in the stent group event‐free survival was lower and target lesion revascularization rate was higher, retroinfusion‐supported stent implantation was associated with substantially lower costs and might be considered as an alternative treatment option in this selected group of high‐risk patients. Catheter Cardiovasc Interv 2004;62:323–330. © 2004 Wiley‐Liss, Inc.
Impact of radiation dose on late clinical outcome after intracoronary radiation therapy: Three‐year follow‐up of Long WRIST
Authors: Cheneau Edouard , Canos Daniel , Pinnow Ellen , Ajani Andrew E. , Satler Lowell F. , Pichard Augusto D. , Kent Kenneth M. , Lindsay Joseph , Waksman Ron
Published: June 2004

To determine the safety and efficacy, including the impact, on the late recurrence rate of an incremental γ‐radiation dose from 15 to 18 Gy, we report the 3‐year clinical outcome of Washington Radiation for In‐Stent Restenosis Trial for Long Lesions (Long WRIST). One hundred eighty patients with recurrent in‐stent restenosis (ISR) were enrolled in the Long WRIST series and treated with 192Ir with 1 month of antiplatelet therapy. Between 6 months and 3 years, the need for repeat revascularization was low and similar among the three groups. At 3 years, target lesion revascularization (TLR) and major adverse cardiac events (MACE) were less frequent in the 18 Gy group than in the 15 Gy group (P = 0.12 for TLR, P < 0.05 for MACE) and less frequent in the 15 Gy group as compared to the placebo group (P < 0.05 for TLR and MACE). At 3 years, a higher dose of 18 Gy with 192Ir continues to improve the outcome of patients treated for ISR when compared to patients treated with 15 Gy or placebo. Catheter Cardiovasc Interv 2004;62:318–322. © 2004 Wiley‐Liss, Inc.
Interatrial defect sizing by intracardiac and transesophageal echocardiography compared with fluoroscopic measurements in patients undergoing percutaneous transcatheter closure
Authors: Boccalandro Fernando , Muench Andreas , Salloum Joseph , Awadalla Hany , Carter Catherine , Barasch Eddy , Smalling Richard W.
Published: June 2004

The purpose of this study was to evaluate prospectively the feasibility and accuracy of using echocardiographic measurements by transesophageal and intracardiac echocardiography (TEE and ICE, respectively) for interatrial septal defect sizing during percutaneous transcatheter closure. Forty‐two patients underwent balloon sizing of interatrial septal defects using TEE in 21 of them and ICE in the other half. These measurements were correlated with quantitative fluoroscopic analysis and evaluated for bias and agreement between methods using a Bland‐Altman analysis. Echocardiographic measurements were obtained by ICE and TEE in all patients. An excellent correlation was found between TEE and quantitative fluoroscopy (r = 0.898; P < 0.001) and between ICE and quantitative fluoroscopy (r = 0.876; P < 0.001), with a significant agreement (P < 0.001) and minimal positive bias toward the echocardiographic measurements. Both TEE and ICE are excellent methods of interatrial defect sizing when compared with quantitative fluoroscopic measurements. Catheter Cardiovasc Interv 2004;62:415–420. © 2004 Wiley‐Liss, Inc.
Overlapping vs. one long stenting in long coronary lesions
Authors: Lee Sang Hak , Jang Yangsoo , Oh Sung Jin , Park Kyeong Jin , Moon Yong Sun , Min Ja Won , Yang Joo Young , Jang Gil Jin
Published: June 2004

Intervention of long coronary lesions remains problematic, and optimal treatment strategy is yet to be determined. Despite advancement of stent technology, data are few regarding the efficacy of overlapping stents vs. a single long stent in long coronary lesions. This study was performed to evaluate the results of those strategies for long coronary lesions and to determine the predictors of in‐stent restenosis (ISR). Sixty‐four lesions (> 20 mm) in 64 patients were treated with either one long stent (group 1, n = 32) or two overlapping stents (group 2, n = 32). Overlapping stents were used at tortuous or calcified lesions and at lesions with diameter discrepancy or significant dissection. Immediate results, follow‐up clinical and angiographic outcomes, and predictors of ISR were evaluated. Procedures were successful in all patients in both groups. Clinical and angiographic follow‐ups were performed in 54 (84%) cases and 50 (78%) cases, respectively. During the follow‐up, major adverse cardiac event occurred in 36% of group 1 and 29% of group 2 (P = 0.56). Six‐month ISR rates were 39% in group 1 and 41% in group 2 (P = 0.91). Age (≥ 65 years old) was an independent risk factor of ISR (54% vs. 23%; OR = 4.4; P = 0.04), and distal reference diameter (RD) of less than 2.5 mm tended to predict ISR in multivariate analysis (60% vs. 25%; OR = 3.5; P = 0.06). In conclusion, stent overlapping can be used with outcome similar to that of one long stent in long coronary lesions. The optimal result may be obtained by considering the patient's age and the distal vessel diameter of the lesion. Catheter Cardiovasc Interv 2004; 62:298–302. © 2004 Wiley‐Liss, Inc.
Concomitant coronary and multiple arch vessel stenoses in patients treated with external beam radiation: Pathophysiological basis and endovascular treatment
Authors: Cavendish Jeffrey J. , Berman Brett J. , Schnyder Guido , Kerber Charles , Mahmud Ehtisham , Turi Zoltan G. , Blanchard Daniel , Tsimikas Sotirios
Published: June 2004

External beam radiation‐induced stenoses isolated to the coronary arteries or peripheral vessels have been previously described. We report for the first time the clinical presentation of two patients with concomitant coronary artery and multiple arch vessel disease following external beam radiation of the chest. We review the pathophysiology, discuss the treatment options and describe the percutaneous treatment of coronary, carotid, subclavian, and axillary stenoses related to this rare but likely underdiagnosed disorder. Catheter Cardiovasc Interv 2004;62:385–390. © 2004 Wiley‐Liss, Inc.
Corrosion of tungsten coils after peripheral vascular embolization therapy: Influence on outcome and tungsten load
Authors: Bachthaler Maike , Lenhart Markus , Paetzel Christian , Feuerbach Stefan , Link Johann , Manke Christoph
Published: June 2004

The purpose of this study was to evaluate coil corrosion and the long‐term outcome after peripheral vascular embolization therapy performed with tungsten coils. We studied 14 patients who received tungsten coils on an average of 26 months prior to follow‐up. The protocol included plain radiography and contrast‐enhanced magnetic resonance angiography to investigate corrosion of tungsten coils and recanalization of the embolized vessels. Whole blood, hair, and urine tungsten levels were assayed when available. Corrosion of tungsten coils was detected in 9 of 14 patients by plain radiography. No evidence of recanalization of the embolized vessel and no adverse clinical effects of tungsten resorption were detected. Blood levels of tungsten were elevated in 6 of 14 patients and urine levels of tungsten were elevated in all 12 patients tested. Tungsten coil corrosion and elevated tungsten levels in blood, hair, and urine were found in most patients, although no adverse clinical effects of tungsten resorption were detected. Since the overall effect of high tungsten blood levels remains unclear, its use as an implant should be avoided. Catheter Cardiovasc Interv 2004;62:380–384. © 2004 Wiley‐Liss, Inc.
Crush stenting of bifurcational left subclavian‐vertebral artery stenosis
Authors: Roguin Ariel , Alhaddad Imad A.
Published: June 2004

Left internal mammary artery (LIMA) has the best long‐term patency in patients undergoing coronary artery bypass surgery. Stenosis of the proximal left subclavian artery (SA) may reduce flow to the LIMA, causing myocardial ischemia. We report a novel technique (crush stenting) for the treatment of a complex bifurcational left SA‐vertebral artery (VA) stenosis in the presence of a patent LIMA bypass conduit. This technique limited plaque shifting, restored normal flow to all vessels, including the LIMA, and avoided devastating consequences of VA occlusion. Catheter Cardiovasc Interv 2004;62:393–395. © 2004 Wiley‐Liss, Inc.
Mutational spectra of p53 in geographically localized esophageal squamous cell carcinoma groups in China
Authors: Cao Wei , Chen Xufeng , Dai Huifang , Wang Huizhen , Shen Binghui , Chu David , McAfee Taylor , Zhang Zuo‐Feng
Published: June 2004

BACKGROUND

Esophageal carcinoma is a particularly interesting tumor because of the dramatic difference in its incidence and geographic distribution among populations of similar ethnic origin. Epidemiologic data have suggested that many environmental exposures may be associated with an increased risk of its formation.

METHODS

In this study, 92 samples of esophageal squamous cell carcinoma (ESCC) were collected from patients who resided in 2 geographic areas in China with different incidences of ESCC: Linxian and Zhejiang. Overexpression and mutations of the p53 tumor‐suppressor gene were examined by using immunohistochemistry, single‐strand conformation polymorphism analysis, and direct sequencing.

RESULTS

The rates of point mutation and overexpression of p53 in the ESCC specimens studied were 30.4% (29 of 92 specimens) and 51.1% (47 of 92 specimens), respectively. The overexpression of p53 was associated with tumor metastasis and with 5‐year case fatality. Significant differences were found in the rates of overexpression and mutations in patients with clinical T2 tumors between the specimens from Linxian, which is a high‐incidence geographic area, and the specimens from Zhejiang, which is a low‐incidence area. Furthermore, different mutational spectra were found in the tumor samples from these two geographic areas: In tumor samples from Linxian, the most common substitution mutation was a transversion in exon 5, whereas the most common mutations in tumor samples from Zhejiang were transitions in exon 7.

CONCLUSIONS

The data suggest that the mutation and overexpression of p53 may play important roles in the development of ESCC. The changes in p53 may reflect environmental exposure to the different combinations of mutagenic factors and genetic instability demonstrated by the populations in Linxian and Zhejiang. The overexpression of p53 protein may have significance as a prognostic factor for patients with esophageal carcinoma. Cancer 2004. © 2004 American Cancer Society.
Reactive oxygen species induced by the deletion of peroxiredoxin II (PrxII) increases the number of thymocytes resulting in the enlargement of PrxII‐null thymus
Authors: Moon Eun‐Yi , Han Ying Hao , Lee Dong‐Seok , Han Yong‐Mahn , Yu Dae‐Yeul
Published: June 2004

In the thymus, CD4+ or CD8+ single‐positive (SP) thymocytes develop and mature by positive and negative selection or undergo ‘death by neglect’. CD4+ or CD8+ SP then circulate to other lymphoid tissues. We have investigated the role of reactive oxygen species (ROS) in thymocyte development using peroxiredoxin II (PrxII)‐null mice. The level ofROS in PrxII‐null thymocytes is higher than that in wild‐type mice. Deletion of the PrxII gene leads to enlargement of the thymus in young (9 weeks) and old (64 weeks) mice. The increased number ofthymocytes in PrxII‐null thymus is related to reduced hypodiploid cell formation. For mice on a normal diet, the ratio of SP to double‐positive (DP) thymocytes in thymus of PrxII‐null mice is lower thanthat in wild‐type mice. After food restriction, which leads to increased ROS production, this ratio becomes much higher in PrxII‐null thymus. The amount of apoptosis, induced by food restriction orby the injection of dexamethasone, is consistently lower in PrxII‐null thymocytes than in wild‐type thymocytes. In the presence of low serum concentrations, PrxII‐deleted T cells proliferate more vigorously after stimulation with concanavalin A. Phytohemagglutinin‐ or OKT3‐stimulated proliferation of human peripheral blood mononuclear cells is also higher in the presence of lower serum concentrations. Collectively, the results suggest for the first time that thymocyte maturations and proliferations are regulated by ROS levels induced by the deletion of PrxII gene in vivo.
Molecular, One‐ and Two‐Dimensional Systems Built from Manganese(II) and Phthalate/Diimine Ligands: Syntheses, Crystal Structures and Magnetic Properties
Authors: Ma Chengbing , Wang Wenguo , Zhang Xiaofeng , Chen Changneng , Liu Qiutian , Zhu Hongping , Liao Daizheng , Li Licun
Published: June 2004

Several new MnII compounds, [Mn2(Hphth)2(phen)4](Hphth)2·2H2O (1; H2phth = phthalic acid, phen = 1,10‐phenanthroline), [Mn2(Hphth)2(phen)4](ClO4)2·2H2O (2), [Mn4(phth)4(phen)4(H2O)4]·2EtOH (3), {[Mn4(phth)2(phen)8](PF6)4}2 (4), [Mn4(phth)2(bipy)8](ClO4)4·2EtOH (5; bipy = 2,2′‐bipyridine), [Mn(phth)(bipy)(H2O)2]n (6), and [Mn(phth)(pyz)(H2O)2]n (7; pyz = pyrazine), have been synthesized by treatment of the appropriate Mn2+ salt and H2phth with different diimine ligands. They were characterized by X‐ray diffraction and show a variety of nuclearities, ranging from dinuclear (1 and 2) to tetranuclear (3−5), and dimensionalities, ranging from a 1D chain (6) to a 2D layer network (7), in which the phthalates act as primary bridging ligands coordinating to Mn atoms through their carboxylate groups in various bonding modes. Variable‐temperature magnetic susceptibility measurements reveal weak anti‐ferromagnetic coupling interactions in 1, 3, 4 and 6. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Body Image Self‐evaluation Colouring Lens: comparing the ornamental and instrumental views of adolescent girls with eating disorders
Authors: Gusella Joanne , Clark Sharon , van Roosmalen Erica
Published: June 2004

A new visual measure of body image, the Body Image Self‐evaluation Colouring Lens (BISCL), was used to examine how 22 girls with diagnosed eating disorders evaluated their bodies. Results revealed that the percent of negative body evaluation was significantly higher when girls evaluated their body form as compared to their body function. Girls expressed new insights when comparing their relatively positive evaluation of their body functioning to their generally negative view of their body appearance. They expressed dissatisfaction with body parts that did not conform to their current cultural ideals. The BISCL was correlated in a predictable manner with standardized measures of body dissatisfaction. The promising applications of the BISCL as a clinical and research tool are discussed. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
A longitudinal study of the relationship between body image, self‐esteem and dieting among 15–21 year olds in Norway
Authors: Friestad Christine , Rise Jostein
Published: June 2004

Purpose

The study investigates the predictive value of body image, self‐esteem and gender for adolescent dieting at ages 15, 18 and 21 and whether adolescents' self‐esteem moderates the relationship between body image and dieting.

Method

Data stem from the Norwegian Longitudinal Health Behaviour Study (NLHB study): Adult by the Year 2000 (‘Voksen i år 2000’). The NLHB study is a 10‐year prospective cohort study based on self‐completed questionnaires investigating health behaviour and lifestyle patterns among Norwegian adolescents. This paper presents data from Wave II (1992), Wave IV (1995) and Wave VI (1998), thus covering the ages 15, 18 and 21. Analyses are based on the 487 respondents participating at all three timepoints.

Results

At all ages included, 25% of the girls reported they had dieted several times over the past year, while the corresponding figure for boys was 5%. Among boys, self‐esteem and body image contributed to the same extent in the prediction of dieting, while only body image proved a significant predictor among girls, increasing in importance over time. Interaction between self‐esteem and body image was present among young boys (ages 15 and 18) only.

Conclusions

Self‐esteem and body image play quite different roles in the prediction of dieting among girls and boys. The difference is not only related to strength of association between the variables, but, more importantly, to qualitatively different underlying processes. Copyright © 2004 John Wiley & Sons, Ltd and Eating Disorders Association.
Brain–behavior correlation in children depends on the neurocognitive network
Authors: Booth James R. , Burman Douglas D. , Meyer Joel R. , Trommer Barbara L. , Davenport Nicholas D. , Parrish Todd B. , Gitelman Darren R. , Mesulam M. Marsel
Published: June 2004

We examined brain–behavior correlations in 12 children (age range 9.3 to 11.7 years) during a selective attention task that required the visual search of a conjunction of features and during a response inhibition task that required the inhibition of a pre‐potent response during “no‐go” blocks. We found that the association between performance in these tasks and brain activation as measured by functional magnetic resonance imaging (fMRI) depended on the neurocognitive network. Specifically, better performance during the no‐go task was associated with greater activation in the response inhibition network including the prefrontal cortex and basal ganglia. In contrast, better performance during the visual search task was associated with less activation in the selective attention network including superior parietal lobule and lateral premotor cortex. These results show that the relation of performance to the magnitude of neural activation is complex and may display differential relationships based on the cognitive domain, anatomical region, and perhaps also developmental stage. Hum Brain Mapping 23:99–108, 2004. © 2004 Wiley‐Liss, Inc.
Enhancement of the p27Kip1‐mediated antiproliferative effect of trastuzumab (Herceptin) on HER2‐overexpressing tumor cells
Authors: Marches Radu , Uhr Jonathan W.
Published: June 2004

The oncogenic activity of the overexpressed HER2 tyrosine kinase receptor requires its localization in the plasma membrane. The antitumor effect of anti‐HER2 antibodies (Abs) is mainly dependent on receptor downregulation and comprises p27Kip1‐mediated G1 cell cycle arrest. However, one major limitation of anti‐HER2 therapy is the reversibility of tumor growth inhibition after discontinuation of treatment caused by the mitogenic signaling associated with cell surface receptor re‐expression. We found that the level of p27Kip1 upregulation, inhibition of Cdk2 activity and magnitude of G1 arrest induced by the humanized Ab trastuzumab (Herceptin, HCT) on BT474 and SKBr3 HER2‐overexpressing breast cancer cells correlates with the level of cell surface receptor. Thus, continuous exposure of cells to HCT for 72 hr results in downregulation of the cell surface receptor and a concurrent increase in the level of p27Kip1 protein. Discontinuation of Ab exposure after the first 8 hr results in failure to upregulate p27Kip1 and arrest of cell cycle progression. We show that the lysosomotropic amine chloroquine (CQ) augments receptor internalization in HER2‐overexpressing cells either pretreated or continuously treated with HCT and leads to an increased and sustained inhibitory effect. The enhanced CQ‐dependent loss of functional HER2 from the cell surface resulted in sustained inactivation of the serine/threonine kinase Akt, upregulation of p27Kip1 protein and inhibition of cyclin E/Cdk2 activity. Potentiation of the inhibitory effect of HCT by CQ was directly related to loss of HER2 from the plasma membrane since prevention of Ab‐mediated receptor endocytosis by engagement of the receptor with immobilized HCT abrogated the effect of CQ. © 2004 Wiley‐Liss, Inc.
Dissecting progressive stages of 5‐fluorouracil resistance in vitro using RNA expression profiling
Authors: Schmidt Wolfgang M. , Kalipciyan Maria , Dornstauder Eva , Rizovski Blanka , Steger Guenther G. , Sedivy Roland , Mueller Manfred W. , Mader Robert M.
Published: June 2004

Resistance to anticancer drugs such as the widely used antimetabolite 5‐fluorouracil (FU) is one of the most important obstacles to cancer chemotherapy. Using GeneChip arrays, we compared the expression profile of different stages of FU resistance in colon cancer cells after in vitro selection of low‐, intermediate‐ and high‐resistance phenotypes. Drug resistance was associated with significant changes in expression of 330 genes, mainly during early or intermediate stage. Functional annotation revealed a majority of genes involved in signal transduction, cell adhesion and cytoskeleton with subsequent alterations in apoptotic response, cell cycle control, drug transport, fluoropyrimidine metabolism and DNA repair. A set of 33 genes distinguished all resistant subclones from sensitive progenitor cells. In the early stage, downregulation of collagens and keratins, together with upregulation of profilin 2 and ICAM‐2, suggested cytoskeletal changes and cell adhesion remodeling. Interestingly, 6 members of the S100 calcium‐binding protein family were suppressed. Acquisition of the intermediate‐resistance phenotype included upregulation of the well‐known drug resistance gene ABCC6 (ATP‐binding cassette subfamily C member 6). The very small number of genes affected during transition to high resistance included the primary FU target thymidylate synthase. Although limited to an in vitro model, our data suggest that resistance to FU cannot be explained by known mechanisms alone and substantially involves a wide molecular repertoire. This study emphasizes the understanding of resistance as a time‐depending process: the cell is particularly challenged at the beginning of this process, while acquisition of the high‐resistance phenotype seems to be less demanding. © 2004 Wiley‐Liss, Inc.
Green tea consumption enhances survival of epithelial ovarian cancer
Authors: Zhang Min , Lee Andy H. , Binns Colin W. , Xie Xing
Published: June 2004

Our study investigates whether tea consumption can enhance the survival of patients with epithelial ovarian cancer, a prospective cohort study was conducted in Hangzhou, China. The cohort comprised 254 patients recruited during 1999–2000 with histopathologically confirmed epithelial ovarian cancer and was followed up for a minimum of 3 years. Two hundred forty four (96.1%) of the cohort or their close relatives were traced. The variables examined included their survival time and the frequency and quantity of tea consumed post‐diagnosis. The actual number of deaths was obtained and Cox proportional hazards models were used to obtain hazard ratios and associated 95% confidence intervals (CI), adjusting for age at diagnosis, locality, BMI, parity, FIGO stage, histologic grade of differentiation, cytology of ascites, residual tumour and chemotherapeutic status. The survival experience was different between tea drinkers and non‐drinkers (p < 0.001). There were 81 (77.9%) of 104 tea‐drinkers who survived to the time of interview, compared to only 67 women (47.9%) still alive among the 140 non‐drinkers. Compared to non‐drinkers, the adjusted hazard ratios were 0.55 (95% CI = 0.34–0.90) for tea‐drinkers, 0.43 (95% CI = 0.20–0.92) for consuming at least 1 cup of green tea/day, 0.44 (95% CI = 0.22–0.90) for brewing 1 batch or more of green tea/day, 0.40 (95% CI = 0.18–0.90) for consuming more than 500 g of dried tea leaves/year, and 0.38 (95% CI = 0.15–0.97) for consuming at least 2 g of dried tea leaves/batch. The corresponding dose‐response relationships were significant (p < 0.05). We conclude that increasing the consumption of green tea post‐diagnosis may enhance epithelial ovarian cancer survival. © 2004 Wiley‐Liss, Inc.
Novel mechanism of tumorigenesis: Increased transforming growth factor‐β1 suppresses the expression of connexin 43 in BALB/cJ mice after implantation of poly‐L‐lactic acid
Authors: Ahmed Saifuddin , Tsuchiya Toshie
Published: June 2004

Poly‐L‐lactic acid (PLLA) is a widely used promising material for surgical implants such as tissue‐engineered scaffolds. In this study, we aimed to determine the in vivo effect of PLLA plates on the cellular function of subcutaneous tissue in the two mouse strains, BALB/cJ and SJL/J, higher and lower tumorigenic strains, respectively. Gap‐junctional intercellular communication (GJIC) and the expression of connexin 43 (Cx43) protein were significantly suppressed, whereas the secretion of transforming growth factor‐β1 (TGF‐β1) level was significantly increased in PLLA‐implanted BALB/cJ mice compared with BALB/cJ controls. However, no significant difference in TGF‐β1 secretion was observed between the SJL/J‐implanted and SJL/J control mice. We found for the first time that a significant difference was observed between the two strains; thus, the PLLA increased the secretion of TGF‐β1 and suppressed the mRNA expression of Cx43 at the earlier stage after implantation into the higher‐tumorigenic strain, BALB/cJ mice. This novel mechanism might have a vital role in the inhibition of GJIC and promote the tumorigenesis in BALB/cJ mice. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 70A: 335–340, 2004
Primary mouse embryonic fibroblasts: A model of mesenchymal cartilage formation
Authors: Lengner Christopher J. , Lepper Christoph , van Wijnen Andre J. , Stein Janet L. , Stein Gary S. , Lian Jane B.
Published: June 2004

Cartilage formation is an intricate process that requires temporal and spatial organization of regulatory factors in order for a mesenchymal progenitor cell to differentiate through the distinct stages of chondrogenesis. Gene function during this process has best been studied by analysis of in vivo cartilage formation in genetically altered mouse models. Mouse embryonic fibroblasts (MEFs) isolated from such mouse models have been widely used for the study of growth control and DNA damage response. Here, we address the potential of MEFs to undergo chondrogenic differentiation. We demonstrate for the first time that MEFs can enter and complete the program of chondrogenic differentiation ex vivo, from undifferentiated progenitor cells to mature, hypertrophic chondrocytes. We show that chondrogenic differentiation can be induced by cell–cell contact or BMP‐2 treatment, while in combination, these conditions synergistically enhance chondrocyte differentiation resulting in the formation of 3‐dimensional (3‐D) cartilaginous tissue ex vivo. Temporal expression profiles of pro‐chondrogenic transcription factors Bapx1 and Sox9 and cartilaginous extracellular matrix (ECM) proteins Collagen Type II and X (Coll II and Coll X) demonstrate that the in vivo progression of chondrocyte maturation is recapitulated in the MEF model system. Our findings establish the MEF as a powerful tool for the generation of cartilaginous tissue ex vivo and for the study of gene function during chondrogenesis. © 2004 Wiley‐Liss, Inc.
Quasistatic and dynamic problems in viscoplasticity theory—non‐linearities with power growth
Authors: Pompe Waldemar
Published: June 2004

We find a common abstract formulation of the quasistatic and dynamic problems from viscoplasticity theory. Based on this formulation we show existence and uniqueness of the solution to this abstract problem by choosing appropriate spaces and by reducing the problem to an evolution equation, which can be treated by the general theory of monotone operators in Hilbert space. Our proof is valid for non‐linearities in the constitutive equation with power law growth. Copyright © 2004 John Wiley & Sons, Ltd.
A three dimensional embedded beam element for reinforced geomaterials
Authors: Sadek Machhour , Shahrour Isam
Published: June 2004

This paper presents the formulation and verification of a 3D embedded beam element, which is intended for numerical modelling of three dimensional problems concerned by reinforced geomaterials. This element permits analysis of reinforced geomaterial structures with simplified meshes, that do not need to account for reinforcement orientation. The paper is composed of four sections. Section 1 discusses the need for the development of a particular beam element for soil reinforcement, which can be easily used in practical applications. Section 2 describes the mathematical formulation of this element, while Section 3 deals with its verification on various examples. Section 4 illustrates an application of this element by analysing the behaviour of a group of micropiles containing inclined elements and subjected to lateral loading. Copyright © 2004 John Wiley & Sons, Ltd.
Deterministic and stochastic scheduling with teamwork tasks
Authors: Cai Xiaoqiang , Zhou Xian
Published: June 2004

We study a class of new scheduling problems which involve types of teamwork tasks. Each teamwork task consists of several components, and requires a team of processors to complete, with each team member to process a particular component of the task. Once the processor completes its work on the task, it will be available immediately to work on the next task regardless of whether the other components of the last task have been completed or not. Thus, the processors in a team neither have to start, nor have to finish, at the same time as they process a task. A task is completed only when all of its components have been processed. The problem is to find an optimal schedule to process all tasks, under a given objective measure. We consider both deterministic and stochastic models. For the deterministic model, we find that the optimal schedule exhibits the pattern that all processors must adopt the same sequence to process the tasks, even under a general objective function GC = F(f1(C1), f2(C2), … , fn(Cn)), where fi(Ci) is a general, nondecreasing function of the completion time Ci of task i. We show that the optimal sequence to minimize the maximum cost MC = max fi(Ci) can be derived by a simple rule if there exists an order f1(t) ≤ … ≤ fn(t) for all t between the functions {fi(t)}. We further show that the optimal sequence to minimize the total cost TC = ∑ fi(Ci) can be constructed by a dynamic programming algorithm. For the stochastic model, we study three optimization criteria: (A) almost sure minimization; (B) stochastic ordering; and (C) expected cost minimization. For criterion (A), we show that the results for the corresponding deterministic model can be easily generalized. However, stochastic problems with criteria (B) and (C) become quite difficult. Conditions under which the optimal solutions can be found for these two criteria are derived. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004
Stochastic scheduling subject to machine breakdowns: The preemptive‐repeat model with discounted reward and other criteria
Authors: Cai Xiaoqiang , Sun Xiaoqian , Zhou Xian
Published: June 2004

We consider the problem of scheduling a set of jobs on a single machine subject to random breakdowns. We focus on the preemptive‐repeat model, which addresses the situation where, if a machine breaks down during the processing of a job, the work done on the job prior to the breakdown is lost and the job will have to be started from the beginning again when the machine resumes its work. We allow that (i) the uptimes and downtimes of the machine follow general probability distributions, (ii) the breakdown process of the machine depends upon the job being processed, (iii) the processing times of the jobs are random variables following arbitrary distributions, and (iv) after a breakdown, the processing time of a job may either remain a same but unknown amount, or be resampled according to its probability distribution. We first derive the optimal policy for a class of problems under the criterion to maximize the expected discounted reward earned from completing all jobs. The result is then applied to further obtain the optimal policies for other due date‐related criteria. We also discuss a method to compute the moments and probability distributions of job completion times by using their Laplace transforms, which can convert a general stochastic scheduling problem to its deterministic equivalent. The weighted squared flowtime problem and the maintenance checkup and repair problem are analyzed as applications. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004
Wavefront reduction using graphs, neural networks and genetic algorithm
Authors: Kaveh A. , Bondarabady H. A. Rahimi
Published: June 2004

This paper presents an algorithm for nodal numbering in order to obtain a small wavefront. Element clique graphs are employed as the mathematical models of finite element meshes. A priority function containing five vectors is used, which can be viewed as a generalization of Sloan's function. These vectors represent different connectivity properties of the graph models. Unlike Sloan's algorithm, which uses two fixed coefficients, here, five coefficients are employed, based on an evaluation by artificial neural networks. The networks weights are obtained using a simple genetic algorithm. Examples are included to illustrate the performance of the present hybrid method. Copyright © 2004 John Wiley & Sons, Ltd.
Radical copolymerization of maleimide with ethyl α‐ethylacrylate and α‐ethylacrylic acid via RAFT
Authors: Ren Yong , Zhu Zhongliang , Huang Junlian
Published: June 2004

The copolymerization of maleimide (MI) with α‐ethylacrylic acid (EAA) and with ethyl α‐ethylacrylate (EEA) in the presence of 2‐phenylprop‐2‐yl dithiobenzoate (PPDB) was investigated. The copolymerization of MI and EAA was difficult to conduct with the reversible addition–fragmentation chain transfer (RAFT) mechanism because reinitiation of expelled radicals by fragmentation chain transfer was inhibited by the association of EAA in polar solvent and the strong interaction of the imino of MI with the carboxyl of EAA between the propagation chains. When the carboxylic group of EAA was esterified, then the copolymerization went well via RAFT, and alternating copolymers with controlled molecular weight were obtained. Combining by electron spin resonance showed a different result. It was found that before 30% of the comonomer conversion had occurred, the copolymer poly(EEA‐co‐MI) showed increasing molecular weight with the conversion and a rather narrow molecular weight distribution; then the molecular weight of the copolymer began to retard. This phenomenon of retardation was aggravated at high temperature. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3828–3835, 2004
Permeability of N2, Ar, He, O2, and CO2 through as‐extruded amorphous and biaxially oriented polyester films: Dependence on chain mobility
Authors: McGonigle E.‐A. , Liggat J. J. , Pethrick R. A. , Jenkins S. D. , Daly J. H. , Hayward D.
Published: June 2004

For as‐extruded amorphous and biaxially orientated polyester films based on poly(ethylene terephthalate), poly(ethylene naphthalate), and copolymers containing poly(ethylene terephthalate) and poly(ethylene naphthalate) moieties, permeability, diffusion, and solubility coefficients are interpreted in terms of chain mobility. The influence of polymer morphology is determined by comparison of the data for as‐extruded amorphous sheets and materials produced with different biaxial draw ratios. The crystallinities of the samples were assessed using differential scanning calorimetry and density measurements. Changes in mobility at a molecular level were investigated using dielectric spectroscopy and dynamic mechanical thermal analysis. The study, in conjunction with our earlier work, leads to the conclusion that the key to understanding differences in gas transport is the difference in local chain motions rather than in free volume. This was illustrated by the permeability results for He, Ar, N2, and O2 in the range of polyesters. However, the permeability of CO2 was found to require alternative explanations because of polymer–penetrant interactions. For biaxially oriented samples, the differences in diffusivity are not only due to differences in local chain motions, but also additional constraints resulting from the increased crystallinity and chain rigidity—which also act to hinder segmental mobility. The effectiveness of the reduction in permeability in the biaxially oriented films is consequently determined by the ability of the polymer chains to effectively align and form crystalline structures. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2916–2929, 2004
Statistical evaluation of Lower Flammability Distance (LFD) using four hazardous release models
Authors: Kumar Ashok , Luo Jie , Bennett Gary F.
Published: June 2004

Using four hazardous dispersion models, the ability to predict Lower Flammability Distance (LFD), the distance from a release through which the released gas is present in concentration below flammable range, has been evaluated using a set of large‐scale propane release field experiment data. The four models evaluated were the DEGADIS model, the SLAB model, the OME Simple Gas model and the OME Heavy Gas model (1983). The observed LFDs were compared with the predicted LFDs for three atmospheric conditions. The complete data set was broken into two parts: (1) the cyclone type releases (representing instantaneous release situations) and (2) the nozzle type releases (representing horizontal jet releases). A procedure based on the USEPA guidelines on air quality models was followed to evaluate the models.

The complex models (DEGADIS and SLAB models) appear unreasonably weak in predicting LFD's compared with the relatively simple Gaussian model used in the OME Simple Gas model for instantaneous releases. The OME simple gas model is significantly better than the DEGADIS and SLAB models for cyclone type (instantaneous) releases under unstable and neutral atmospheric conditions; and the DEGASIS model is significantly better than the SLAB model for nozzle type (horizontal jet) releases under stable atmospheric conditions. Since the size of the data set is not large enough (n = 20 for cyclone type release and n = 18 for nozzle type release), it is difficult to show 95% significant differences between models.