bluuebunny/crossref_metadata_2025 huggingface dataset:
FB‐banyans and FB‐delta networks: Fault‐tolerant networks for broadband packet switching
Authors: Chen Wenh‐Shyen E. , Lee Kyungsook Y. , Yao Yow‐Wei , Liu Ming T.
Published: July 2007

Many fast packet switches for the broadband integrated services digital network (BISDN) in the literature are based on banyan networks. Although banyan networks possess nice properties such as a simple control and a low hardware cost, they are unique‐path networks. Since there is a unique path from an input to an output in a banyan network, a single component failure may disrupt services of some nodes connected to such a network. Moreover, banyan networks are also blocking networks; packets can be lost within the networks. To reduce the packet loss, buffered banyan networks can be used.

In an earlier work we have proposed the addition of backward links to otherwise unidirectional banyan networks to create B‐banyans (and B‐delta networks). Backward links not only function as implicit buffers for blocked packets, but also provide multiple paths for each input‐output connection. However, the multiple paths in B‐banyans may not be disjoint.

In this paper, we enhance B‐banyans and B‐delta networks in such a way that the resulting networks can provide disjoint multiple paths for each input‐output pair. The existence of disjoint multiple paths has a significant effect on the network fault‐tolerance. The new networks, called FB‐banyans and FB‐delta networks, arekfault‐tolerant, wherekis the number of backward links per switch and is less than the switch size. They are also robust to more thankfaults, depending on the locations of faults. The maximal fault‐tolerance is achieved whenkis the switch size minus 1. The performance of the new networks is analysed and compared to that of other networks of interest. FB‐banyans and FB‐delta networks can be used as a switch fabric for fast packet switches to provide performance comparable to that of buffered banyan networks and good fault tolerance.
Platinum(II) and Palladium(II) Complexes with N‐Aminoguanidine (Eur. J. Inorg. Chem. 21/2007)
Authors: Aitken David J. , Albinati Alberto , Gautier Arnaud , Husson Henri‐Philippe , Morgant Georges , Nguyen‐Huy Dung , Kozelka Jiří , Lemoine Pascale , Ongeri Sandrine , Rizzato Silvia , Viossat Bernard
Published: July 2007

The cover picture shows shows how aminoguanidine may behave as either a monodentate or bidentate ligand in square‐planar complexes of platinum or palladium. In each case, the coordinating ligands can participate in extensive hydrogen‐bonding networks. Details are discussed in the article by D. J. Aitken, J. Kozelka et al. on p. 3327 ff.
Prediction intervals for growth curve forecasts
Authors: Meade Nigel , Islam Towhidul
Published: July 2007

Since growth curves are often used to produce medium‐ to long‐term forecasts for planning purposes, it is obviously of value to be able to associate an interval with the forecast trend. The problems in producing prediction intervals are well described by Chatfield. The additional problems in this context are the intrinsic non‐linearity of the estimation procedure and the requirement for a prediction region rather than a single interval. The approaches considered are a Taylor expansion of the variance of the forecast values, an examination of the joint density of the parameter estimates, and bootstrapping. The performance of the resultant intervals is examined using simulated data sets. Prediction intervals for real data are produced to demonstrate their practical value.
Forecasting technique familiarity, satisfaction, usage, and application
Authors: Mentzer John T. , Kahn Kenneth B.
Published: July 2007

A ten‐year retrospective study of Mentzer and Cox (1984) was undertaken to answer the question 'Have sales forecasting practices changed over the past ten years?' A mail survey of 207 forecasting executives was employed to investigate this important question. Findings revealed both discrepancies and similarities between today's sales forecasting practices and those of ten years ago. One particular finding indicated greater reliance on and satisfaction with quantitative forecasting techniques today versus ten years ago. Another indicated that forecasting accuracy has not improved over the past ten years, even though the familiarity and usage of various sophisticated sales forecasting techniques have increased. Future research and managerial implications are discussed based on these and other findings.
An assessment of the economic value of non‐linear foreign exchange rate forecasts
Authors: Satchell Steve , Timmermann Allan
Published: July 2007

Recent research suggests that non‐linear methods cannot improve the point forecasts of high‐frequency exchange rates. These studies have been using standard forecasting criteria such as smallest mean squared error (MSE) and smallest mean absolute error (MAE). It is, however, premature to conclude from this evidence that non‐linear forecasts of high‐frequency financial returns are economically or statistically insignificant. We prove a proposition which implies that the standard forecasting criteria are not necessarily particularly suited for assessment of the economic value of predictions of non‐linear processes where the predicted value and the prediction error may not be independently distributed. Adopting a simple non‐linear forecasting procedure to 15 daily exchange rate series we find that although, when compared to simple random walk forecasts, all the non‐linear forecasts give a higher MSE and MAE, when applied in a simple trading strategy these forecasts result in a higher mean return. It is also shown that the ranking of portfolio payoffs based on forecasts from a random walk, and linear and non‐linear models, is closely related to a non‐parametric test of market timing.
Cointegration, error‐correction models, and forecasting using realigned foreign exchange rates
Authors: Joseph Nathan Lael
Published: July 2007

This study employs error‐correction models (ECMs) to forecast foreign exchange (FX) rates where the data‐sampling procedures are consistent with the rules governing the settlement (delivery) of FX contracts in the FX market. The procedure involves thatching (aligning) the forward rate to the 'actual' realized (future) spot rate at the settlement (delivery) date. This approach facilitates the generation of five different sets of sub samples of FX rate series for each currency. For comparative purposes, non‐aligned month‐end rates are also examined. The results indicate that the moments of the realized forecast errors for the same currency are not similar. Further, the ECMs derived are unstable, and their forecasting performance vary. The forecasting performance of the ECMs appear to be affected by the choice of the interval in which the sets of sub samples are observed. These results are attributed to the observed seasonal variation in FX rates.
A re‐evaluation of the quasi‐bayes approach to the linear combination of forecasts
Authors: Faria A. E. , Souza R. C.
Published: July 2007

The subjective forecasts used in decision analysis should, in principle, synthesize all available evidence about the subject in analysis. In this manner, when part of the evidence consists of a variety of forecasting models or expert opinions, Decision Theory requires the decision maker to formulate a combination of these predictors. This work takes into account the Bayesian methodologiesout performanceandquasi‐Bayes, as well as the classical model ofoptimal combination, all applied to the linear combination of petroleum price forecasts, generated by experts from Petrobrás—the Brazilian oil company—for several international markets. It presents a theoretical description of the methodologies followed by a comparative analysis between performances of the best experts' forecasts and combinations. The performances and features of these combinations are also compared.
The decomposition of forecast in seasonal arima models
Authors: Espasa Antoni , Peńa Daniel
Published: July 2007

This paper presents a procedure to break down the forecast function of a seasonal ARIMA model in terms of its permanent and transitory components. Both depend on the initial values at the forecast origin, but their structures are fixed and independent of this origin. The permanent component is an estimate of the long‐run projection of the corresponding economic variable and the transitory element describes the approach towards the permanent one. Within the permanent component a distinction is made between the factors that depend on the initial conditions of the system and those that are deterministic. The procedure is compared to other methods presented in the literature and illustrated in an example.
Predicting nominal variable relationships with multiple response
Authors: Umesh U. N.
Published: July 2007

For forecasting purposes, it is useful to predict the most likely response of an individual to a nominally‐scaled variable using the response to a predictor variable which is also nominally scaled. Traditional statistical approaches are not suitable when respondents provide multiple responses. For practical applications it is desirable to provide a simple measure of prediction that is easy to calculate and understand. Two situations are described where predictions of multiple response are implemented and two indices of predictive association are developed for the situations. These indices provide predictive explanations where none were possible using traditional methods of predictive association. The need to complement these indices with conditional probabilities and log‐linear models is suggested. The evaluation and implications of these indices are discussed.
Judging the probability that the next point in an observed time‐series will be below, or above, a given value
Authors: Bolger Fergus , Harvey Nigel
Published: July 2007

We presented people with trended and untrended time series and asked them to estimate the probability that the next point would be below each of seven different reference values. The true probabilities that the point would be below these values were 0.01, 0.10, 0.25, 0.50, 0.75, 0.90 and 0.99. People overestimated probabilities of less than 0.50 and underestimated those of more than 0.50. Consequently, their subjective probability distributions were flatter than they should have been: people appeared to be under confident in their estimates of where the next point would lie. This bias was greater for the trended series. It was also greater in a second experiment in which people estimated the probability that the next item would be above the reference values. We discuss reasons for these effects and consider their implications for decision making.
Der Wandel der Oasen
Authors: Bürkert Andreas , Schlecht Eva , Häser Jutta
Published: July 2007

Eine hoch entwickelte Oasenlandwirtschaft bot neben dem Fischfang jahrhundertelang die Lebensgrundlage für die sesshafte Bevölkerung des Oman. Am Beispiel von abgelegenen Bergoasen gehen Wissenschaftler der sich wandelnden Wirtschaftsweise in Oasensiedlungen auf den Grund
Das Dach der Welt als Klimasensor
Authors: Schwalb Antje , Steeb Philip , Wrozyna Claudia , Mäusbacher Roland , Daut Gerhard , Wallner Johannes , Kroemer Ernst , Gleixner Gerd , Mügler Ines , Sachse Dirk , Mosbrugger Volker , Schütt Brigitta , Berking Jonas
Published: July 2007

Das Tibetische Hochplateau hat über die letzten fünfzig Millionen Jahre entscheidend das globale Klima beeinflusst. Im Seeschlamm des Nam Co suchen deutsche und chinesische Forscher nach den Spuren folgenreicher Klima‐ und Umweltveränderungen
Gene expression profiling and gene copy‐number changes in malignant mesothelioma cell lines
Authors: Zanazzi Claudia , Hersmus Remko , Veltman Imke M. , Gillis Ad J.M. , van Drunen Ellen , Beverloo H. Berna , Hegmans Joost P.J.J. , Verweij Marielle , Lambrecht Bart N. , Oosterhuis J. Wolter , Looijenga Leendert H.J.
Published: July 2007

Malignant mesothelioma (MM) is an asbestos‐induced tumor that acquires aneuploid DNA content during the tumorigenic process. We used instable MM cell lines as an in vitro model to study the impact of DNA copy‐number changes on gene expression profiling, in the course of their chromosomal redistribution process. Two MM cell lines, PMR‐MM2 (early passages of in vitro culture) and PMR‐MM7 (both early and late passages of in vitro culture), were cytogenetically characterized. Genomic gains and losses were precisely defined using microarray‐based comparative genomic hybridization (array‐CGH), and minimal overlapping analysis led to the identification of the common unbalanced genomic regions. Using the U133Plus 2.0 Affymetrix gene chip array, we analyzed PMR‐MM7 early and late passages for genome‐wide gene expression, and correlated the differentially expressed genes with copy‐number changes. The presence of a high number of genetic imbalances occurring from early to late culture steps reflected the tendency of MM cells toward genomic instability. The selection of specific chromosomal abnormalities observed during subsequent cultures demonstrated the spontaneous evolution of the cancer cells in an in vitro environment. MM cell lines were characterized by copy‐number changes associated with the TP53 apoptotic pathway already present at the first steps of in vitro culture. Prolonged culture led to acquisition of additional chromosomal copy‐number changes associated with dysregulation of genes involved in cell adhesion, regulation of mitotic cell cycle, signal transduction, carbohydrate metabolism, motor activity, glycosaminoglycan biosynthesis, protein binding activity, lipid transport, ATP synthesis, and methyltransferase activity. © 2007 Wiley‐Liss, Inc.
Modelling socioeconomic and health determinants of health‐care use: a semiparametric approach
Authors: Maurer Jürgen
Published: July 2007

This paper suggests bivariate semiparametric index models as a tool for modelling the interplay of socioeconomic and health characteristics in determining health‐care utilisation. These models allow for a fully nonparametric relationship between socioeconomic status, health‐care need and care utilisation. The only parametric restriction imposed is that multiple socioeconomic and health indicators can be aggregated into two distinct indices that measure the broader concepts of socioeconomic status and health‐care need, respectively. We demonstrate the usefulness of this class of models based on an illustrative empirical example. The estimations highlight complex interactions of socioeconomic status and health‐care need in determining care use, which may be difficult to grasp via standard parametric modelling approaches. Copyright © 2007 John Wiley & Sons, Ltd.
Gender differences in smoking behavior
Authors: Bauer Thomas , Göhlmann Silja , Sinning Mathias
Published: July 2007

This paper investigates gender differences in smoking behavior using data from the German Socio‐economic Panel (SOEP). We develop a Blinder–Oaxaca decomposition method for count data models, which allows to isolate the part of the gender differential in the number of cigarettes daily smoked that can be explained by differences in observable characteristics from the part attributable to differences in coefficients. Our results reveal that the major part of the gender smoking differential is attributable to differences in coefficients indicating substantial differences in the smoking behavior between men and women. Copyright © 2007 John Wiley & Sons, Ltd.
Expression profiling reveals genes associated with transendothelial migration of tumor cells: A functional role for αvβ3 integrin
Authors: Bauer Katja , Mierke Claudia , Behrens Jürgen
Published: July 2007

Transendothelial migration is a key step in the extravasation of tumor cells during metastasis formation. Here, we have classified 45 human tumor cell lines derived from various tissues according to their capacity for transendothelial migration in vitro. We could distinguish cell lines showing strong transmigration (TEM+ cell lines) from others that did not transmigrate (TEM− cell lines). By DNA microarray analysis we could cluster TEM+ and TEM− cell lines according to their gene expression pattern and identify genes differentially expressed between the 2 groups. Among these we found the integrin β3 subunit to be highly expressed in TEM+ cell lines as compared to TEM− cell lines. Cell surface localization of αvβ3 integrin receptors was exclusively found in TEM+ cell lines. Transendothelial migration of TEM+ cells but not their adhesion to the endothelial cells, or invasion into collagen gels could be blocked with an antibody against αvβ3 integrin and by RNAi mediated knock‐down of the integrin β3 subunit. These data establishes αvβ3 integrin as one key component of the transendothelial migration process of tumor cells, and as a potential target for anti‐metastatic therapy. Our gene expression analysis of a defined collection of tumor cell lines can be used as a starting point to identify further genes functionally involved in transendothelial migration. © 2007 Wiley‐Liss, Inc.
Modulation of p21‐activated kinase 1 alters the behavior of renal cell carcinoma
Authors: O'Sullivan Gerald C. , Tangney Mark , Casey Garret , Ambrose Monica , Houston Aileen , Barry Orla P.
Published: July 2007

The p21‐activated kinase 1 (Pak1) is a serine/threonine kinase whose activity is regulated by both Rho GTPases and AGC kinase family members. It plays a role in cytoskeletal remodeling and cell motility as well as cell proliferation, angiogenesis, tumorigenesis and metastasis. An involvement of Pak1 in renal cell carcinoma (RCC), which remains highly refractory to chemotherapy and radiotherapy, remains to be investigated. Pak1 expression, phosphorylation and kinase activity were examined in RCC cell lines and human tissue from normal and renal carcinoma. We report increased Pak1 expression and constitutive activity in the membrane and nucleus but not the cytoplasm of resected human RCC. To study a role for Pak1 in RCC, we developed 786‐0 clones that expressed either a kinase‐active Pak1L83,L86 2 different Pak1 dominant negative mutants, Pak1R299 and Pak1L83,L86,R299 or Pak1 siRNA. The expression of Pak1L83,L86 increased 786‐0 proliferation, motility and anchorage independent growth, while the dominant negative mutants and Pak1 siRNA abrogated these effects. In addition, Pak1L83,L86 conferred resistance to 5‐fluorouracil with a 40% ± 10% increase in cell viability. Conversely, Pak1L83,L86,R299, Pak1R299 and Pak1 siRNA conferred sensitivity with a 65.2% ± 5.5%, 69.2% ± 3.3% and 73.0% ± 8.4% loss in viability, respectively. Finally, Pak1 plays a role in renal tumor growth in vivo. Only 33% of mice developed tumors in the Pak1L83,L86,R299 group and no tumors developed from Pak1R299 cell challenge. Together these findings point to Pak1 as an exciting target for therapy of renal cancer, which remains highly refractory to existing treatments. © 2007 Wiley‐Liss, Inc.
Total loss of HLA class I expression on a melanoma cell line after growth in nude mice in absence of autologous antitumor immune response
Authors: Paco Laura , Garcia‐Lora Angel Miguel , Casares Carlos , Cabrera Carmen , Algarra Ignacio , Collado Antonia , Maleno Isabel , Garrido Federico , Lopez‐Nevot Miguel Angel
Published: July 2007

Loss of HLA class I expression on tumor cells is a frequent event as an immune escape mechanism. Seven different altered HLA phenotypes have been defined in tumors. Various molecular mechanisms have been described as responsible for HLA class I loss. HLA class I expression alterations occur successively and unpredictably during tumor progression in vivo and immunoselection has been implicated in this process. We present an experimental xenograft model in which melanoma cell line Ando‐2 injected into athymic nude mice lost total surface HLA class I expression and exhibited HLA class II cell surface expression. A strong down‐regulation of HLA class I expression and de novo HLA class II expression were also found when Ando‐2 melanoma cells were injected into SCID‐Beige mice. These phenomena were reproducible and were only observed in local growth in nude or SCID‐Beige mice and not in vitro after multiple passages. HLA class I surface expression was recovered after IFN‐γ treatment, indicating regulatory defects. The mechanism implicated in loss of HLA class I molecule expression were a down‐regulation of different components of antigen processing machinery and HLA class I heavy chains. These data suggest that HLA class I alterations can also occur in absence of autologous adaptive immune response. This is a good experimental in vivo model to study the relationship between tumor progression and HLA class I alterations. © 2007 Wiley‐Liss, Inc.
Interleukin‐8 modulates growth and invasiveness of estrogen receptor‐negative breast cancer cells
Authors: Yao Chen , Lin Ying , Chua Mei‐Sze , Ye Cai‐Sheng , Bi Jiong , Li Wen , Zhu Yi‐Fan , Wang Shen‐Ming
Published: July 2007

Breast cancer, especially estrogen receptor (ER)‐negative breast cancer, remains hard to treat despite major advances in surgery and adjuvant therapies. The deletion of ER has been consistently associated with tumor progression, recurrence, metastasis and poor prognosis. Among other differences in biological features, ER‐negative breast cancers express high levels of interleukin‐8 (IL‐8), whereas their ER‐positive counterparts do not. IL‐8 is a multi‐functional cytokine with many important biological functions in tumor formation and development. We aimed to study the role(s) of IL‐8 in ER‐negative breast cancer progression by using RNA interference to specifically knockdown IL‐8 expression in ER‐negative breast cancer cell lines MDA‐MB‐231 and MDA‐MB‐468. In vitro, suppression of IL‐8 led to significant reductions in cell invasion (p < 0.001), but had no effects on cell proliferation or cell cycle. In vivo, suppression of IL‐8 significantly reduced the microvessel density (p < 0.05), and markedly reduced neutrophil infiltration into the tumors (p < 0.05). In contrast to in vitro observations, suppression of IL‐8 promoted tumor growth in nude mice (p < 0.05). Our results imply that the complex roles of IL‐8 in the regulation of ER‐negative breast cancer progression may in part be related to its potent chemotactic effects on neutrophils, which in turn mediates many of the biological functions of IL‐8. © 2007 Wiley‐Liss, Inc.
The response of subcutaneous connective tissue to a new endodontic filling material
Authors: Bodrumlu Emre , Muglali Mehtap , Sumer Mahmut , Guvenc Tolga
Published: July 2007

The purpose of this histopathologic study was to assess and compare the subcutaneous connective tissue reaction to a new root canal filling material, Resilon and gutta‐percha. The test materials were directly inserted subcutaneously into the dorsal connective tissue of Wistar albino rats. Histopathological examinations were done at 7, 15, 30, and 60 days after the implantation procedure. The presence of inflammation, predominant cell types, and the thickness of fibrous connective tissue adjacent to each inserted sample were recorded. There were no differences in tissue reaction between Resilon cone material and gutta‐percha cone groups for first three observation periods (p > 0.05). However, there were highly significant differences among observation periods within both groups (7, 15, 30, and 60 days) (p < 0.01). The tissues showed high tolerance to Resilon and gutta‐percha at the 60th day. Resilon may serve as an alternative to gutta‐percha in terms of biocompatibility. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Comparison of cell culture with RT‐PCR for enterovirus detection in stool specimens from patients with acute flaccid paralysis
Authors: Shoja Zabih‐Ollah , Tabatabie Hamideh , Shahmahmoudi Shohreh , Nategh Rakhshandeh
Published: July 2007

Since October 2000, Iran has been declared polio‐free by the World Health Organization (WHO). Despite the fact that poliomyelitis caused by polioviruses has been eliminated from Iran, the number of acute flaccid paralysis (AFP) cases has not been reduced. Therefore, it is of great importance to investigate the other viral agents that may cause AFP (mainly nonpolio enteroviruses, which play a significant role in the etiology of neurological syndromes). Some enteroviruses do not grow in the conventional cell lines that are being used for enterovirus detection. Furthermore, the virus titer is an important factor in the sensitivity of cell culture to detect the virus. The fact that cell culture is a time‐consuming procedure is another reason to find a more practical method for enterovirus detection. Therefore, a more sensitive and rapid method should be used to detect enteroviruses as efficiently as possible in the stool specimens of AFP cases. The aim of this study was to evaluate cell culture and RT‐PCR in enterovirus detection. Findings have shown that RT‐PCR can increase the rate of nonpolio enterovirus detection by up to 10% in comparison with cell culture. Also, the rapid detection of enteroviruses by RT‐PCR can decrease both the unnecessary use of antibiotics and the costs in clinical practice. For this reason, we find that RT‐PCR is a more practical technique for enterovirus detection. J. Clin. Lab. Anal. 21:232–236, 2007. © 2007 Wiley‐Liss, Inc.
P2Y nucleotide receptor signaling through MAPK/ERK is regulated by extracellular matrix: Involvement of β3 integrins
Authors: Kudirka Julie C. , Panupinthu Nattapon , Tesseyman Mark A. , Dixon S. Jeffrey , Bernier Suzanne M.
Published: July 2007

Extracellular matrix influences cell behavior through receptors such as integrins and through transmission of mechanical forces. Nucleotides are released in response to mechanical stimuli and bind to P2 nucleotide receptors. As chondrocytes are subjected to frequent mechanical stimulation within a rich extracellular matrix, they are an excellent model for studying integration of signals induced by matrix and nucleotides. We investigated signaling of G protein‐coupled P2Y receptors to MAPK/ERK and how this is influenced by matrix. Rat articular chondrocytes expressed transcripts for P2Y1, P2Y2, P2Y4, and P2Y6 receptors and responded to extracellular nucleotides by transient elevation of cytosolic calcium and MAPK/ERK phosphorylation. ERK1/2 activation was suppressed by the protein kinase C (PKC) inhibitors bisindolylmaleimide I and rottlerin, and by the phospholipase D inhibitor 1‐butanol. Thus, nucleotides stimulate P2Y receptors to activate ERK1/2 through a mechanism dependent on PKC and phospholipase D. We next examined the involvement of integrins. Both an RGD‐containing pentapeptide and a β3 integrin blocking antibody, but not a β1 integrin blocking antibody, abolished nucleotide‐induced ERK1/2 phosphorylation. Moreover, chondrocytes adhering to fibronectin (which binds to β1 and β3 containing integrins in an RGD‐dependent manner) displayed prolonged ERK1/2 signaling compared to cells grown on type I or II collagen (which bind to β1‐containing integrins in an RGD‐independent manner). In conclusion, P2Y receptor signaling through ERK1/2 is gated selectively by matrix proteins. Thus, nucleotides released in response to mechanical stimulation will have differing effects on cell function due to changes in the composition of the extracellular matrix during development and disease. J. Cell. Physiol. 213: 54–64, 2007. © 2007 Wiley‐Liss, Inc.
Ca2+ signaling differentiation during oocyte maturation
Authors: Machaca Khaled
Published: July 2007

Oocyte maturation is an essential cellular differentiation pathway that prepares the egg for activation at fertilization leading to the initiation of embryogenesis. An integral attribute of oocyte maturation is the remodeling of Ca2+ signaling pathways endowing the egg with the capacity to produce a specialized Ca2+ transient at fertilization that is necessary and sufficient for egg activation. Consequently, mechanistic elucidation of Ca2+ signaling differentiation during oocyte maturation is fundamental to our understanding of egg activation, and offers a glimpse into Ca2+ signaling regulation during the cell cycle. J. Cell. Physiol. 213: 331–340, 2007. © 2007 Wiley‐Liss, Inc.
Soluble receptor inhibits leptin transport
Authors: Tu Hong , Kastin Abba J. , Hsuchou Hung , Pan Weihong
Published: July 2007

Evidence both from mice and cultured cells suggests an important role of soluble leptin receptors in obesity and leptin signaling. However, the direct effects of soluble receptors on leptin uptake by cells are not clear. This study shows that soluble leptin receptors antagonize the permeation of leptin across the mouse blood‐brain barrier by reducing the binding and endocytosis of leptin. This is illustrated by analysis of radioactively labeled and fluorescent‐tagged leptin in normal mice and in cultured cells overexpressing various forms of leptin receptors. Three constructs of soluble leptin receptors were generated in this study: ObRe (805 aa), ObR839, and ObR852. 125I‐leptin was injected intravenously and its influx rate from blood to brain determined by multiple‐time regression analysis. Pre‐incubation with ObR839 caused a significant reduction of leptin influx across the blood‐brain barrier. Endocytosis assays and fluorescent image analysis further showed that ObRe, ObR839, and ObR852 failed to mediate leptin internalization and trafficking within the cells. Instead, these soluble receptors inhibited surface binding and endocytosis of leptin. Thus, we provide novel direct evidence both in vivo and in vitro that soluble receptors of leptin serve as antagonists of the transport of leptin. J. Cell. Physiol. 214: 301–305, 2008. © 2007 Wiley‐Liss, Inc.
Effect of the pineal hormone melatonin on teleost fish phagocyte innate immune responses after in vitro treatment
Authors: Cuesta Alberto , Rodríguez Alejandro , Calderón Ma Victoria , Meseguer José , Esteban Ma Ángeles
Published: July 2007

Although neuroendocrine‐immune system interaction has been shown in teleost fish, no study has evaluated the role of melatonin (Mel) on fish immune response even considering that it is affected by the photoperiod. Gilthead seabream (Sparus aurata L.) and sea bass (Dicentrarchus labrax L.) head‐kidney leucocytes were incubated with Mel (0‐control‐, 20 pM–400 µM) and leucocyte viability and main innate cellular immune parameters were evaluated. Overall, seabream and sea bass head‐kidney leucocytes incubated with low (similar to physiological) doses of Mel unchanged the innate immune response, whereas very high (pharmacological) dosages did. Phagocytosis was not affected by any Mel treatment while the peroxidase activity was significantly inhibited with the highest Mel concentration. In contrast, the sea bass respiratory burst activity was increased in a dose‐dependent manner with 400 nM Mel or higher. Further studies are needed to clarify whether there are interactions between the fish pineal gland, and its hormone Mel, and the fish immune system. J. Exp. Zool. 307A:509–515, 2007. © 2007 Wiley‐Liss, Inc.
Chain Propagation Kinetics on Melt Grafting Reaction
Authors: Shi Qiang , Cai Chuan‐Lun , Zhu Lian‐Chao , Yin Jing‐Hua
Published: July 2007

Graft copolymerization in the molten state is of fundamental importance as a probe of chemical modification and reactive compatibilization. However, few grafting kinetic studies on reactive extrusion have been carried out because of the inherent difficulties, as expected. In this work, we have studied chain propagation kinetics on melt grafting using pre‐irradiated linear low density polyethylene (LLDPE) and three monomers, acrylic acid (AA), methacrylic acid (MAA), and methyl methacrylate (MMA), as the model system. We measured the apparent chain propagation rate coefficients of grafting (kp,g) and homopolymerization (kp,h) at an initial stage for the melt grafting by FT‐IR spectroscopy and electron spin resonance spectroscopy. It was observed that the convective mixing affected the rate coefficients. The magnitude of kp,h and kp,g were in the same order, but kp,h was slightly larger than kp,g. The kp,g of the three grafting systems increased in the order: LLDPE/MMA < LLDPE/MAA < LLDPE/AA. These results are explained in terms of phase separation, solubility, and inherent reactivity of the monomer.

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Dynamic Behavior of the Minority Phase of Photoaddressable Block Copolymers
Authors: Kreger Klaus , Löffler Christina , Walker Roland , Wirth Nadine , Bingemann Dieter , Audorff Hubert , Rössler Ernst A. , Kador Lothar , Schmidt Hans‐Werner
Published: July 2007

We present an analysis of the temperature‐dependent dynamic behavior of the minority phase of photoaddressable block copolymers. Solid‐state 2H NMR investigations are compared with holographic experiments. The samples are diblock copolymers based on polystyrene (PS) and poly(1,2‐butadiene) (PB), where the PB minority segment is functionalized with different deuterated moieties. Solid‐state 2H NMR investigations were performed from 320 to 380 K in order to study the thermal behavior of the minority segment. Holographic experiments on thin films of the block copolymers yielded the photoinduced diffraction efficiency at different temperatures. The comparison of both datasets enables us to identify the glass transition temperature Tg of the minority phase.

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Kinetics of Shear Microphase Orientation and Reorientation in Lamellar Diblock and Triblock Copolymer Melts as Detected via FT‐Rheology and 2D‐SAXS
Authors: Oelschlaeger Claude , Gutmann Jochen S. , Wolkenhauer Markus , Spiess Hans‐Wolfgang , Knoll Konrad , Wilhelm Manfred
Published: July 2007

The microphase orientation/reorientation alignment kinetics behaviour of lamellar PS‐b‐PB diblock and PS‐b‐PB‐b‐PS triblock copolymers under LAOS conditions is studied. By online monitoring the degree of the mechanical nonlinearity during the orientation process, as determined via the higher harmonics in FT rheology [i.e:I3/1(t),ϕ3(t)], and investigation of the orientation distribution by 2D‐SAXS, the kinetics of the microphase alignment for different experimental shear conditions was followed. For di‐ and triblock copolymers, the shear orientation into parallel alignment is possible and the kinetics of orientation is strongly dependent on the strain amplitude.

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Recent Gelation Studies on Irreversible and Reversible Systems with Dynamic Light Scattering and Rheology ‐ A Concise Summary
Authors: Richter Sven
Published: July 2007

“What, then, is truth? A mobile army of metaphors, metonyms, and anthropomorphisms ‐ in short, a sum of human relations which have been enhanced, transposed, and embellished poetically and rhetorically, and which after long use seem firm, canonical, and obligatory to a people: truths are illusions about which one has forgotten that this is what they are; metaphors which are worn out and without sensuous power; coins which have lost their pictures and now matter only as metal, no longer as coins.”

[Friedrich Nietzsche:On Truth and Lie in an Extra‐Moral Sens (1873)]

This contribution is a short summary of the recent achievements of the author in the field of gelation research on irreversible gelling systems based onN‐vinylcaprolactam and on thermoreversible systems (xanthan gum/locust bean gum, and gelatin) mainly based on dynamic light scattering and oscillatory shear rheology. These investigations are discussed in the framework of studies of other authors. It will be pointed out that both methods are well suited to detect the sol‐gel transition, but some expectations that the two different methods can lead to different results will be given, which may be of importance to other systems. In the main focus is the comparison of dynamical critical exponents yielded from the two methods at the sol‐gel transition.

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Raman and Infrared Imaging of Dynamic Polymer Systems
Authors: Koenig Jack L. , Bobiak John P.
Published: July 2007

This work reviews principles of Raman and infrared imaging, as well as applications of the art to understand physiochemical phenomena in polymer systems. Image sequences may be assessed in terms of spatial or spectral changes that occur over time, either within a specific region or across the field of view. As such, the methods have enabled the analysis of diffusion and dissolution processes at polymer interfaces, drug release from polymer matrices, and structural transitions among others. Despite analytical limitations imposed by resolution (spectral or spatial) and sample preparation, Raman and infrared imaging are powerful tools for relating performance attributes to molecular‐level characteristics.

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Weak asymptotics of the spectral shift function
Authors: Bruneau Vincent , Dimassi Mouez
Published: July 2007

We consider the three‐dimensional Schrödinger operator with constant magnetic field of strength b > 0, and with smooth electric potential. The weak asymptotics of the spectral shift function with respect to b ↗ +∞ is studied. First, we fix the distance to the Landau levels, then the distance to Landau levels tends to infinity as b ↗ +∞. In particular we give explicitly the leading terms in the asymptotics and in some case we obtain full asymptotics expansions. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Higher order Teodorescu operators in quaternionic analysis related to the Helmholtz operator
Authors: Ha Vu Thi Ngoc
Published: July 2007

The properties of the Teodorescu integral operator in quaternionic analysis related to the Helmholtz operator and its iteration are investigated. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Oscillatory behavior of linear matrix Hamiltonian systems
Authors: Sun Yuan Gong , Meng Fanwei
Published: July 2007

We establish some new oscillation criteria for the matrix linear Hamiltonian system X ′ = A (t)X + B (t)Y, Y ′ = C (t)X –A *(t)Y by using a new function class X and monotone functionals on a suitable matrix space. In doing so, many existing results are generalized and improved. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Unboundedness of solutions of a class of planar Hamiltonian systems
Authors: Yang Xiaojing , Lo Kueiming
Published: July 2007

In this paper, the unboundedness of solutions for the following planar Hamilton system

Ju ′ = ∇H (u) + h (t)

is discussed, where the function H (u) ∈ C2(R2, R) is positive for u ≠ 0 and is positively (q, p)‐quasihomogeneous of quasi‐degree pq, where p > 1 and $ 1 \over p $ + $ 1 \over q $ = 1, h: S1 → R2 with h ∈ L∞(0, 2π) is 2π ‐periodic and J is the standard symplectic matrix. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Duals of Hardy spaces on homogeneous groups
Authors: Bownik Marcin , Folland Gerald B.
Published: July 2007

Hardy spaces on homogeneous groups were introduced and studied by Folland and Stein [3]. The purpose of this note is to show that duals of Hardy spaces Hp , 0 < p ≤ 1, on homogeneous groups can be identified with Morrey–Campanato spaces. This closes a gap in the original proof of this fact in [3]. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Bourgain property and convex hulls
Authors: Rodríguez José
Published: July 2007

Let (Ω, Σ, μ) be a complete probability space and let X be a Banach space. We consider the following problem: Given a function f: Ω → X for which there is a norming set B ⊂ BX * such that Zf,B = {x * ○ f: x * ∈ B } is uniformly integrable and has the Bourgain property, does it follow that f is Birkhoff integrable? It turns out that this question is equivalent to the following one: Given a pointwise bounded family ℋ︁ ⊂ ℝΩ with the Bourgain property, does its convex hull co(ℋ︁) have the Bourgain property? With the help of an example of D. H. Fremlin, we make clear that both questions have negative answer in general. We prove that a function f: Ω → X is scalarly measurable provided that there is a norming set B ⊂ BX * such that Zf,B has the Bourgain property. As an application we show that the first problem has positive solution in several cases, for instance: (i) when BX * is weak* separable; (ii) under Martin's axiom, for functions defined on [0, 1] with values in a Banach space with density character smaller than the continuum. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impact of adenomatous polyposis coli (APC) tumor supressor gene in human colon cancer cell lines on cell cycle arrest by apigenin
Authors: Chung C.S. , Jiang Y. , Cheng D. , Birt D.F.
Published: July 2007

This research assessed the importance of the adenomatous polyposis coli (APC) tumor suppressor mutation in the ability of apigenin to induce cell cycle arrest using HT29–APC cells, which contain inducible wild‐type APC under the metallothionein promoter. HT29–GAL cells, containing β‐galactosidase (GAL), were included as control. Treatment with apigenin (0, 20, 40, 60, and 80 µM) for 48 h resulted in reduction in the cell number (P < 0.05) concurrent with flow cytometry results showing a dose‐dependent accumulation of cells in the G2/M phase in both HT29–APC and HT29–GAL cells without ZnCl2 treatment. Flow cytometric analysis showed an increase (P < 0.05) in the percentage of cells in G2/M when HT29–APC cells were treated with 80 µM apigenin for 120 h. This increase was not present in HT29–APC cells when treated with both 80 µM apigenin and 100 µM ZnCl2 for 120 h. Western blot analysis verified the induction of APC protein expression in ZnCl2‐treated HT29–APC cells but not in ZnCl2‐treated HT29–GAL cells. Apigenin plus ZnCl2 treatment increased the expression of APC protein in HT29–APC cells by 50 fold above expression observed with ZnCl2 alone. Upon induction of the APC gene with ZnCl2 in HT29–APC cells, the percentage of apoptotic cells increased significantly (P < 0.05) after 120‐h treatment. Additionally, apigenin treatment (80 µM) further increased the percentage of apopototic HT29–APC following ZnCl2 treatment to induce wild‐type APC expression. These results suggest that APC dysfunction may be critical for apigenin to induce cell cycle arrest in human colon cancer cell lines and furthermore, apigenin enhances APC expression and apoptosis in cells with wild‐type APC. © 2007 Wiley‐Liss, Inc.
Inactivation of p27Kip1 promotes chemical mouse liver tumorigenesis in the resistant strain C57BL/6J
Authors: Sun Daqian , Ren Hao , Oertel Michael , Sellers Rani S. , Shafritz David A. , Zhu Liang
Published: July 2007

The biochemical function of p27Kip1 as an inhibitor of cyclin‐dependent kinases is well‐established, but the role of p27 as a tumor suppressor depends on specific cellular contexts. Previous studies using p27 knockout mice on mixed C57BL/6J × 129/Sv strain background did not find a tumor suppressor role of p27 in the liver. An important feature of mouse liver tumorigenesis is strain‐dependent tumor susceptibility. Here, we determined the role of p27 in liver tumorigenesis in C57BL/6J mice, a liver tumor resistant strain, in response to a diethylnitrosamine (DEN) and phenolbarbital (PB) two‐stage carcinogenesis protocol. At 6 mo of age, while livers of DEN–PB treated p27+/+ and p27−/− C57BL/6J mice appeared morphologically normal, p27−/− livers, but not p27+/+ livers, contained readily detectable glucose‐6‐phosphatase (G6Pase)‐deficient foci. At the 9‐mo time point, p27−/− mice developed significantly enhanced liver tumor phenotypes than p27+/+ mice as demonstrated by increased numbers and sizes of liver surface nodules, increased liver‐to‐body weight ratios, and increased numbers of G6Pase‐deficient nodules and histologically diagnosed foci and adenomas in liver sections. Hepatic lesions in p27−/− livers contained more proliferating hepatocytes than lesions in p27+/+ livers, while the numbers of apoptotic cells appeared similar in lesions of both genotypes. Unexpectedly, tumors in p27−/− livers contained only slightly elevated Cdk2 kinase activity compared with normal livers. These results reveal a liver tumor suppressor role of p27 in this resistant mouse strain, and the need to further study the role of Cdk2 kinase in liver tumor promotion by p27 inactivation. © 2007 Wiley‐Liss, Inc.
A superoxide anion generator, pyrogallol, inhibits the growth of HeLa cells via cell cycle arrest and apoptosis
Authors: Kim Sang WooK , Han Yong Whan , Lee Soo Teik , Jeong Hey Jin , Kim Seong Hun , Kim In Hee , Lee Seung Ok , Kim Dae Ghon , Kim Suhn Hee , Kim Sung Zoo , Park Woo Hyun
Published: July 2007

We investigated the in vitro effects of pyrogallol on cell growth, cell cycle regulation, and apoptosis in HeLa cells. Pyrogallol inhibited the growth of HeLa cells with an IC50 of approximately 45 µM. Pyrogallol induced arrest during all phases of the cell cycle and also very efficiently resulted in apoptosis in HeLa cells, as evidenced by flow cytometric detection of sub‐G1 DNA content, annexin V binding assay, and DAPI staining. This apoptotic process was accompanied by the loss of mitochondrial transmembrane potential (ΔΨm), Bcl‐2 decrease, caspase‐3 activation, and PARP cleavage. Pan‐caspase inhibitor (Z‐VAD) could rescue some HeLa cells from pyrogallol‐induced cell death, while caspase‐8 and ‐9 inhibitors unexpectedly enhanced the apoptosis. When we examined the changes of the ROS, H2O2 or O in pyrogallol‐treated cells, H2O2 was slightly increased and O significantly was increased. In addition, we detected a decreased GSH content in pyrogallol‐treated cells. Only pan‐caspase inhibitor showing recovery of GSH depletion and reduced intracellular O level decreased PI staining in pyrogallol‐treated HeLa cells, which indicates dead cells. In summary, we have demonstrated that pyrogallol as a generator of ROS, especially O, potently inhibited the growth of HeLa cells through arrests during all phases of the cell cycle and apoptosis. © 2007 Wiley‐Liss, Inc.
Energy release rate for cracks in finite‐strain elasticity
Authors: Knees Dorothee , Mielke Alexander
Published: July 2007

Griffith's fracture criterion describes in a quasistatic setting whether or not a pre‐existing crack in an elastic body is stationary for given external forces. In terms of the energy release rate (ERR), which is the derivative of the deformation energy of the body with respect to a virtual crack extension, this criterion reads: if the ERR is less than a specific constant, then the crack is stationary, otherwise it will grow.

In this paper, we consider geometrically nonlinear elastic models with polyconvex energy densities and prove that the ERR is well defined. Moreover, without making any assumption on the smoothness of minimizers, we rigorously derive the well‐known Griffith formula and the J‐integral, from which the ERR can be calculated. The proofs are based on a weak convergence result for Eshelby tensors. Copyright © 2007 John Wiley & Sons, Ltd.
Spatial power combining using active microstrip patch antennas
Authors: Hummer Kenneth A. , Chang Kai
Published: July 2007

Active antenna elements have been fabricated using Gunn diodes and microstrip patch antennas. The power outputs from two of these elements have been successfully combined in space. Frequency coherency was achieved by injection locking using either the spatial locking technique or the mutual coupling locking technique.
Experimental investigation of millimeter‐wave GaAs ted oscillators cooled to cryogenic temperatures
Authors: Rydberg Anders , Kollberg Erik
Published: July 2007

The output power and operating (bias) point for 80‐100‐GHz GaAs TED oscillators have been investigated for temperatures between 300 and 40d̀ K. It is shown experimentally that the power can be increased by as much as nearly four times by cooling the oscillator. The thermal design of the oscillator was studied for GaAs and InP TED oscillators.
On the design of an active circulator
Authors: Bahl Inder J.
Published: July 2007

Design of a fully monolithically integrable active circulator without any externally added circuit components is described in this paper. Two different configurations for active circulators using power dividers and Lange couplers are investigated. The circuit using Lange couplers indicates superior performance and is capable of providing O‐dB loss and return loss and isolation better than 16 dB and 23 dB, respectively, over an octave or higher bandwidth.