bluuebunny/crossref_metadata_2025 huggingface dataset:
Gradient‐based parameter optimization for systems containing discrete‐valued functions
Authors: Wilson Edward , Rock Stephen M.
Published: October 2002

Gradient‐based parameter optimization is commonly used for training neural networks and optimizing the performance of other complex systems that only contain continuously differentiable functions. However, there is a large class of important parameter optimization problems involving systems containing discrete‐valued functions that do not permit the direct use of gradient‐based methods. Examples include optimization of control systems containing discrete‐level actuators such as on/off devices, systems with discrete‐valued inputs and outputs, discrete‐decision‐making systems (accept/reject), and neural networks built with signums (also known as hard‐limiters or Heaviside step functions) rather than sigmoids. Even if most of the system is continuously differentiable, the presence of one or more discrete‐valued functions will not allow gradient‐based optimization to be used directly. A new algorithm, ‘noisy backpropagation,’ is developed here, as an extension of backpropagation, which solves this problem and extends gradient‐based parameter optimization to permit application to systems containing discrete‐valued functions. Moreover, the modification to backpropagation is small, requiring only (1) replacement of the discrete‐valued functions with continuously differentiable approximations, and (2) injection of noise into the smooth approximating function on the forward sweep during training. Noise injection is the key to reducing the round‐off error created when the discrete‐valued functions are replaced after training. This generic approach is applicable whenever gradient‐based parameter optimization is used with systems containing discrete‐valued functions; it is not limited to training neural networks. The examples in this paper demonstrate the use of noisy backpropagation in training two different multi‐layer signum networks and in training a neural network for a control problem involving on‐off actuators. This final example includes implementation on a laboratory model of a ‘free‐flying space robot’ to validate the realizability and practical utility of the method. Copyright © 2002 John Wiley & Sons, Ltd.
Dynamics of discharge, sediment transport, heavy metal pollution and Sábalo (Prochilodus lineatus) catches in the lower Pilcomayo river (Bolivia)
Authors: Smolders A. J. P. , Guerrero Hiza M. A. , van der Velde G. , Roelofs J. G. M.
Published: October 2002

The Pilcomayo river is one of the few intact natural river systems left on the South American continent. The high, largely natural, sediment loads of the river have led to the development of an alluvial fan system, which is still active. The river is currently retracting due to siltation of its bed, and in the near future the river is likely to abruptly change its course. There is a large difference in discharge between the wet and dry seasons. Pollution of the transported sediments by heavy metals from the mining district of Potosí is largely prevented by dilution of the toxic mining sludges with clean sediments derived from natural erosion processes. The Sábalo (Prochilodus lineatus) is a migrating fish which is very important for commercial fishing. The Sábalo grows up in the floodplains in the lower reaches of the river and starts its upstream migration at the end of the rainy season to spawn in the Andean foothill at the beginning of the next rainy season. Pollution does not seem to affect fish catches. Sábalo catches in a given year, however, do appear to depend strongly on the mean discharge in the three preceding years. Annual discharge is strongly influenced by the El Niño–Southern Oscillation (ENSO) phenomenon. Copyright © 2002 John Wiley & Sons, Ltd.
Iterative demodulation and decoding of high‐order CPM signals in Rician fading channels
Authors: Xu Yingjiu , Geraniotis Evaggelos
Published: October 2002

Space communications require high data rate information transmission at low bit error rate (BER). In this paper, we present a pilot symbol‐assisted, iterative demodulation and decoding system for high‐order continuous phase modulated (CPM) signals. We consider CPM signals because they are especially suitable for space communications due to their high spectral efficiency and constant envelope property.

Coherent demodulation is adopted because of its superior BER performance over non‐coherent demodulation like differential detection. To track the time‐varying channel state information (CSI) caused by the Doppler effect in space communications, pilot symbols are inserted periodically in the data stream to serve as references for channel estimation. Due to the inherent memory in continuous phase modulation, those pilot symbols are set to be data dependent so that the CPM phase trellis can be forced to some pre‐defined reference state at certain time epochs. In addition, pilot symbols are used as parity check symbols in demodulating each pilot frame to help reduce decoding errors. Powerful forward error correcting codes (convolutional codes) are then combined with the phase trellis of the CPM signal to form a structure similar to serial concatenated convolutional codes so that the BER performance can be significantly improved by applying iterative processing. Compared with other joint detection and decoding systems, the proposed system has high power‐bandwidth efficiency and low computational complexity by using pilot symbols to separate channel estimation from demodulation, which is even more significant in high‐order modulation.

To further improve the receiver performance, information is exchanged between the CPM demodulator, the convolutional decoder, and the channel estimator. First, the channel estimator uses the information from CPM demodulator to construct an estimate of the phase trajectory of the transmitted signal and filters all received samples on this estimated phase trajectory to obtain a more accurate estimation of the CSI. Then the CPM demodulator combines this newly estimated CSI with the extrinsic information from the convolutional decoder to generate more reliable soft decisions, which is to be used as input to the convolutional decoder. This process can be carried out iteratively to improve the BER performance. Although there may be some errors in reconstructing the phase trajectory which will cause an increase in channel estimation errors, the number of errors will decrease at high signal‐to‐noise ratio and the accuracy of the estimated CSI will improve due to the increased sampling rate.

At last, it should be pointed out that although the proposed system is designed for CPM signals, it applies in general to other signals modulated with memory such as differential phase‐shift keying. We have already obtained similar results for differential QPSK in Rician fading channels. Copyright © 2002 John Wiley & Sons, Ltd.
Symbol synchronization properties of CCSDS turbo codes
Authors: Calzolari Gian Paolo , Chiaraluce Franco , Garello Roberto , Vassallo Enrico
Published: October 2002

The Consultative Committee for Space Data Systems (CCSDS) standards establish a common framework for space telemetry, command and tracking, and covers many applications like deep space and near‐Earth missions, Earth exploration, tracking and data relay satellites. In this paper, we present a study on the symbol synchronization properties of the turbo code scheme recently adopted as one of the channel coding options for CCSDS telemetry recommendations. An extensive analysis is presented for transition/symbol probability, run‐length distribution and other parameters of key importance for synchronization recovery. All the code rates achievable by the examined turbo code are considered and analysed. We demonstrate that the behaviour of the CCSDS turbo code is generally good, satisfactorily matched with practical requirements, and better than more conventional solutions included in the previous standards. Some critical conditions are also discussed, their meaning interpreted and suitable countermeasures proposed. Copyright © 2002 John Wiley & Sons, Ltd.
Calculating the bulk vacancy formation energy (Ev) for a Schottky defect in a perfect Cu(111), Cu(100) and a Cu(110) single crystal
Authors: Terblans J. J.
Published: October 2002

A study has been made of the bulk vacancy formation energy (Ev) of Cu by calculating the bulk vacancy formation energy for Cu single crystals with different surface orientations ($E_{v}^{(111)} \sim 1.54\ \hbox{eV},\ E_{v}^{(100)} \sim 1.34\ \hbox{eV}$ and $E_{v}^{(110)} \sim 1.07\ \hbox{eV}$). The calculations were performed with the empirical many‐body potentials of Sutton and Chen. The calculations indicate a significant difference in the bulk vacancy formation energy under different surface orientations. The bulk vacancy formation energies were also used to calculate theoretical bulk diffusion coefficients beneath the different surface orientations. These theoretical bulk diffusion coefficients were compared with experimental bulk diffusion coefficients that were calculated from kinetic bulk to surface segregation measurements of Sb that segregates to a Cu(111) and a Cu(110) surface. The calculated bulk diffusion coefficients and the experimental bulk diffusion coefficients showed the same trend regarding the different surface orientations. Copyright © 2002 John Wiley & Sons, Ltd.
Leptin receptor isoform expression in rat osteoblasts and their functional analysis
Authors: Lee Yun-Jung , Park Jung-Hyun , Ju Sung-Kyu , You Kwan-Hee , Ko Jea Seung , Kim Hyun-Man
Published: October 2002

The genetic defect in producing the adipose hormone leptin results among others in a drastic increase of bone mass. The current understanding is that under normal circumstances, osteoblast activity is indirectly suppressed by a hypothalamic relay induced by leptin‐signalling in the brain. To investigate whether leptin might also regulate osteoblast activity in a direct manner, expression of leptin receptors in rat osteoblasts was determined and their functionality was analyzed upon recombinant leptin treatment. Reverse transcription‐PCR confirmed the expression of four among the six currently described receptor isoforms, which were also able to transduce cell signalling as shown by STAT3 phosphorylation after activation.
Antitumor activity of interleukin‐21 prepared by novel refolding procedure from inclusion bodies expressed in Escherichia coli
Authors: Asano Ryutaro , Kudo Toshio , Makabe Koki , Tsumoto Kouhei , Kumagai Izumi
Published: October 2002

Interleukin‐21 (IL‐21) has recently been identified as a novel 4‐helix‐bundle type I cytokine possessing a cytokine receptor γ chain essential for the immune response. We report the preparation and functional characterization of Escherichia coli‐expressed recombinant human IL‐21 (rIL‐21). The rIL‐21, expressed as insoluble inclusion bodies in E. coli, was solubilized and then refolded by using a modified dialysis method. The introduction of redox reagents during refolding led to a dramatic increase in the refolding efficiency. Circular dichroism spectrum analysis showed that the refolded rIL‐21 had an α‐helix as a secondary structure, which is a characteristic of type I cytokines. Flow cytometry confirmed previous reports that rIL‐21 binds to CD3‐activated T cells (T‐LAK) and to cell lines Raji, HL60, and Jurkat. rIL‐21 stimulated the proliferation of T‐LAK but not peripheral blood mononuclear cells, and this effect seems to be identical to that of co‐stimulation with anti‐CD3 antibody. Growth inhibition assay indicated that enhancement of the cytotoxicity of T‐LAK to the human bile duct carcinoma TFK‐1 depended on the concentration of rIL‐21. Thus, refolded rIL‐21 had activity identical to that of authentic IL‐21 and enhanced the anti‐tumor activity of T‐LAK. These conclusions suggest the potential use of the refolded cytokine in adoptive immunotherapy using T‐LAK cells and in the discovery of other functions of the cytokine.
Structural insight into gene duplication, gene fusion and domain swapping in the evolution of PLP‐independent amino acid racemases
Authors: Liu Lijun , Iwata Kousuke , Yohda Masafumi , Miki Kunio
Published: October 2002

The X‐ray crystal structure has revealed two similar α/β domains of aspartate racemase (AspR) from Pyrococcus horikoshii OT3, and identified a pseudo mirror‐symmetric distribution of the residues around its active site [Liu et al. (2002) J. Mol. Biol. 319, 479–489]. Structural homology and functional similarity between the two domains suggested that this enzyme evolved from an ancestral domain by gene duplication and gene fusion. We have expressed solely the C‐terminal domain of this AspR and determined its three‐dimensional structure by X‐ray crystallography. The high structural stability of this domain supports the existence of the ancestral domain. In comparison with other amino acid racemases (AARs), we suggest that gene duplication and gene fusion are conventional ways in the evolution of pyridoxal 5′‐phosphate‐independent AARs.
Transcriptional activator, AoXlnR, mediates cellulose‐inductive expression of the xylanolytic and cellulolytic genes in Aspergillus oryzae
Authors: Marui Junichiro , Kitamoto Noriyuki , Kato Masashi , Kobayashi Tetsuo , Tsukagoshi Norihiro
Published: October 2002

AoXlnR was isolated as a transcriptional activator of the major xylanase gene, xynF1, in Aspergillus oryzae. To investigate the spectrum of genes under the control of AoXlnR, expression of the xylanolytic and cellulolytic genes in an A. oryzae wild type strain, an AoxlnR disruptant and an AoXlnR overexpressed strain was analyzed by Northern blotting. AoXlnR mediated expression of at least four xylanolytic genes and four cellulolytic genes when induced by xylan and D‐xylose. Moreover, AoXlnR was newly found to mediate the cellulose‐inductive expression of the xylanolytic genes as well as the cellulolytic genes.
Supply chains and compatibility among components in product design
Authors: Singhal Jaya , Singhal Kalyan
Published: October 2002

Two problems in designing and developing a product are directly tied into effective management of the marketing/operations interface. We first consider technological incompatibility between pairs of alternatives for different components to identify feasible product designs at various stages of product‐development, from screening to the final design. We then consider experts’ judgment on compatibility between pairs of alternatives for different attributes to generate product ideas and to perform a preliminary screening. This expert‐based approach can be used in conjunction with other expert‐based approaches or consumer‐based approaches to identify potentially desirable product ideas. The methodology developed here includes explicit simultaneous consideration of product, process, and supply chain development and it is applicable to the entire spectrum of product novelty, from radical to incremental innovation. We also describe a real‐world application.
Effect of supply chain integration on the relationship between diversification and performance: evidence from Japanese and Korean firms
Authors: Narasimhan Ram , Kim Soo Wook
Published: October 2002

Supply chain strategies and practices depend on not only the nature of the business, the competitive environment, and technological intensity of the product, but also on product and market characteristics. Consequently, supply chain integration (SCI) strategies should be evaluated in the light of a company’s market and product strategies. This paper examines the effect of SCI on the relationship between diversification and a firm’s competitive performance. The results of the study can be useful in integrating supply chain strategy into market and product diversification (PD) strategy. By comparing the main and interaction effects of SCI and diversification on performance, the paper shows that SCI strategy modifies the relationship between diversification and performance. Additionally, it is argued that coordinated use of SCI and diversification strategies has a significant effect on firm performance.
Quasilinear hyperbolic equations with hysteresis
Authors: Visintin Augusto
Published: October 2002

Plasticity, ferromagnetism, ferroelectricity and other phenomena lead to quasi-linear hyperbolic equations of the form

\frac{\partial ^{2}}{\partial t^{2}}\left[u + F\left(u\right)\right] + Au = f,

where is a (possibly discontinuous) hysteresis operator, and

A

is a second order elliptic operator. Existence of a solution is proved for an associated initial- and boundary-value problem in the framework of Sobolev spaces. The argument is based on the dissipation properties of hysteresis, and can be applied to a large class of hysteresis operators, including the classic Preisach model.

Plusieurs phénomènes (plasticité, ferro-magnétisme, ferro-électricité, etc.) conduisent à la formulation d'une équation hyperbolique quasilinéaire de la forme

\frac{\partial ^{2}}{\partial t^{2}}\left[u + F\left(u\right)\right] + Au = f,

ici

F

est un opérateur d'hystérésis éventuellement discontinu, et

A

est un opérateur elliptique du deuxième ordre. On démontre l'existence d'une solution faible pour un problème aux limites et aux valeurs initiales associé à cette équation. L'argument est basé sur les propriétés de dissipation de l'hystérésis, et s'applique à une large classe d'opérateurs, qui inclut le modèle classique de Preisach.
Quality of life and standard of living in a randomly selected group of psychiatrically disabled people in Sweden 2 years after a psychiatry reform
Authors: Carlsson I. , Frederiksen S.-O. , Gottfries C.-G.
Published: October 2002

In Sweden, a psychiatry reform, aimed at improving the living conditions of the psychiatrically disabled, came into force in 1995. The aim of the present study was to evaluate the impact of the reform by investigating quality of life and standard of living 2 years later in a randomly selected group of people with longstanding psychiatric disability. Self-ratings and interviews were conducted in a study group and a control group. The study group consisted of 19 women and 18 men (mean age 46.1 years) diagnosed with neurosis, schizophrenia or affective disorder. The control group consisted of 19 women and 17 men (mean age 48.7 years). Self-rated quality of life was significantly poorer in the study group (P < 0.0001, unpaired t-test), and so was housing (P < 0.001, test of similar proportions in independent samples). We found no significant positive correlation between subjective quality of life and standard of living in either group but a significant negative correlation in the control group (P < 0.05; r = 0.40, Pearson correlation coefficient). The results suggest that, in 1997, people with longstanding psychiatric disability still had poorer quality of life than the general population. This may be due to factors other than outward standard of living.
Are bipolar I depressive patients less responsive to treatment with antidepressants than unipolar depressive patients? Results from a case control study
Authors: Bottlender R. , Rudolf D. , Jäger M. , Strauss A. , Möller H.-J.
Published: October 2002

The increasing evidence that bipolar and unipolar affective disorders have different biological etiologies and courses of illness has been associated with an intensifying interest in specific treatment regimens for both disorders during the last decade. In this context, the question arose whether antidepressants exert similar efficacy in the acute treatment of bipolar compared to unipolar depression. Although the clinical impression does not indicate substantial differences in the efficacy of antidepressants between these groups of patients, empirical databases concerning this topic are rare. The present study compared the efficacy of antidepressants in 50 unipolar and 50 bipolar depressed inpatients (ICD-9 criteria) under naturalistic treatment conditions. Both groups of patients were mahed for age, gender and duration of illness. Clinical assessments of status at the time of admission and at discharge were used to rate response to antidepressant treatment. Analyses of the data revealed that both groups of patients needed the same time for treatment response and did not show any significant differences in ouome measures at discharge. These findings do not concur with the hypothesis formulated by some experts in the field of affective disorders that antidepressants are less effective in the acute treatment of bipolar depressed patients compared to unipolar depressed patients.
The International Diversification Fallacy of Exchange-Listed Securities
Authors: Russell Judson W.
Published: October 2002

This paper reviews various investment vehicles and examines their international diver- sification potential. The primary focus is on the ability of U.S. exchange-listed investments such as closed-end country funds, American depository receipts (ADRs), and multinational corporations (MNCs) to provide a diversification effect similar to direct investment inforeign equity. The results show that the U.S. exchange-listed securities included in this study behave more like the host exchange than their home exchange. This result suggests that these U.S. exchange-listed securities, on average, donotperformaninternational diversification rolefor U.S.investors.
Term Spreads and Predictions of Bond and Stock Excess Returns
Authors: Domian Dale L. , Reiehenstein William
Published: October 2002

Several studies conclude that a long-short term spread, in conjunction with one or more other variables, jointly predict returns on long-term corporate bonds and stocks. We extend these studies by examining the predictive content of intermediate-short term spreads, and by examining regressions of excess returns on 1.5-year to 20-year Trea- sury bonds. We show that the bond market prices an intermediate-short term spread, and not a long-short spread. We believe individuals should vary their debt-equity mix with the level of a default risk premium or the stock market's dividend yield, and vary their debt portfolios' maturity with an intermediate-short term spread.
Performance Persistence of Experienced Mutual Fund Managers
Authors: Porter Gary E. , Trifts Jack W.
Published: October 2002

This study examines the performance of 93fund managers over the 10 year period 1986 through 1995 using relative percentile ranks based on quarterly compounded, annual total returns measured against funds with the same investment objective. On average, managers with lO-year track records at the samefund do not perform better than managers with shorter track records. Also, for these experienced managers, superior performance in onefive-year period is not predictive of superior performance over the next five years. However, inferior performance persists, particularly for funds with above average expense ratios.
Personal Financial Planning (2nd edition)
Authors: Kahl Douglas
Published: October 2002

NA
Peripheral Deletion of Autoreactive CD8 T Cells by Cross Presentation of Self-Antigen Occurs by a Bcl-2–inhibitable Pathway Mediated by Bim
Authors: Davey Gayle M. , Kurts Christian , Miller Jacques F.A.P. , Bouillet Philippe , Strasser Andreas , Brooks Andrew G. , Carbone Francis R. , Heath William R.
Published: October 2002

By transgenic expression of ovalbumin (OVA) as a model self antigen in the β cells of the pancreas, we have shown that self tolerance can be maintained by the cross-presentation of this antigen on dendritic cells in the draining lymph nodes. Such cross-presentation causes initial activation of OVA-specific CD8 T cells, which proliferate but are ultimately deleted; a process referred to as cross-tolerance. Here, we investigated the molecular basis of cross-tolerance. Deletion of CD8 T cells was prevented by overexpression of Bcl-2, indicating that cross-tolerance was mediated by a Bcl-2 inhibitable pathway. Recently, Bim, a pro-apoptotic Bcl-2 family member whose function can be inhibited by Bcl-2, was found to play a critical role in the deletion of autoreactive thymocytes, leading us to examine its role in cross-tolerance. Bim-deficient T cells were not deleted in response to cross-presented self-antigen, strongly implicating Bim as the pro-apoptotic mediator of cross-tolerance.
The transition from apprenticeship training to work
Authors: Franz Wolfgang , Zimmermann Volker
Published: October 2002

This econometric study deals with the question as to what extent apprentices, after successfully completing their training, stay with the firm that supplied their training and, if so, how long that job tenure holds. Determinants of both decisions can be seen from both the employer’s and the employee’s viewpoint. These firms are interested in employing apprentices in order to collect the returns from their investment in their training, which frequently is associated with net costs. On the other hand, the firms dismiss apprentices if training is viewed by themselves as a screening device or if apprentices are engaged in work for which, in terms of wages, they are too expensive afterwards. The young trained worker bases his or her decision to stay or to leave on considerations such as experimenting with several jobs.
Mapping product usability
Authors: Babbar Sunil , Behara Ravi , White Edna
Published: October 2002

It is not sufficient for firms to deliver products that have technical excellence. Products should be easy to use and fit in with the work practices, activities and context of the consumer. Product usability is now recognized as a critical dimension of product quality. Product usability is defined by product attributes that address the physical, cognitive and emotional needs of intended users. Based on a database of documented real‐world customer experiences with manufactured products in use, this research maps the categories of product usability using an affinity diagram. The resulting affinity diagram and the insights it provides can help managers design products that better meet the needs of their customers. Limitations of the study and the implications of its findings are also discussed.
Foreign expansion strategy and performance
Authors: José Mas‐Ruiz Francisco , Luis Nicolau‐Gonzálbez Juan , Ruiz‐Moreno Felipe
Published: October 2002

The aim of this study is to examine the determining factors of a firm’s performance, as a direct consequence of its diversification strategy in its expansion into foreign markets, considering certain factors like the market, the product and the company itself. As a novelty, the methodology employed uses the event‐study to estimate the excess of returns generated by its shares on the Stock Market, based on a sample of 35 expansion announcements into external markets corresponding to 11 diversifying companies. A regression analysis is also carried out to examine the impact of these factors, market, product and company, on the excesses in returns observed. The empirical application, carried‐out in Spain, has allowed us to detect that, on average, the impact of the news about a company’s expansion on the returns on its shares is positive; its determining factors being the speciality of the product offered and the level of development in the target country.
Is gender stereotyping in advertising more prevalent in masculine countries?
Authors: Odekerken‐Schröder Gaby , De Wulf Kristof , Hofstee Natascha
Published: October 2002

The objective of this study is to test whether gender stereotyping in printed advertising is more prevalent in masculine as opposed to feminine countries. We consider this to be important, as advertising is generally more influential than literature in spreading stereotypical ideas, given its high accessibility. Moreover, the way in which sexes are portrayed in advertising affects people’s perceptions of gender roles in real life. Using content analysis, we collected empirical data on gender stereotyping of women depicted in 946 printed advertisements from two European countries widely differing in their level of masculinity – the UK and The Netherlands. The results indicate that a country’s masculinity index is hardly related to the use of gender stereotyping in printed advertising, potentially implying that other factors underlie the use of gender stereotyping.
Innovation and heterogeneous knowledge in managerial contact networks
Authors: Rodan Simon
Published: October 2002

Innovation, particularly in a dynamic environment, is crucial to a firm’s competitiveness. We test the hypothesis that managers’ performance, particularly their innovativeness, is related to the diversity of knowledge to which they are exposed in their interactions with colleagues. In a study of 106 managers in a high technology company, we find their performance benefits from increasing diversity of knowledge among their contacts. However, the effect of knowledge heterogeneity depends on the presence of sparse local networks. The joint influence of heterogeneity and sparse network structure is stronger for managerial innovation than for a more general measure of managerial performance. This suggests that the link between knowledge heterogeneity and performance relies on a process of knowledge synthesis involved in the generation of new ideas, with sparse networks affording managers the local autonomy needed for their development and implementation.
DUAL METRICS AND NONGENERIC SUPERSYMMETRIES FOR A CLASS OF SIKLOS SPACE–TIMES
Authors: BALEANU D. , BAŞKAL S.
Published: October 2002

The presence of Killing–Yano tensors implies the existence of nongeneric supercharges in spinning point particle theories on curved backgrounds. Dual metrics are defined through their associated nondegenerate Killing tensors of valence two. Siklos space–times, which are the only nontrivial Einstein spaces conformal to nonflat pp-waves are investigated with regard to the existence of their corresponding Killing and Killing–Yano tensors. It is found that a class of Siklos space–times admit dual metrics and nongeneric supercharges.
Oxidative Stress and Stress-Activated Signaling Pathways: A Unifying Hypothesis of Type 2 Diabetes
Authors: Evans Joseph L. , Goldfine Ira D. , Maddux Betty A. , Grodsky Gerold M.
Published: October 2002

In both type 1 and type 2 diabetes, the late diabetic complications in nerve, vascular endothelium, and kidney arise from chronic elevations of glucose and possibly other metabolites including free fatty acids (FFA). Recent evidence suggests that common stress-activated signaling pathways such as nuclear factor-κB, p38 MAPK, and NH2-terminal Jun kinases/stress-activated protein kinases underlie the development of these late diabetic complications. In addition, in type 2 diabetes, there is evidence that the activation of these same stress pathways by glucose and possibly FFA leads to both insulin resistance and impaired insulin secretion. Thus, we propose a unifying hypothesis whereby hyperglycemia and FFA-induced activation of the nuclear factor-κB, p38 MAPK, and NH2-terminal Jun kinases/stress-activated protein kinases stress pathways, along with the activation of the advanced glycosylation end-products/receptor for advanced glycosylation end-products, protein kinase C, and sorbitol stress pathways, plays a key role in causing late complications in type 1 and type 2 diabetes, along with insulin resistance and impaired insulin secretion in type 2 diabetes. Studies with antioxidants such as vitamin E, α-lipoic acid, and N-acetylcysteine suggest that new strategies may become available to treat these conditions.
A Novel Three-dimensional Structure Based on Both μ8-Bridging Benzene-1,2,4,5-tetracarboxylate and μ2-Bridging Oxalate
Authors: Zhang Li-Juan , Xu Ji-Qing , Shi Zhan , Zhao Xiao-Li , Wang Tie-Gang
Published: October 2002

This novel crystal structure of the coordination polymers {[M(μ8-bta)1/2(μ2-C2O4)1/2]·(H2O)4}n (1: M=CoIII; 2: M=FeIII; bta = benzene-1,2,4,5-tetracarboxylate) is based on both bta and oxalate as bridging ligands and contains helical chains composed of left-handed and right-handed helices interlaced in pairs.
Synthesis of Diamond Cylinders with Triangular and Square Cross Sections Using Anodic Porous Alumina Templates
Authors: Yanagishita Takashi , Nishio Kazuyuki , Nakao Masashi , Fujishima Akira , Masuda Hideki
Published: October 2002

Highly ordered arrays of diamond cylinders with square and triangular cross sections were prepared by CVD synthesis using anodic porous alumina templates with modified pore shapes. The CVD synthesis of diamond was carried out using a microwave enhanced CVD apparatus using alumina templates. By removing the alumina template in concentrated phosphoric acid, an ordered array of cylinders with a uniform size and shape was obtained. The obtained diamond cylinders could be isolated, and yielded the shape- and size-controlled diamond particles.
Poor response to prednisolone of idiopathic thrombocytopenia with human T‐lymphotropic virus type I infection
Authors: Matsushita Kakushi , Arima Naomichi , Ohtsubo Hideo , Fujiwara Hiroshi , Arimura Kosei , Kukita Toshimasa , Ozaki Atsuo , Hidaka Shiroh , Matsumoto Tadashi , Tei Chuwa
Published: October 2002

We describe the unique clinical characteristics of patients with idiopathic thrombocytopenic purpura (ITP) who are infected by human T‐lymphotropic virus type I (HTLV‐I). Thirty‐seven patients with ITP were examined in the present study: 10 patients had HTLV‐I infection, and the remaining 27 did not. The mean age of the group with HTLV‐I infection was significantly older than that of the group without infection (57.8 ± 14.0 and 42.4 ± 20.1, P = 0.022). The difference in mean platelet counts at diagnosis between the two groups was not significant, 29 × 109/L and 21 × 109/L, respectively. The levels of platelet associated IgG, red blood cell count, white blood cell count, bone marrow cell count, and megakaryocyte count did not show any significant difference. Nine patients in the group with HTLV‐I infection were treated with prednisolone (1 mg/kg, daily oral). Only 3 of them responded to the therapy (one complete response [CR] and two partial responses [PR]). However, 17 of 22 patients not infected with HTLV‐I were treated with prednisolone successfully: 14 patients achieved CR, and 3 patients achieved PR. There was a significant difference in response to prednisolone between the two groups (P = 0.034). Two patients with the infection and one patient without the infection achieved CR with splenectomy. These results suggest that HTLV‐I infection may cause immune thrombocytopenia by a different mechanism than classical ITP; HTLV‐I may modify the clinical features of ITP through an unknown immune pathway. Am. J. Hematol. 71:20–23, 2002. © 2002 Wiley‐Liss, Inc.
Metal fatigue, Wicksell transform and extreme values
Authors: Takahashi Rinya , Sibuya Masaaki
Published: October 2002

The fatigue strength of high‐strength steel is closely related to the largest size of non‐metallic inclusions in the region of maximum stress of the steel. Hence, it is necessary to predict the largest size of the inclusions based on the size data measured in microscopic view‐fields of planar sections of a specimen. A statistical problem is the inference on the distribution of unmeasurable extreme values from the observations on its Wicksell transform. In this paper, the authors' previous works based on a parametric model are reviewed, and current research activities based on alternative models are introduced. Copyright © 2002 John Wiley & Sons, Ltd.
Antimetabolite incorporation into DNA: Structural and thermodynamic basis for anticancer activity
Authors: Gmeiner William H.
Published: October 2002

Antimetabolites are a class of effective anticancer drugs that structurally resemble naturally occurring biochemicals and interfere in essential biochemical processes. In this review, the recent literature describing investigations of the structural and thermodynamic basis for the anticancer activity of three antipyrimidines [1‐β‐D‐arabinofuranosyl cytidine (AraC). 2′,2′‐difluoro deoxycytidine (dFdC), and 5‐fluoro‐2′‐deoxyuridine (FdUrd)] is summarized. Our laboratory, and others, have shown that misincorporation of any of these three antipyrimidines into DNA perturbs the structure and decreases the stability of duplex DNA. These data are useful for rationalizing the effects of antipyrimidine misincorporation on the activities of proteins required for DNA replication and repair such as DNA topoisomerase 1 and DNA polymerases. The studies completed to date and summarized in this review demonstrate the utility of investigations into the structure–function relationships between antipyrimidine‐substituted DNA complexed with DNA‐modifying proteins for the purpose of understanding the basis for effective antipyrimidine cancer chemotherapy and the future design of novel anticancer drugs. © 2002 Wiley Periodicals, Inc. Biopolymers (Nucleic Acid Sci) 65: 180–189, 2002
Long‐term follow‐up of patients with giant cell tumor of the sacrum treated with selective arterial embolization
Authors: Lin Patrick P. , Guzel Volkan B. , Moura Marcio F. , Wallace Sidney , Benjamin Robert S. , Weber Kristin L. , Morello Frank A. , Gokaslan Ziya L. , Yasko Alan W.
Published: October 2002

BACKGROUND

Giant cell tumors of the bone can behave as aggressive and sometimes lethal tumors. In the sacrum, the tumor can be extremely difficult to manage. Standard treatments, including surgery and radiation, are associated with significant complications and recurrence rates. The goal of this study is to evaluate the long‐term outcome of selective arterial embolization as an alternative treatment modality.

METHODS

From 1975 to 2001, 18 patients were treated with selective intraarterial embolization. The embolization method was a combination of Gelfoam particles and coils for peripheral and central occlusions, respectively. The number of embolizations was based on clinical symptoms, radiographic response, and the vascularity of the tumor. Nine patients received intraarterial cisplatin as part of their treatment. The median follow‐up was 105 months.

RESULTS

Of 18 patients, 14 responded favorably to embolization with improvement in pain and neurologic symptoms. Computed tomographic and magnetic resonance imaging scans showed reossification and stabilization of tumor size. Arteriograms showed diminished vascularity. With long‐term follow‐up, three patients developed late disease recurrences within the sacrum. Kaplan–Meier analysis showed that the risk of local recurrence is 31% at 10 years and 43% at 15 and 20 years. The long‐term outcome was not affected by intraarterial cisplatin. There was one death that occurred 1 day after embolization.

CONCLUSIONS

Most patients demonstrate an objective early radiographic response to embolization. Long‐term follow‐up shows that the response is durable in approximately one half of the patients. Given the potential morbidity of other treatments, embolization should be included in the armamentarium of treatment for this difficult disease. Embolization may be used alone or in conjunction with other therapy. Long‐term follow‐up is recommended for all patients because late disease recurrence or sarcomatous change can occur. Cancer 2002;95:1317–25. © 2002 American Cancer Society.

DOI 10.1002/cncr.10803
Rock creep and the development of the Niagara cuesta
Authors: Barlow John
Published: October 2002

This work addresses the post‐glacial development of the Niagara Escarpment, specifically the east‐facing scarp slopes between Hamilton and Collingwood. The escarpment is one of a series of scarps that shape the Great Lakes Basin. One interpretation suggests that the escarpment has evolved through homoclinal recession to the west. It is therefore viewed as an erosional feature brought about due to fluvial action on the weaker shale formations that underlie the cap rock. However, the deposition of large amounts of drift during the Pleistocene glaciation has resulted in the disruption of the preglacial drainage pattern within the Great Lakes Basin. Therefore, the current drainage is typically orthogonal to the scarp face with an absence of fluvial action along the base. Consequently, the cuesta is experiencing an extremely slow rate of retreat. Conventional thinking on the evolution of the present morphology suggests that it developed rapidly following deglaciation due to periglacial processes. The concept of the escarpment as a relict feature during the Holocene therefore pervades the modern literature.

However, the cambering of the cap rock towards the scarp face and the apparent motion of individual joint‐bounded blocks indicates that in the absence of exogenetic processes, a slow development due to endogenetic processes has dominated the modern development of the escarpment. It has been proposed that the present morphology of the cliffed sections may be due to deformation within the shale layers. In order to test this hypothesis, the rheology of the rocks that form the escarpment was tested and compared to the gravitational stresses that would be expected within the rock mass. The results indicate that the compressive strength of the shale layers of the Cabot Head Formation is lower than the expected effective stresses. It is therefore concluded that in the absence of high confining stresses, as would be expected near the cliff face, slow plastic deformation within this formation is occurring. The morphological expression of this deformation is seen in the cambering of the escarpment, the dilation of pre‐existing joints, and the rotation of joint‐bounded blocks. Copyright © 2002 John Wiley & Sons, Ltd.
In vivo biocompatibility testing of peek polymer for a spinal implant system: A study in rabbits
Authors: Rivard Charles‐H , Rhalmi Souad , Coillard Christine
Published: October 2002

We are developing a new spinal implant system (SIS) without fusion (bone graft). This SIS is made from two materials, metal and polyetheretherketone (PEEK) polymer. The Food and Drug Administration recommended testing in vivo, in an animal model, whether the PEEK polymer could be used in a SIS without any harm of wear debris to the nervous tissue (spinal cord and nerve roots). The objective was to evaluate the biological response of the spinal cord and nerve roots (dura mater) to PEEK polymer particles. Twenty‐four female New Zealand white rabbits were used. The rabbits were divided into three groups: test (n = 12), control (n = 9), and sham (n = 3). During the surgery, the test group received the PEEK particle injections (5 × 107 particles per site, lumbar and thoracic), while the control group received only the vehicle (0.9% saline solution). The sham group had the same surgical approach without injection. In each group, the rabbits were euthanized at 1, 4, and 12 weeks postsurgery. The macroscopic and semiquantitative histologic analyses of the spinal cords (dura mater) showed normal vascularization and particle adherence to the connective tissue especially at the injection sites. Neither necrosis nor swelling of the dura mater and nerve roots was observed. The PEEK polymer is harmless to the spinal cord; thus it might be used as component in the spinal implant system. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 488–498, 2002
Synthesis and photopolymerization of trifunctional methacrylates and their application as dental monomers
Authors: Chung Chan‐Moon , Kim Min‐Sung , Kim Joong‐Gon , Jang Doo‐Ok
Published: October 2002

1,1,1‐Tris[4‐(2′‐hydroxy‐3′‐methacryloyloxypropoxy)phenyl]ethane (THMPE) and tris[4‐(2′‐hydroxy‐3′‐methacryloyloxypropoxy)phenyl]methane (THMPM) were synthesized and evaluated as base monomers in a dental composite system. The photopolymerization reactivity of the trifunctional methacrylates was similar to that of conventional 2,2‐bis[4‐(2′‐hydroxy‐3′‐methacryloyloxy‐propoxy)phenyl]propane (bis‐GMA). Of the three monomers (THMPE, THMPM, and bis‐GMA), THMPE has the greatest molecular volume, and its composite showed the lowest photopolymerization shrinkage of the composites derived from the three monomers. The water‐solubility values for the light‐activated composite resins formulated with THMPE and THMPM were much lower than that for a control bis‐GMA composite. The trimethacrylates were not leached out into water from their corresponding photo‐cured composites whereas the difunctional bis‐GMA was eluted from its composite. The water sorption and flexural strength of the composite resins based on THMPE and THMPM were comparable to those of the bis‐GMA composite. THMPE is promising for application as a photocurable dental monomer because of its good polymerization reactivity along with relatively low curing shrinkage and water‐solubility of its photo‐cured composite. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 622–627, 2002
Presynaptic inhibition of olfactory receptor neurons in crustaceans
Authors: Wachowiak Matt , Cohen Lawrence B. , Ache Barry W.
Published: October 2002

Presynaptic inhibition of transmitter release from primary sensory afferents is a common strategy for regulating sensory input to the arthropod central nervous system. In the olfactory system, presynaptic inhibition of olfactory receptor neurons has been long suspected, but until recently could not be demonstrated directly because of the difficulty in recording from the afferent nerve terminals. A preparation using the isolated but intact brain of the spiny lobster in combination with voltage‐sensitive dye staining has allowed stimulus‐evoked responses of olfactory receptor axons to be recorded selectively with optical imaging methods. This approach has provided the first direct physiological evidence for presynaptic inhibition of olfactory receptor neurons. As in other arthropod sensory systems, the cellular mechanism underlying presynaptic afferent inhibition appears to be a reduction of action potential amplitude in the axon terminal. In the spiny lobster, two inhibitory transmitters, GABA and histamine, can independently mediate presynaptic inhibition. GABA‐ and histaminergic interneurons in the lobster olfactory lobe (the target of olfactory receptor neurons) constitute dual, functionally distinct inhibitory pathways that are likely to play different roles in regulating primary olfactory input to the CNS. Presynaptic inhibition in the vertebrate olfactory system is also mediated by dual inhibitory pathways, but via a different cellular mechanism. Thus, it is possible that presynaptic inhibition of primary olfactory afferents evolved independently in vertebrates and invertebrates to fill a common, fundamental role in processing olfactory information. Microsc. Res. Tech. 58:365–375, 2002. © 2002 Wiley‐Liss, Inc.
Epstein‐Barr virus (types 1 and 2) in the tear film in Sjogren's syndrome and HIV infection
Authors: Willoughby C.E. , Baker K. , Kaye S.B. , Carey P. , O'Donnell N. , Field A. , Longman L. , Bucknall R. , Hart C.A.
Published: October 2002

Evidence of Epstein‐Barr virus (EBV) shedding in the saliva and tear film has been sought to explain the pathogenesis of the oral and ocular features of Sjogren's syndrome. Patients with human immunodeficiency virus (HIV) infection are purported to have a higher incidence of keratoconjunctivitis sicca. Twenty patients with definite Sjogren's syndrome (primary and secondary), 19 with HIV infection, and 15 normal controls were recruited and studied. Human herpes viruses (EBV 1 and 2, CMV, HZV, and HSV‐1) in tear film were detected by polymerase chain reaction of DNA extracted from Schirmer strips. HSV‐1, VZV, and CMV were not detected in any tear samples. EBV‐1 DNA was found in the tear film of 4 patients with Sjogren's syndrome, which was not significantly different from the control group (P = 0.18). Twelve patients with HIV infection had evidence of EBV‐1 in their tears, which was significantly different from controls (P = 0.0002) and patients with Sjogren's syndrome (P = 0.014). EBV‐2 was found in 3 patients with HIV and in 1 patient with secondary Sjogren's syndrome, and was always found as a co‐infection with EBV‐1 (P = 0.01). This represents the first report examining EBV types 1 and 2 in the tear film and also EBV in the tear film of patients with HIV. Shedding of EBV in the tear film was not related to the presence of keratoconjunctivitis sicca in Sjogren's syndrome. EBV‐2 co‐infection with EBV‐1 has not been previously reported in the tear film. EBV infection is abnormally regulated in Sjogren's syndrome and HIV, and it is likely that the presence of EBV in the tear film is related to the patients' altered immune status. J. Med. Virol. 68:378–383, 2002. © 2002 Wiley‐Liss, Inc.