bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of insulin‐like growth factor binding protein‐3 in breast cancer cell growth
Authors: Schedlich Lynette J. , Graham Lloyd D.
Published: October 2002

The mitogenic effects of insulin‐like growth factors (IGFs) are regulated by a family of insulin‐like growth factor binding proteins (IGFBPs). One member of this family, IGFBP‐3, mediates the growth‐inhibitory and apoptosis‐inducing effects of a number of growth factors and hormones such as transforming growth factor‐β, retinoic acid, and 1,25‐dihydroxyvitamin D3. IGFBP‐3 may act in an IGF‐dependent manner by attenuating the interaction of pericellular IGFs with the type‐I IGF receptor. It may also act in an IGF‐independent manner by initiating intracellular signaling from a cell surface receptor, or by direct nuclear action, or both. The possibility of a membrane‐bound receptor is strengthened by recent studies which have identified members of the transforming growth factor‐β receptor family as having a role, either directly or indirectly, in signaling from the cell surface by IGFBP‐3. A number of growth factors and hormones stimulate the expression and secretion of cellular IGFBP‐3, which then signals from the cell surface to bring about some of the effects attributed to the primary agents. Within the cell, the apoptosis‐inducing tumor suppressor, p53, can also induce IGFBP‐3 expression and secretion. Since IGFBP‐3 upregulates the cell cycle inhibitor, p21Waf1, and increases the ratio of proapoptotic to antiapoptotic members of the Bcl family, it appears to exert the same effects on major downstream targets of cell signaling as p53 does. The nuclear localization of IGFBP‐3 has been described in a number of cell types. IGFBP‐3 may act to import IGFs or other nuclear localization signal‐deficient signaling molecules into the nucleus. It may also act directly in the nucleus by enhancing the activity of retinoid X receptor‐α and thereby promote apoptosis. All of the above phenomena will be discussed with particular emphasis on the growth of breast cancer cells. Microsc. Res. Tech. 59:12–22, 2002. © 2002 Wiley‐Liss, Inc.
Diverse roles for the Eph family of receptor tyrosine kinases in carcinogenesis
Authors: Nakamoto Masaru , Bergemann Andrew D.
Published: October 2002

The Eph family of receptor tyrosine kinases and their cell‐presented ligands, the ephrins, are frequently overexpressed in a wide variety of cancers, including breast, small‐cell lung and gastrointestinal cancers, melanomas, and neuroblastomas. In particular, one Eph family member, EphA2, is overexpressed in many cancers, including 40% of breast cancers. EphA2 can also transform breast epithelial cells in vitro to display properties commonly associated with the development of metastasis. Remarkably, the oncogenic properties of EphA2 contravene traditional dogma with regard to the oncogenic properties of a growth factor and its receptor tyrosine kinase: while stimulation of EphA2 by its ligand (ephrin‐A1) results in EphA2 autophosphorylation, the stimulation reverses the oncogenic transformation. As will be discussed in this review, the apparent dependence of oncogenicity on the dephosphorylated state of EphA2 most probably reflects the unique nature of Eph signaling. In particular, oncogenecity may depend on the capacity of unactivated EphA2 to interact with a variety of signaling molecules. As well as acting in oncogenic transformation, a growing body of evidence supports the importance of the concerted actions of ephrins and Eph molecules in tumor angiogenesis. Genetic studies, using targeted mutagenesis in mice, reveal that ephrin‐B1, ephrin‐B2, and EphB4 are essential for the normal morphogenesis of the embryonic vasculature into a sophisticated network of arteries, veins, and capillaries. Initial studies indicate that these molecules are also angiogenic in tumors, and as such represent important new targets for the development of chemotherapeutic treatments. Microsc. Res. Tech. 59:58–67, 2002. © 2002 Wiley‐Liss, Inc.
Histologic classification of ductal carcinoma in situ
Authors: Jaffer Shabnam , Bleiweiss Ira J.
Published: October 2002

Prior to the current mammographic era, ductal carcinoma in situ (DCIS) usually presented as a large mass, was classified morphologically by architecture, and treated by mastectomy. The introduction of screening mammography led to an increase in the incidence of DCIS, a decrease in the average size of DCIS, and an increased emphasis on its heterogeneous nature. Thus, a reproducible and prognostically relevant classification system for DCIS is necessary. The ultimate goal of this classification is proper selection of patients for whom lumpectomy would suffice rather than mastectomy. Features to evaluate include: extent and size of disease, adequacy of resection margins, and histology. While none of the proposed histological classification systems were endorsed at the recent Consensus Conference on the Classification of DCIS, nuclear grade was the most important feature common to most of them. Architecture was given secondary importance. By definition, DCIS is a non‐invasive clonal proliferation of epithelial cells originating in the terminal duct lobular unit, which would be expected to be monomorphic; however, it is the degree of nuclear pleomorphism that is primarily used to separate DCIS into low, intermediate, and high grades. Architecturally, DCIS has been divided into the following types: comedo, solid, cribriform, micropapillary, and papillary. Different architectural patterns and grades may be present in a given particular case; however, some combinations of patterns occur more frequently than others. Interobserver studies have shown nuclear grading to be interpreted with greater consistency than architecture, and nuclear grading methods have correlated with biological and molecular marker studies. Microsc. Res. Tech. 59:92–101, 2002. © 2002 Wiley‐Liss, Inc.
Genealogical process on a correlated fitness landscape
Authors: Wilke Claus O. , Campos Paulo R. A. , Fontanari José F.
Published: October 2002

We study with extensive numerical simulation the genealogical process of 2Nhaploid genetic sequences. The sequences are under selective pressure, and fitness values are assigned at random, but with a tunable degree of correlation to the fitness values of closely related sequences. The genealogies that we observe can be classified into three different categories, corresponding to different regimes of the mutation rate. At low mutation rates, the sequences remain localized around a small number of central sequences, which leads to trees with short pairwise distances and slow turnover of the most recent common ancestor of the population. At high mutation rates, we observe trees similar (but not identical) to those of neutral evolution. In this regime, the population drifts rapidly, and selection does not influence the distribution of fitness values in the population. The third regime, for intermediate mutation rates, is only found in strongly correlated landscapes. It resembles the one for high mutation rates in that the population drifts rapidly, but nevertheless selection still shapes the distribution of fitness values.J. Exp. Zool. (Mol. Dev. Evol.) 294:274–284, 2002.© 2002 Wiley‐Liss, Inc.
On graph irregularity strength
Authors: Frieze Alan , Gould Ronald J. , Karoński Michał , Pfender Florian
Published: October 2002

An assignment of positive integer weights to the edges of a simple graph G is called irregular, if the weighted degrees of the vertices are all different. The irregularity strength, s(G), is the maximal weight, minimized over all irregular assignments. In this study, we show that s(G) ≤ c1 n/δ, for graphs with maximum degree Δ ≤ n1/2 and minimum degree δ, and s(G) ≤ c2(log n)n/δ, for graphs with Δ > n1/2, where c1 and c2 are explicit constants. To prove the result, we are using a combination of deterministic and probabilistic techniques. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 120–137, 2002
Hamilton cycles in plane triangulations
Authors: Jackson Bill , Yu Xingxing
Published: October 2002

We extend Whitney's Theorem that every plane triangulation without separating triangles is hamiltonian by allowing some separating triangles. More precisely, we define a decomposition of a plane triangulation G into 4‐connected ‘pieces,’ and show that if each piece shares a triangle with at most three other pieces then G is hamiltonian. We provide an example to show that our hypothesis that each piece shares a triangle with at most three other pieces' cannot be weakened to ‘four other pieces.’ As part of our proof, we also obtain new results on Tutte cycles through specified vertices in planar graphs. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 138–150, 2002
A generalization of the Oberwolfach problem
Authors: El‐Zanati S. I. , Tipnis S. K. , Vanden Eynden C.
Published: October 2002

Let n > 1 be an integer and let a2,a3,…,an be nonnegative integers such that $\sum_{i=2}^{n} a_i=2^{n-1} - 1$. Then $K_{2^n}$ can be factored into $a_2 C_{2^2}$‐factors, $a_3 C_{2^3}$‐factors,…,$a_n C_{2^n}$‐factors, plus a 1‐factor. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 151–161, 2002
Regular representations of finite groups as automorphism groups of k‐tournaments
Authors: Marshall S.
Published: October 2002

It was shown by Babai and Imrich [2] that every finite group of odd order except $Z^2_3$ and $Z^3_3$ admits a regular representation as the automorphism group of a tournament. Here, we show that for k ≥ 3, every finite group whose order is relatively prime to and strictly larger than k admits a regular representation as the automorphism group of a k‐tournament. Our constructions are elementary, suggesting that the problem is significantly simpler for k‐tournaments than for binary tournaments. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 238–248, 2002
Circular chromatic number of distance graphs with distance sets of cardinality 3
Authors: Zhu Xuding
Published: October 2002

Suppose D is a subset of R+. The distance graph G(R, D) is the graph with vertex set R in which two vertices x,y are adjacent if |x−y| ∈ D. This study investigates the circular chromatic number and the fractional chromatic number of distance graphs G(R,D) with |D| = 3. As a consequence, we determine the chromatic numbers of all such distance graphs. This settles a conjecture proposed independently by Chen et al. [J. Chen, G. Chang, and K. Huang, J Graph Theory 25 (1997) 281–287 and Voigt [M. Voigt Ars Combinatoria, 52 (1999) 3–12] in the affirmative. © 2002 Wiley Periodicals, Inc. J Graph Theory 41: 195–207, 2002
Human development and regional disparities in Iran: a policy model
Authors: Noorbakhsh F.
Published: October 2002

This paper argues that the future of composite indices of development such as the Human Development Index depends on how successfully they become operational and this is more likely to be possible at the country level for a variety of reasons. With this in mind the paper proposes a method and a model for the systematic reduction of regional disparities in the Islamic Republic of Iran, a problem which is of serious concern to policy makers in Iran at present. A number of indicators of education, health and economic welfare, from the recent Human Development Report of Iran, are employed to compare 26 provinces (regions) of Iran. This paper considers (i) a method for combining the data into a composite index of development and thereby ranking provinces with respect to their overall development; (ii) it proposes a method for capturing the extent of regional disparities with respect to the selected indicators, and (iii) it suggests a way of including the results into a policy model which aims at the systematic reduction of regional disparities in Iran. For this purpose it computes a set of targets for various provinces and suggests a way of adjusting these targets. Copyright © 2002 John Wiley & Sons, Ltd.
Postnatal skeletal ontogeny in five Xantusiids (Squamata: Scleroglossa)
Authors: Anderson Maisano Jessica
Published: October 2002

The construction of a comparative database of squamate postnatal skeletal development is continued with the detailed description of the mineralization of the skeleton from birth to near maximum size in Lepidophyma gaigeae and four Xantusia taxa. Observed patterns in the sequence of appearance of epiphyseal secondary centers, ossification centers, apophyseal ossifications, and calcifications, the distribution of sesamoids, and the timing of fusions are compared and contrasted with other squamates. Xantusiids share a similar sequence of braincase fusions, but differ in the sequence of appearance of ossification centers and epiphyseal secondary centers. Relative to other squamates they exhibit an immature neonatal state of ossification, a delayed appearance of ossification centers and epiphyseal secondary centers, and an accelerated appearance of apophyses. All five xantusiid taxa possess two sesamoids previously unreported in squamates. These observations add to the growing body of evidence that morphogenesis and osteogenesis are largely independent developmental phenomena. J. Morphol. 254:1–38, 2002. © 2002 Wiley–Liss, Inc.
Loricrin‐like immunoreactivity during keratinization in lizard epidermis
Authors: Alibardi Lorenzo
Published: October 2002

Two modalities of keratinization are present in lizard epidermis: alpha (soft‐pliable corneous layers) and beta (hard and inflexible corneous layers). While beta‐keratinization is probably due to the synthesis of a new (beta)‐keratin gene product, alpha keratinization resembles in part that of mammalian epidermis. The goal of this study was to test whether a sulfur‐rich molecule similar to the mammalian corneous cell envelope protein loricrin is also present in lizard epidermis. This was done using X‐ray microanalysis and immunocytochemical and ultrastructural methods. In the epidermis of the lizard Podarcis muralis small (0.1–0.3 μm) to large (1–5 μm) keratohyalin‐like granules (KHLGs) are produced in alpha‐keratinizing cells, especially in the clear layer. Small KHLGs contain sulfur and show weak filaggrin‐like and stronger loricrin‐like immunoreactivities. The latter is also present in keratinizing alpha‐layers but is absent in the beta layers. Large KHLGs in the clear layer derive from the aggregation of the small granules with other components, including lipid material. These large granules show some loricrin‐like immunoreactivity and contain sulfur and phosphorous, histidine, but not filaggrin‐like immunoreactivity. It is suggested here that phosphorous derives from their phospholipid component. The present study shows that the modality of alpha‐keratinization of lizard epidermis resembles that of mammals and suggests that the basic molecular mechanisms of keratin aggregation and formation of the corneous cell envelope were already present in the therapsid line of reptiles from which mammals evolved. J. Morphol. 254:132–138, 2002. © 2002 Wiley‐Liss, Inc.
Targeted imaging using ultrasound
Authors: Dayton Paul A. , Ferrara Katherine W.
Published: October 2002

The discipline of medical imaging is expanding to include both traditional anatomic modalities and new techniques for the functional assessment of the presence and extent of disease. Current FDA‐approved ultrasound contrast agents are micron‐sized bubbles with a stabilizing shell. Microbubble contrast agents can be used to estimate microvascular flow rate in a manner similar to dynamic contrast‐enhanced magnetic resonance imaging (MRI). The concentration of these agents within the vasculature, reticulo‐endothelial, or lymphatic systems produces an effective passive targeting of these areas. Liquid‐filled nanoparticles and liposomes have also demonstrated echogenicity and are under evaluation as ultrasound contrast agents. Actively targeted ultrasound relies on specially designed contrast agents to localize the targeted molecular signature or physiologic system. These agents typically remain within the vascular space, and therefore possible targets include molecular markers on thrombus, endothelial cells, and leukocytes. The purpose of this review is to summarize the requirements, challenges, current progress, and future directions of targeted imaging with ultrasound. J. Magn. Reson. Imaging 2002;16:362–377. © 2002 Wiley‐Liss, Inc.
Dynamic contrast‐enhanced MRI in clinical oncology: Current status and future directions
Authors: Padhani Anwar R.
Published: October 2002

Dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) is performed after the administration of intravenous contrast medium to noninvasively access tumor vascular characteristics. DCE‐MRI techniques utilizing low‐molecular‐weight contrast media have successfully made the transition from methodological development to preclinical and clinical validation and are now rapidly becoming mainstream clinical tools. DCE‐MRI using macromolecular contrast medium (MMCM) can also assay microvascular characteristics of human tumor xenografts. MMCM approval for human use will occur soon. The success of both techniques depends on their ability to demonstrate quantitative differences of contrast medium behavior in a variety of tissues. Evidence is mounting that kinetic parameters correlate with immunohistochemical surrogates of tumor angiogenesis, including microvessel density, and with pathologic tumor grade. DCE‐MRI is being applied to monitor the clinical effectiveness of a variety of treatments, including antiangiogenic drugs. Kinetic parameter changes following treatment have correlated with histopathological outcome and patient survival. This article reviews the current clinical status of low‐molecular‐weight DCE‐MRI and reviews the potential of MMCM techniques for evaluating human tumors. Ongoing challenges faced by DCE‐MRI as clinical and research tools will be explored. J. Magn. Reson. Imaging 2002;16:407–422. © 2002 Wiley‐Liss, Inc.
MRI of the tumor microenvironment
Authors: Gillies Robert J. , Raghunand Natarajan , Karczmar Gregory S. , Bhujwalla Zaver M.
Published: October 2002

The microenvironment within tumors is significantly different from that in normal tissues. A major difference is seen in the chaotic vasculature of tumors, which results in unbalanced blood supply and significant perfusion heterogeneities. As a consequence, many regions within tumors are transiently or chronically hypoxic. This exacerbates tumor cells' natural tendency to overproduce acids, resulting in very acidic pH values. The hypoxia and acidity of tumors have important consequences for antitumor therapy and can contribute to the progression of tumors to a more aggressive metastatic phenotype. Over the past decade, techniques have emerged that allow the interrogation of the tumor microenvironment with high resolution and molecularly specific probes. Techniques are available to interrogate perfusion, vascular distribution, pH, and pO2 nondestructively in living tissues with relatively high precision. Studies employing these methods have provided new insights into the causes and consequences of the hostile tumor microenvironment. Furthermore, it is quite exciting that there are emerging techniques that generate tumor image contrast via ill‐defined mechanisms. Elucidation of these mechanisms will yield further insights into the tumor microenvironment. This review attempts to identify techniques and their application to tumor biology, with an emphasis on nuclear magnetic resonance (NMR) approaches. Examples are also discussed using electron MR, optical, and radionuclear imaging techniques. J. Magn. Reson. Imaging 2002;16:430–450. © 2002 Wiley‐Liss, Inc.
In vivo molecular imaging for planning radiation therapy of gliomas: An application of 1H MRSI
Authors: Nelson Sarah J. , Graves Edward , Pirzkall Andrea , Li Xiaojuan , Antiniw Chan Antionette , Vigneron Daniel B. , McKnight Tracy R.
Published: October 2002

Gliomas are infiltrative lesions that typically have poorly defined margins on conventional magnetic resonance (MR) and computed tomography (CT) images. This presents a considerable challenge for planning radiation and other forms of focal therapy, and introduces the possibility of both under‐treating macroscopic tumor, and over‐treating regions of normal brain tissue. New therapy systems are able to deliver radiation more precisely and accurately to irregular three‐dimensional target volumes, and have placed a premium on definition of the spatial extent of the lesion. Proton MR spectroscopic imaging (H‐MRSI) has been proposed as an in vivo molecular imaging technique that assists in targeting and predicts response to radiation therapy for patients with gliomas. The evidence that supports the use of H‐MRSI for planning radiation treatment is reviewed, together with the technical requirements for implementing data acquisition and analysis procedures in a clinical setting. Although there is room for improvement in the spatial resolution and chemical specificity obtained at the conventional field strength of 1.5 T, there are clear benefits to integrating H‐MRSI into treatment planning and follow‐up examinations. Further work is required to integrate the results of the H‐MRSI examination into the treatment planning workstation, and to improve the quality of the data using more sensitive phased array coils and higher field strength magnets. J. Magn. Reson. Imaging 2002;16:464–476. © 2002 Wiley‐Liss, Inc.
Determination of misoprostol free acid in human breast milk and serum by gas chromatography/negative ion chemical ionization tandem mass spectrometry
Authors: Watzer Bernhard , Seyberth Hannsjörg W. , Schweer Horst
Published: October 2002

To study an expected transition of misoprostol from human blood into breast milk, a novel method for the determination of its active metabolite misoprostol acid (MPA) was developed. MPA was determined in serum and breast milk samples by an isotope dilution assay using gas chromatography/negative ion chemical ionization tandem mass spectrometry (GC/NICI‐MS/MS). After addition of (15S)‐15‐methylprostaglandin E2 (15‐methyl‐PGE2) as an internal standard, MPA was extracted from both matrices using a reversed‐phase cartridge. The prostanoids were derivatized with O‐2,3,4,5,6‐pentafluorobenzylhydroxylamine hydrochloride (PFBHA) and 2,3,4,5,6‐pentafluorobenzyl bromide (PFBB) to the pentafluorobenzyl oxime (PFBO)‐pentafluorobenzyl ester (PFB) derivatives. The sample was subjected to thin‐layer chromatography with ethyl acetate–hexane (1 : 1 (v/v)) as the developing solvent. The corresponding zone was extracted. After derivatization to the trimethylsilyl ether, MPA was determined by GC/NICI‐MS/MS using the [molecule (M) − pentafluorobenzyl (PFB)]− ([P]−) ions as precursor in the negative ion chemical ionization mode. The product ions used for quantification were [P − 2TMSOH − C6F5CH2OH]− (MPA) and [P − 2TMSOH − C6F5CH2OH − CO2]−(15‐methyl‐PGE2), respectively. The limit of quantification for MPA was ∼1 pg ml−1 in breast milk and serum samples. The correlation coefficients of the calibration curves for MPA were r > 0.997 in the 0.5–2000 pg ml−1 range for both tested matrices. Copyright © 2002 John Wiley & Sons, Ltd.
Fast time‐domain characterization of finite size microstrip structures
Authors: Aygün K. , Shanker B. , Michielssen E.
Published: October 2002

A new fast integral‐equation‐based scheme for analysing electromagnetic transients on finite size microstrip structures is described. The scheme permits the analysis of structures comprised of perfect electrically conducting surfaces and wires along with lossless but potentially inhomogeneous dielectric regions. For typical microstrip structures, the computational complexity of the proposed analysis tool grows asO(NtNsvlog2Nsv), whereNtdenotes the number of time steps in the analysis,Nsv=Ns+Nv, andNsandNvrepresent the number of spatial unknowns that model currents on conducting surfaces/wires/junctions and in penetrable volumes, respectively. This complexity estimate is in stark contrast with that for classical marching‐on‐in‐time solvers, which requireO(NtNsv2) CPU resources. Copyright © 2002 John Wiley & Sons, Ltd.
Neuroprotective effect of estradiol and phytoestrogens on MPP+‐induced cytotoxicity in neuronal PC12 cells
Authors: Gélinas Sylvie , Martinoli Maria‐Grazia
Published: October 2002

A large body of experimental evidence supports a role for oxidative stress as a mediator of nerve cell death in Parkinson's disease. To better understand the cellular insult of oxidative stress on dopaminergic neurons, we studied the cytotoxic effect of the 1‐Methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) metabolite, 1‐methyl‐4‐phenyl pyridium (MPP+), on several parameters of cell distress using neuronal PC12 cells. We also measured the level of protein expression for the dopamine transporter and the estrogen receptors α and β. Since estrogens have been reported to prevent neuronal degeneration caused by increased oxidative burden, we investigated the ability of 17β‐estradiol, the stereoisomer 17α‐estradiol, and several phytoestrogens to rescue neuronal PC12 cells submitted to MPP+‐induced cytotoxicity. Our results consistently show a protective effect of 17α‐estradiol, 17β‐estradiol and certain phytoestrogens such as quercetin and resveratrol, in neuronal PC12 cells treated with MPP+. In our cellular paradigm, phytoestrogens coumestrol, genistein, and kaempferol did not revert MPP+‐induced cellular death. By Western blot, we demonstrated that administration of MPP+ alone decrease dopamine transporter expression, while treatments with MPP+ together with 17α‐estradiol, 17β‐estradiol, quercetin, or resveratrol could restore dopamine transporter protein expression to control levels. Moreover, the same treatments did not modulate α estrogen receptor or β estrogen receptor expression. By these studies, we aim to provide more evidence for the involvement of phytoestrogens in the process of neuroprotection and to test our hypothesis that some of these compounds may act as neuroprotective molecules and have a lesser hormonal effect than estrogens. © 2002 Wiley‐Liss, Inc.
Role of reactive oxygen species in hippocampal long‐term potentiation: Contributory or inhibitory?
Authors: Knapp Lauren T. , Klann Eric
Published: October 2002

Reactive oxygen species (ROS) typically are characterized as molecules involved in neurotoxicity and neurodegeneration. However, recent evidence from both neuronal and nonneuronal cells suggests that ROS also function as small messenger molecules that are normal components of signal transduction cascades during physiological processes. Consistent with this idea, ROS have been shown to be critical for hippocampal long‐term potentiation (LTP), a form of synaptic plasticity widely studied as a cellular substrate for learning and memory. On the other hand, ROS also have been shown to be involved in aging‐related impairment of LTP. This review discusses the evidence supporting the notion that ROS both contribute to normal LTP and are involved in age‐related impairment of LTP. We also discuss possible sources that might be responsible for the production of ROS after the induction of LTP. Finally, we propose a functional ROS continuum to help explain this dichotomy of ROS function in hippocampal LTP. © 2002 Wiley‐Liss, Inc.
ATP‐evoked calcium responses of radial glial (Müller) cells in the postnatal rabbit retina
Authors: Uckermann Ortrud , Grosche Jens , Reichenbach Andreas , Bringmann Andreas
Published: October 2002

Here we show that rabbit Müller cell differentiation from radial glial progenitor cells is accompanied by a decreasing capability to respond to specific stimuli (depolarization and extracellular adenosine 5′‐triphosphate [ATP]) with an elevation of intracellular calcium. Intracellular free calcium was recorded in retinal wholemounts from young (postnatal days [P] 2 to 31) and adult rabbits. Images were taken from the nerve fiber/ganglion cell layers where the endfeet of radial glial/ Müller cells can be identified after selective uptake of calcium‐sensitive dyes. The area of responding endfeet was determinded as the percentage of the total area occupied by Müller cell endfeet, as an estimate of the percentage of responding cells. In response to depolarization (50 mM potassium), an increase of intracellular free calcium occurred in 19% of cells from young postnatal retinae (P2–31) but only in 2% from adults. This depolarization‐induced calcium rise was caused both by a calcium influx from extracellular space and by an intracellular calcium release. The latter response was inhibited by the P2 receptor blocker pyridoxal phosphate 6‐azophenyl‐2′,4′‐disulfonic acid (PPADS), indicating that extracellular calcium‐independent ATP release into the extracellular space occurs during retinal depolarization. When extracellular ATP (200 μM) was applied, calcium responses were recorded in 83% of cells from young postnatal retinae (P2–6); in the course of further development, both the percentage of responding cells (7% in retinae from adult rabbits) and the amplitude of the calcium responses decreased. It is concluded that during the differentiation of immature radial glia into mature Müller cells, stimulus‐evoked intracellular calcium signaling mechanisms change. © 2002 Wiley‐Liss, Inc.
Assignments and hydrogen bond sensitivities of UV resonance Raman bands of the C8‐deuterated guanine ring
Authors: Toyama Akira , Fujimoto Naoko , Hanada Naoki , Ono Junko , Yoshimitsu Emiko , Matsubuchi Akiko , Takeuchi Hideo
Published: October 2002

Isotope‐edited Raman spectroscopy, a combination of site‐selective isotopic labeling and Raman difference spectroscopy, is a useful method for studying the structure and interaction of individual nucleic acid residues in oligonucleotides. To obtain basic data for applying isotope‐edited Raman spectroscopy to guanine residues, we studied the vibrational modes of UV resonance Raman bands of the C8‐deuterated guanine ring by examining the wavenumber shifts upon seven isotopic substitutions (2‐13C, 2‐15N, 6‐18O, 7‐15N, 8‐13C, 9‐15N and 1′‐13C). The hydrogen bond sensitivities of the Raman bands were also investigated by comparing the Raman spectra recorded in several solvents of different hydrogen bonding properties. Some of the Raman bands were found to be markers of hydrogen bonding at specific donor or acceptor sites on the guanine ring. The Raman bands, which shift on C8‐deuteration, remain in the difference spectrum between the unlabeled and C8‐deuterated guanine rings. Among them, a negative peak around 1525 cm−1 and a strong positive/negative peak pair around 1485/1465 cm−1 serve as markers of hydrogen bonding at N7 and C6O, respectively. Another weak positive/negative peak pair around 1025/1040 cm−1 is sensitive to hydrogen bonding at the proton donor sites (N1—H and N2—H2). The applicability of the hydrogen bond markers has been tested by using a 22‐mer oligonucleotide duplex containing eight guanine residues and its analog in which a single guanine residue is C8‐deuterated. The difference spectrum shows that the hydrogen bonding state of the guanine residue at the labeled position is consistent with the Watson–Crick base pair structure of DNA. Isotope‐edited Raman spectroscopy is a useful tool for studying the hydrogen bonding state of selected guanine residues in oligonucleotides. Copyright © 2002 John Wiley & Sons, Ltd.
Structural phase transitions in [(C2H5)4N]2SiF6: differential scanning calorimetry and Raman studies
Authors: Ouasri A. , Rhandour A. , Dhamelincourt M.‐C. , Dhamelincourt P. , Mazzah A. , Taibi M.
Published: October 2002

Three structural phase transitions were observed for a new tetraethylammonium compound, [(C2H5)4N]2SiF6, by means of differential scanning calorimetry. The internal vibrational modes of the [(C2H5)4N]2SiF6 compound were studied at ambient temperature and through the phase transitions with the use of Raman spectroscopy. It was concluded that the observed phase transitions are associated with the dynamics of the system and are of the order–disorder type. Copyright © 2002 John Wiley & Sons, Ltd.
Raman investigation of the low‐temperature phase transition in a liquid crystalline system: terephthalidine‐bis‐heptylaniline (TB7A)
Authors: Singh Ranjan K. , Schluecker S. , Asthana B. P. , Kiefer W.
Published: October 2002

Raman spectra of terephthalidine‐bis‐heptylaniline (TB7A) were recorded in the region 1125–1225 cm−1 from room temperature to 10 K at 18 different temperatures. The splitting of the ∼1165 cm−1 band, and the variation of the ratio of integrated intensities of the original band at ∼1165 cm−1 to the new component at 1170/1171 cm−1 reveals a solid modification. The analysis of the temperature dependence of the linewidth was made using Rakov's relation. A logarithmic plot as a function of 1/T gives two straight lines with an abrupt discontinuity, which clearly exhibits a phase transition at about 210 K. The temperature dependence of the linewidth of the ∼1165 cm−1 band was used to characterize this transition. A relatively large variation (∼3 cm−1) of the linewidth on going from 250 to 10 K in TB7A having an odd (n = 7) number of carbon atoms in the alkyl tail compared with those observed (∼1 cm−1) in other homologues having an even (n = 2 or 10) number of carbon atoms in the alkyl tail is a clear demonstration of the even–odd effect. Copyright © 2002 John Wiley & Sons, Ltd.
An extensive non‐destructive and micro‐spectroscopic study of two post‐Byzantine overpainted icons of the 16th century
Authors: Daniilia Sister , Bikiaris Dimitris , Burgio Lucia , Gavala Paulina , Clark Robin J. H. , Chryssoulakis Yannis
Published: October 2002

This work is an extensive study of two post‐Byzantine icons, ‘Our Lady, the Life‐giving Spring’ and ‘Saint Athanasios the Athonite,’ both painted during the 16th century and now kept at Saint Modestos's Church in Kalamitsi, Chalkidiki, Greece. The icons were examined using non‐destructive and microanalytical techniques, namely fluorescence photography under UV light, x‐radiography and optical microscopy, in addition to micro‐Raman and micro‐Fourier transform IR spectroscopy. This study allowed the assessment of the current state of preservation of these icons, revealed prior damage and identified in detail the pigments and materials used in the original paintings and overpaintings. Moreover, it confirmed the usefulness of this approach to the detailed evaluation of icons in general and provided significant structural data on representative portable icons of Cretan‐style religious painting. The palette for the original paintings of the two icons consists of the natural pigments caput mortuum, yellow ochre, carbon black, azurite, green earth, cinnabar, white lead, red lake and copper resinate; egg yolk was used as the binder. By contrast, the rather elementary overpaintings are of low tonality, consisting predominantly of mixtures of minium and carbon black, and also the synthetic pigments ultramarine blue, “chrome green” (Prussian blue + lead chromate), chrome yellow and lithopone. A blend of linseed oil and egg provided the binder for the pigments used. The same artist is understood from art historians to have overpainted both icons at the beginning of the 20th century. Copyright © 2002 John Wiley & Sons, Ltd.
Development of a combined confocal and scanning near‐field Raman microscope for deep UV laser excitation
Authors: Sands H. S. , Demangeot F. , Bonera E. , Webster S. , Bennett R. , Hayward I. P. , Marchi F. , Smith D. A. , Batchelder D. N.
Published: October 2002

We describe the development of a combined confocal and scanning near‐field Raman microscope for operation at deep UV wavelengths. This instrument is based upon a commercially available Raman microscope and enables far‐field and near‐field Raman spectra to be acquired from the same location on a sample. The application of the confocal and scanning near‐field microscopes was demonstrated by studies of CVD diamond films. Copyright © 2002 John Wiley & Sons, Ltd.
Raman and infrared study of (PbO)x(P2O5)(1−x) glasses
Authors: Le Saoût Gwenn , Simon Patrick , Fayon Franck , Blin Annie , Vaills Yann
Published: October 2002

The structure of binary (PbO)x(P2O5)(1−x) glasses was investigated using Raman scattering and infrared spectroscopy, over the compositional range x = 0.5–0.68. The distribution of the phosphate groups (PO2)−, (PO3)2−, (P2O7)4− and (PO4)3−, determined from the simulation of Raman spectra in the 800–1500 cm−1 wavenumber range, indicates a significant disproportionation reaction near the pyrophosphate composition and shows a phosphorus connectivity scheme in the glass structure in agreement with 31P magic angle spinning NMR results. The low‐wavenumber Raman spectra of glasses are discussed in the light of the spectra of crystals. The mode laying in the far‐infrared region and due to lead–oxygen vibrations exhibits a composition‐dependent wavenumber that correlates with bulk glass properties such as glass transition temperature. Copyright © 2002 John Wiley & Sons, Ltd.
Raman spectroscopy of the polyanionic copper(II) minerals buttgenbachite and connellite: implications for studies of ancient copper objects and bronzes
Authors: Frost Ray L. , Williams Peter A. , Martens Wayde , Kloprogge J. Theo
Published: October 2002

The minerals connellite and buttgenbachite, complex hydroxy sulfate and nitrate, respectively, of Cu(II), are rare products formed during the corrosion of bronze and brass objects. Infrared and Raman spectra of buttgenbachite and connellite were obtained at 298 and 77 K using a Raman microprobe in combination with a thermal stage. The Raman spectra show the presence of nitrate, sulfate and chloride in the mineral. Spectra of the hydroxyl‐stretching region are complex with multiple bands being observed. These observations are in agreement with the structure of the minerals in that the nitrate ion occupies two different sites and that six hydroxyl groups are crystallographically independent. Various OH stretching bands are attributed to independent hydroxyl units in the crystal structure and zeolitic water OH stretching modes. Raman spectroscopy is an excellent technique for the identification of these complex minerals and for the determination of the distribution of anions in their structure. Copyright © 2002 John Wiley & Sons, Ltd.
Raman imaging of stress‐induced phase transformation in transparent ZnSe ceramic and sapphire single crystals
Authors: Colomban Philippe , Havel Mickael
Published: October 2002

It is known that the polishing of a material can cause pressure‐induced phase transformation and modify its surface properties. Indentation was used to apply controlled perturbation on optically clear ZnSe ceramics and on α‐alumina single‐crystal wafers. New Raman bands are observed at the periphery and/or the centre of the indented area. Confocal Raman and Rayleigh imaging of the peak intensity, bandwidth and wavenumber shift show complex transformations of the indented area. Peak intensity can be used to map the surface geometry with approximately micrometre resolution. For ZnSe, the new bands (ca 235 and 248 cm−1) are assigned to the phases obtained above 5 and 34 GPa under hydrostatic pressure. Comparison is made with zirconia and corundum crystals. Stress‐induced modifications are observed on the α‐alumina wafer. They seem to be due to an unknown disordered phase rather than to a high remnant stress. The relationship between the Raman parameters and the applied stress is discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of nitrogen fertilisation on below‐ground carbon allocation in lettuce
Authors: Kuzyakov Y , Siniakina S V , Ruehlmann J , Domanski G , Stahr K
Published: October 2002

The aims of this study were to investigate the effect of nitrogen (N) fertilisation on the below‐ground carbon (C) translocation by lettuce and the CO2 efflux from its rhizosphere. Two N fertilisation levels (80 and 160 kg N ha−1) and two growth stages (43 and 60 days) were tested. 14C pulse labelling of shoots followed by 14C monitoring in the soil, roots, microbial biomass and CO2 efflux from the soil was used to distinguish between root‐derived and soil organic matter‐derived C. The 14C allocation in the below‐ground plant parts was 1.5–4.6 times lower than in the leaves. The total quantity of C translocated into the soil was much lower than in the case of cereals and grasses, amounting to 120 and 160 kg C ha−1 for low and high N respectively. N fertilisation diminished the proportion of assimilated C translocated below ground. About 5–8% of the assimilated C was respired into the rhizosphere. Root‐derived CO2 (the sum of root respiration and rhizomicrobial respiration) represented about 15–60% of the total CO2 efflux from the planted soil. Two peaks were measured in the 14CO2 efflux: the first peak (4–5 h after labelling) was attributed to root respiration, whilst the second peak (12 h after labelling) was attributed to microbial respiration of exudates. Twelve days after labelling, 0.15–0.25% of the assimilated C was found in the microbial biomass. The higher microbial activity in the lettuce rhizosphere doubled the soil organic matter decomposition rate compared with unplanted soil.

© 2002 Society of Chemical Industry
Browning, polyphenol oxidase activity and headspace gas composition during storage of minimally processed pears using modified atmosphere packaging
Authors: Soliva‐Fortuny Robert C , Biosca‐Biosca Mireia , Grigelmo‐Miguel Nuria , Martín‐Belloso Olga
Published: October 2002

Modified atmosphere packaging was used to prevent browning of minimally processed Conference pears, thus extending their shelf‐life. Colour changes as well as PPO activity were strongly influenced by the package headspace gas composition, which was determined by the packaging conditions. The initial colour of minimally processed pears was preserved for several weeks under cold storage in plastic pouches of very low O2 permeability and an initial atmosphere of 100% N2. A fractional conversion kinetic model fitted the experimental browning data with high accuracy. Colour degradation (ΔE*) of minimally processed pears occurred exponentially (kΔE = 0.019–0.077 day−1) owing to changes in lightness (kL = 0.021–0.07 day−1). In contrast, PPO exhibited a linear increase in activity which could be related to the availability of O2 in the package headspace.

© 2002 Society of Chemical Industry
Consumption of raw and fried sardine (Clupea pilchardus) as protein source of diets: effects on iron metabolism in rats
Authors: Seiquer Isabel , Aspe Teresa , Pérez‐Granados Ana M , Navarro M Pilar
Published: October 2002

The influence of fried fish consumption on dietary iron bioavailability in rats was studied. Sardines (Clupea pilchardus), raw and fried in olive oil, were used whole or defatted to prepare the samples. Five diets containing casein and the different samples as protein source were prepared. After in vitro digestion of the diets a greater proportion of soluble iron was found in the casein diet compared with the sardine diets. Five groups of rats were fed the diets over 28 days. Body weight and food intake were monitored weekly, and during days 21–28 an iron balance study was carried out. No significant differences were observed in food intake, body weight and protein efficiency ratio between groups. Absorbed and retained iron and apparent iron digestibility were higher in rats fed the sardine diets with respect to the control group, except in the whole fried sardine group. Metabolic efficiency and retention efficiency were increased in the four sardine groups. The frying process led to significant changes in the overall digestive and nutritive efficiency of dietary iron, which were different depending on whether the diets contained whole sardine or its protein. It was concluded that the consumption of sardines, whether raw or fried in olive oil, enhances dietary iron availability.

© 2002 Society of Chemical Industry
Determination of the betaine content of feed ingredients using high‐performance liquid chromatography
Authors: Chendrimada Thimmaiah P , Neto Manoel Garcia , Pesti Gene M , Davis Adam J , Bakalli Remzi I
Published: October 2002

A series of studies was conducted to establish a methodology for the accurate and efficient determination of betaine in different feed ingredients. The final methodology involves an extraction step in which the feed sample is heated for 3 h in a methanolic KOH solution using a Goldfisch apparatus. Impurities are removed by the addition of activated charcoal and concentrated (36%) HCl. After centrifugation the extractant is passed through a strong cation exchange resin (Dowex 50W‐X12, H+). The betaine retained in the column is eluted with 1.5 N HCl. A 2 ml aliquot of the elute is air dried and reconstituted with 1 ml of deionised water. HPLC separation with a cation exchange column (Partisil SCX‐10) is used for the separation of betaine from other compounds. The mobile phase is kept constant at 50 mM KH2PO4 in water, and eluted compounds are detected by UV absorbance (200 nm). The flow rate is maintained at 1.5 ml min−1. This assay is very accurate over the range of betaine concentrations from 15 to 650 µg ml−1, with a lower detection limit in feeds of approximately 500 µg g−1 when 4 g of sample is extracted. Recovery assays done with standard betaine hydrochloride and hard red wheat resulted in a consistent recovery of 80%. Betaine content was quantified in several feed ingredients, including alfalfa (1.77 mg kg−1), wheat (3.96 mg kg−1), wheat middlings (4.98 mg kg−1) and poultry meal (0.77 mg kg−1). Betaine in corn and soybean meal was not detectable by this method, even when 16 g of sample was used (<125 mg kg−1). Betaine present in several feed ingredients should influence choline supplementation to animal feeds and may have implications for human health.

© 2002 Society of Chemical Industry
Insecticidal compounds from Evodia rutaecarpa against Drosophila melanogaster
Authors: Miyazawa Mitsuo , Fujioka Jun , Ishikawa Yukio
Published: October 2002

In the course of screening for novel naturally occurring insecticides from Chinese crude drugs, the MeOH extract of the fruits of Evodia rutaecarpa Benth was found to give insecticidal activity against larvae of Drosophila melanogaster Meigen. Three alkaloids, evodiamine (1), rutaecarpine (2) and rhetsinine (3), were isolated by bioassay‐guided fractionation of the extract. Insecticidal activity against larvae of D melanogaster was demonstrated; compounds 1 and 2 gave LC50 values of 0.30 and 0.28 µmol ml−1 diet respectively. Acute toxicity against adults of D melanogaster was also found; compound 2 had the most potent activity, with an LD50 value of 3.58 µg per adult. However, compound 3 had only weak activity in this study. Therefore compounds 1 and 2 were identified as insecticidal compounds from the fruits of E rutaecarpa. Compound 3 was obtained by the photoxidation of evodiamine. Investigation of the structure–activity relationship indicated the importance of the indoloquinazoline unit at the C‐14 position.

© 2002 Society of Chemical Industry
Rehabilitation of degraded sodic lands during a decade of Dalbergia sissoo plantation in Sultanpur District of Uttar Pradesh, India
Authors: Mishra A. , Sharma S. D. , Khan G. H.
Published: October 2002

The ameliorative effect of Dalbergia sissoo, planted on sodic land at Sultanpur (26° 10′–26° 40′N, 81° 45′–82° 30′E), India, in a tropical environment, was studied at 3, 6 and 9 years of age. The soil properties of the sites improved significantly, showing marked reduction in pH, electrical conductivity (EC) and exchangeable sodium percentage (ESP) and an increase in organic carbon, nitrogen and availability of nutrients in the soil. The significant reduction in Na ion was found in all the age groups. Results showed an improvement in the soil moisture regime due to increased infiltration rate (cm hr−1), soil permeability (cm2), water‐holding capacity, field capacity and pore space whereas, the bulk density decreased significantly after successive years of planting. The effect on soil attributes was confined to surface soil in the young plantation and deeper in older plantation. Therefore, the study clearly indicated that the sodic soil could be desodified by growing D. sissoo plantations on these degraded sites. Copyright © 2002 John Wiley & Sons, Ltd.