bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cellular and molecular biology of ensheathing cells
Authors: Chuah Meng Inn , West Adrian K. 
Published: October 2002

AbstractEnsheathing cells are the glial cells that envelop olfactory axons as they course from the olfactory epithelium to the bulb. They are derived from the olfactory placode and differ from the typical glia in terms of sharing the phenotypes of both astrocytes and Schwann cells. The aims of this study are to review (1) cellular characterisation of ensheathing cells in vivo and in vitro, (2) molecular insight into their growth promoting properties, and (3) their role in olfactory development and potential function as a therapeutic agent for nerve repair. Much of the characterisation of ensheathing cell property has developed from immunohistochemical studies that have been supplemented with new molecular methodologies in recent years. Many pieces of evidence clearly indicate that ensheathing cells actively produce growth‐promoting molecules, which act in a paracrine and, in some cases, autocrine manner. However, a review of the available literature also suggests that there is a great deal that remains to be elucidated regarding the cell biology of ensheathing cells, for example, their rate of formation and turnover. In addition, the apparent antigenic heterogeneity as revealed by numerous in vitro studies warrants further analysis, particularly in view of the fact that in recent years these cells have been touted as a possible agent for central nerve repair. New molecular methodologies such as the microarray techniques will prove to be crucial for defining the unique characteristics of ensheathing cells. Microsc. Res. Tech. 58:216–227, 2002. © 2002 Wiley‐Liss, Inc.
Acceleration of Ambystoma tigrinum metamorphosis by corticotropin‐releasing hormone
Authors: BOORSE GRAHAM C. , DENVER ROBERT J. 
Published: October 2002

AbstractPrevious work of others and ours has shown that corticotropin‐releasing hormone (CRH) is a positive stimulus for thyroid and interrenal hormone secretion in amphibian larvae and that activation of CRH neurons may mediate environmental effects on the timing of metamorphosis. These studies have investigated CRH actions in anurans (frogs and toads), whereas there is currently no information regarding the actions of CRH on metamorphosis of urodeles (salamanders and newts). We tested the hypothesis that CRH can accelerate metamorphosis of tiger salamander (Ambystoma tigrinum) larvae. We injected tiger salamander larvae with ovine CRH (oCRH; 1 μg/day; i.p.) and monitored effects on metamorphosis by measuring the rate of gill resorption. oCRH‐injected larvae completed metamorphosis earlier than saline‐injected larvae. There was no significant difference between uninjected and saline‐injected larvae. Mean time to reach 50% reduction in initial gill length was 6.9 days for oCRH‐injected animals, 11.9 days for saline‐injected animals, and 14.1 days for uninjected controls. At the conclusion of the experiment (day 15), all oCRH‐injected animals had completed metamorphosis, whereas by day 15, only 50% of saline‐injected animals and 33% of uninjected animals had metamorphosed. Our results show that exogenous oCRH can accelerate metamorphosis in urodele larvae as it does in anurans. These findings suggest that the neuroendocrine mechanisms controlling metamorphosis are evolutionarily conserved across amphibian taxa. © 2002 Wiley‐Liss, Inc.
Synthesis of [1‐13C]‐para‐xylene and [2‐13C]‐para‐xylene
Authors: Mormann Michael , Kuck Dietmar 
Published: October 2002

AbstractAn efficient synthesis of [1‐13C]‐para‐xylene (1a) and [2‐13C]‐para‐xylene (1b) is described. The incorporation of the label has been achieved by cyclocondensation of suitable 1,5‐bis(bromomagnesio)alkanes with either ethyl [1‐13C]acetate or ethyl [13C]formate which gave [ring‐13C]‐labelled dimethylcyclohexanols. Dehydration of these alcohols followed by dehydrogenation of the intermediate dimethylcyclohexenes furnished the title compounds in 32 and 40% overall yield, respectively. Copyright © 2001 John Wiley & Sons, Ltd.
Ultrastructural observations of eu‐ and paraspermiogenesis in the cottid fish Hemilepidotus gilberti (Teleostei: Scorpaeniformes: Cottidae)
Authors: Hayakawa Youichi , Komaru Akira , Munehara Hiroyuki 
Published: October 2002

AbstractThe developmental process of eu‐ and paraspermatozoa in the cottid fish, Hemilepidotus gilberti, was observed by electron microscopy. Euspermatozoa of H. gilberti consist of a thin disk‐like sperm head (about 3 μm in length), a short middle piece, and a long flagellum, but lack an acrosome. On the other hand, during spermiogenesis, aberrant spermatids, rich in cytoplasm and possessing binuclei, develop into cysts containing spermatids. The developing aberrant spermatids connect with normal spermatids and euspermatozoa by intercellular bridges. The early phase of chromatin condensation in aberrant spermatids is almost identical to that in normal spermatids, but the nuclei in the later phase develop into a mass of highly electron‐dense globules. Since the aberrant spermatids complete karyokinesis but not cytokinesis at telophase of the second meiotic division, they are considered to develop into hyperpyrenic cells due to incomplete cytokinesis of the second meiotic division. These spermatids are oval in shape (5–7 μm in diameter) and lack a flagellum. The aberrant spermatids of H. gilberti are shed along with euspermatozoa and amount to about 50% of semen in volume. Judging from their form and developmental process, aberrant spermatids produced in H. gilberti are considered hyperpyrenic paraspermatozoa. J. Morphol. 253:243–254, 2002. © 2002 Wiley‐Liss, Inc.
Finite element‐based model order reduction of electromagnetic devices
Authors: Zhu Y. , Cangellaris A. C. 
Published: October 2002

AbstractIn this paper an efficient algorithm is presented for the development of compact and passive macro‐models of electromagnetic devices through the systematic reduction of the order of discrete models for these devices obtained through the use of finite elements. The proposed methodology is founded on a new finite element formulation that casts Maxwell's curl equations in a state‐space form. Such state‐space representations are very compatible with a class of robust model order reduction techniques based on Krylov subspaces. However, the advantage of this compatibility appears to be hindered by the fact that the state matrix of the discretized Maxwellian system is of dimension almost twice that obtained from the finite element approximation of the electromagnetic vector wave equation. It is shown in this paper that the apparent penalty in both memory and computation efficiency can be avoided by a proper selection of the finite element expansion functions used for the discretization of the electromagnetic fields. More specifically, it is shown that the proper selection of expansion functions renders the state‐space form of the Maxwellian system equivalent to the discrete problem obtained from the approximation of the vector wave equation using tangentially continuous vector finite elements. This equivalence is then used to effect Krylov‐based model order reduction directly from the finite element approximation of the vector wave equation. In particular, a passive model order reduction algorithm is used for this purpose. The proposed reduced order macro‐modelling algorithm is demonstrated through its application to a variety of microwave passive components. Copyright © 2002 John Wiley & Sons, Ltd.
Analysis of interdigital capacitor and quasi‐lumped miniaturized filters using iterative method
Authors: Gharsallah A. , Gharbi A. , Desclos L. , Baudrand H. 
Published: October 2002

AbstractThis paper presents the application of an iterative method for fast computation of microstrip interdigital capacitor (IDC) and a quasi‐lumped miniaturized filter. The use of a 2D‐FFT algorithm allows simplifications in the calculation process leading to accurate results obtained 20 times faster than in the conventional method cases. Copyright © 2002 John Wiley & Sons, Ltd.
Single‐chain variable fragment antibodies against the neural adhesion molecule CHL1 (close homolog of L1) enhance neurite outgrowth
Authors: Dong Ling , Chen Suzhen , Richter Melanie , Schachner Melitta 
Published: October 2002

AbstractThe neural cell adhesion molecule CHL1 (close homolog of L1) plays important roles in neurite outgrowth and neuronal survival in vitro. Reproducible and functionally active CHL1 antibodies are critical for a better understanding of the functional properties of CHL1 in vitro and in vivo. We have isolated human single‐chain variable fragment (scFv) antibodies against mouse CHL1 from a human synthetic phage display library. To improve the binding activity of such antibodies, a clone (C12) was selected for affinity maturation by combined random mutagenesis of the VH gene and site‐directed cassette mutagenesis to introduce random mutations in the complementarity determining region 3 (CDR3) of the VL gene. From the mutant phage display library, we selected a clone (6C2) that gave the strongest signal as determined by ELISA. The dissociation constant of 6C2 (Kd 2.28 × 10−8 M) was increased approximately 85‐fold compared with the wild‐type clone C12 (Kd 1.93 × 10−6 M). 6C2 detected CHL1 by Western blot analysis in mouse brain homogenates and detected CHL1 in CHL1‐transfected cells by immunofluorescence. Furthermore, the wild‐type and affinity‐matured antibodies promoted neurite outgrowth of hippocampal and cerebellar neurons in vitro. Our results suggest that the affinity‐matured CHL1 scFv antibody will serve a range of applications in vitro and in vivo. © 2002 Wiley‐Liss, Inc.
Chronological changes in pyridoxine‐5′‐phosphate oxidase immunoreactivity in the seizure‐sensitive gerbil hippocampus
Authors: Kang Tae‐Cheon , Park Seung‐Kook , Hwang In Koo , An Sung‐Jin , Bahn Jae Hoon , Kim A. Yeon , Choi Soo Young , Kwon Oh‐Shin , Baek Nam‐In , Lee Hyeon Yong , Won Moo Ho 
Published: October 2002

AbstractTo identify the roles of pyridoxine‐5′‐phosphate (PNP) oxidase in epileptogenesis and the recovery mechanisms in spontaneous seizure, a chronological and comparative analysis of PNP oxidase expression was conducted. PNP oxidase immunoreactivity in a preseizure group of seizure‐sensitive (SS) gerbils was detected more strongly than that in a seizure‐resistant (SR) group. The density of PNP oxidase immunoreactivity in a 30 min postictal group was significantly lower than that in a preseizure group. In a 12 hr postictal group, PNP oxidase immunodensity had recovered to a preseizure level. The overexpression of PNP oxidase in the hippocampus of preseizure SS gerbils suggests that PNP or pyridoxal 5′‐phosphate plays an important role in the modulation of glutamic acid decarboxylase activity and γ‐aminobutyric acid reuptake as mediated by membrane transporter via neurons. In addition, this change in the PNP oxidase immunoreactivity following seizure may be a compensatory response designed to reduce epileptic activity in this animal. © 2002 Wiley‐Liss, Inc.
A daily diary study of affective responses to psychological contract breach and exceeded promises
Authors: Conway Neil , Briner Rob B. 
Published: October 2002

AbstractThe psychological contract has been viewed as an explanatory framework for understanding the employment relationship, and is regarded by some researchers as central in understanding employee attitudes and behavior. Despite the importance ascribed to the psychological contract, it remains theoretically underdeveloped and has received limited empirical attention. This study takes a new approach to researching the psychological contract, through the use of daily diaries, and addresses a number of fundamental questions regarding its nature. Results show that both broken and exceeded promises occur regularly and in relation to virtually any aspect of work, that the importance of the promise contributes significantly to emotional reactions following broken and exceeded promises, and that the psychological contract is an important concept for understanding everyday fluctuations in emotion and daily mood. Copyright © 2002 John Wiley & Sons, Ltd.
Comparison of genuine (1851–1852 AD) and forged or reproduction Hawaiian Missionary stamps using Raman microscopy
Authors: Chaplin Tracey D. , Clark Robin J. H. , Beech David R. 
Published: October 2002

AbstractThe rare and valuable Hawaiian Missionary stamps from the Tapling Collection held at the British Library were analysed using Raman microscopy and shown to be printed with an ink composed of Prussian blue. Blue particles dispersed between the paper fibres of the stamps and present as optical brighteners were identified to be lazurite or the synthetic equivalent, ultramarine blue. Each cancellation or postmark, where present, is composed of carbon, vermilion, iron(III) oxide or a madder‐like organic pigment. The Raman analysis also showed that microscopic repair work on stamps can be identified. The genuine stamps were compared with 13 forged Hawaiian Missionary stamps, printed in the early 20th century, and with a set of eight reproduction items printed in 1985, from the Royal Philatelic Society London. Raman analysis of the forged stamps showed that the ink used is different from that of the genuine stamps, being a mixture of Prussian blue and ultramarine blue, or an organic blue pigment. Analysis of the 1985 reproduction stamps showed that they were printed with modern phthalocyanine blue ink, on paper coated with a yellow organic pigment to simulate aged paper. This analysis provides an invaluable and non‐destructive method for assisting in drawing a distinction between fraudulent or reproduction material and the genuine article. Copyright © 2002 John Wiley & Sons, Ltd.
What is observed in single molecule SERS, and why?
Authors: Otto Andreas 
Published: October 2002

AbstractProposed single molecule surface‐enhanced Raman scattering (SM‐SERS) mechanisms are discussed and problems in SM‐SERS of biological molecules are pointed out. It is unlikely that the single molecule signals can be explained exclusively by electromagnetic (EM) ‘hot spots’ in fractal structures or in narrow gaps. Care must be taken to recognize and avoid the signal of sp2‐carbon contamination, the origins of which are chemical impurities and/or photophysical reactions of the chosen adsorbate. As already pointed out by Käll and co‐workers, relatively large globular proteins fit only in wider gaps, and therefore the EM enhancement is several orders smaller than often reported enhancements in SM‐SERS. SM‐SERS of haemoglobin probably shows signals from the Fe‐porphyrin constituent among other unknown signals. It cannot be excluded that the haemoglobin is denatured and the haem group is situated in a smaller gap. Copyright © 2002 John Wiley & Sons, Ltd.
A study of the quality factors affecting the short‐term decomposition of field vegetable residues
Authors: Rahn C R , Lillywhite R D 
Published: October 2002

AbstractExperiments were carried out to characterise the composition and decomposition of 13 vegetable crop residues. There was a considerable range of composition, with 55% of the dry matter being water‐soluble in onion compared with only 15% in wheat. The range of carbon/nitrogen ratio in the vegetable crops was narrow, between 9 and 24, compared with a C/N ratio of 58 in wheat. The decomposition of the residues could be described by the single‐exponential equationY = a + be−k(t − d), whereYis the proportion of residue remaining at any thermal time day degrees above 0 °C,ais the proportion of residue remaining at the end of the experiment,bis the corresponding proportion of the degradable fraction,kis the rate constant for the decomposition process anddis a delay factor (in units of thermal time) which delays the start of the decomposition process.Y,aandbare all expressed as percentages on a weight basis and, by definition,a + bmust equal 100 att  = 0. The value ofdis assumed to equal zero for all residues except those from leafy brassicas, for which it was set at 100. The half‐life of crop residue decomposition ranged from 145 day deg for onion to over 1400 day deg for wheat. The decomposition rate constant (k) was related to the C and N contents (r  = 0.84,p  = 0.001), and theaparameter to the crop's lignin content (r  = 0.74,p  = 0.004).© 2001 Society of Chemical Industry
Effect of lipid oxidation and frozen storage on muscle proteins of Atlantic mackerel (Scomber scombrus)
Authors: Saeed Suhur , Howell Nazlin K 
Published: October 2002

AbstractThe effect of storage on the lipids and proteins in Atlantic mackerel stored for up to 24 months at −20 and −30 °C was studied. Traditional methods including the peroxide value, thiobarbituric acid‐reactive substances (TBARS) and a reverse phase HPLC method were used to determine the primary and secondary lipid oxidation products. All tests showed an increase in lipid oxidation products with storage time and at a higher storage temperature of −20 °C compared with samples stored at −30 °C. Antioxidants had a significant effect (P < 0.01) on the inhibition of lipid oxidation, as shown by the reduction in peroxide value and hydroxides, and malondialdehyde formation. Similarly, deterioration of protein structure and functionality in mackerel stored for 3, 6, 12 and 24 months was greater at −20 than −30 °C. ATPase activity in the myosin extract of Atlantic mackerel showed a significant decrease (P < 0.01) with progressive frozen storage. Protein solubility in high salt concentration (0.6 M NaCl) decreased (P < 0.01) during storage at both −20 and −30 °C but was greater at −20 °C. Interestingly, antioxidants BHT, vitamin C and vitamin E protected the proteins against complete loss of ATPase activity and protein solubility to a significant level (P < 0.01) for up to 1 year at −20 °C compared with samples stored without antioxidants. This study confirms the deleterious effect of lipid oxidation products on protein structure and function in frozen fatty fish.© 2002 Society of Chemical Industry
The foaming properties of proteins isolated from barley
Authors: Kapp Gregory R , Bamforth Charles W 
Published: October 2002

AbstractAlbumin and hordein protein fractions have been isolated from barley by extraction with salt and aqueous ethanol respectively. Both produce stable foams as assessed by a shaking procedure, and in each case foaming was enhanced by denaturation of the proteins. Foam power was increased rather more for albumin than for hordein, especially by heat, and this was accompanied by an increase in hydrophobic character as assessed by the fluorochrome 1‐anilino‐8‐napthalenesulphonic acid. Iso‐α‐acids and reduced iso‐α‐acids increased the foam stability of both albumin and hordein, with there being a proportionately greater increase for the undenatured proteins. Albumin is resistant to hydrolysis by the cysteine proteinases ficin and papain but is hydrolysed by the serine proteinase trypsin. In the latter instance, hydrolysis is accompanied by a loss of foam stability. By contrast, hordein is resistant to digestion by trypsin but is susceptible to the action of ficin and papain. In these instances, limited proteolysis leads to a substantial enhancement of foam stability from hordein, though prolonged proteolysis is detrimental. Proteinase A from yeast hydrolyses both protein classes and lowers their ability to give stable foams. It is concluded that polypeptides derived from both albumin and hordein could make a contribution to the foam potential of beer.© 2002 Society of Chemical Industry
Non‐destructive texture analysis of farmed Atlantic salmon using visual/near‐infrared reflectance spectroscopy
Authors: Isaksson Tomas , Swensen Lars P , Taylor Richard G , Fjæra Svein O , Skjervold Per O 
Published: October 2002

AbstractFillets of farmed Atlantic salmon were assessed by visual/near‐infrared (VIS/NIR) reflectance spectroscopy, Kramer shear force measurement and texture profile analysis (TPA). Comparison of the Kramer measurements between pairs of subsamples gave correlation coefficients of 0.85 for pre‐rigor (2 h after slaughter), 0.78 for post‐rigor (6 days after slaughter) and 0.97 for pre‐ and post‐rigor combined. TPA gave non‐significant correlations between subsamples. VIS/NIR fibre optic probe measurements gave cross‐validated correlation coefficients for prediction of Kramer shear force of 0.76 for pre‐rigor, 0.68 for post‐rigor and 0.94 for pre‐ and post‐rigor combined. Classification using linear discriminant analysis of the VIS/NIR measurements gave up to 79% correct classification into three categories: low Kramer shear force (2.13 × 10−2–4.41 × 10−2 J g−1), medium Kramer shear force (4.41 × 10−2–6.37 × 10−2 J g−1) and high Kramer shear force (6.37 × 10−2–7.90 × 10−2 J g−1). Using these class limits, no low‐Kramer‐shear‐force sample was misclassified as a high‐Kramer‐shear‐force sample, and vice versa. It can be concluded that non‐destructive VIS/NIR fibre optic probe measurement gives fair predictions of Kramer shear force. Its most useful application in salmon production plants may be to classify fillets into broad classes according to texture before further processing or sale.© 2001 Society of Chemical Industry
The role of the mineral component in surface stabilization processes of a disturbed desert sandy surface
Authors: Yair A. , Verrecchia E. 
Published: October 2002

AbstractThe stabilization of sandy and loamy surfaces in semiarid and arid areas by topsoil crusts protecting the soil against wind or runoff erosion is well known. Destruction of such crusts, often by overgrazing, can enhance erosion and desertification. Crust recovery does not depend purely on biotic components of the crust and vegetation. Mineral components in the initial surface stabilization process are often overlooked. The present study focuses on the relative importance of the biotic and mineral components in the process of topsoil crust recovery in a sandy desert area located in the northwestern Negev Desert of Israel. Observations of the initial crust and of the disturbed surface, in the field and under the scanning electron microscope, showed that the mineral components of the crust recovered more quickly than its biotic elements. The implications for the rehabilitation of the disturbed ecosystem are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Oral bacteria in multi‐species biofilms can be killed by red light in the presence of toluidine blue
Authors: O'Neill John F. , Hope Christopher K. , Wilson Michael 
Published: October 2002

AbstractBackground and ObjectivesOral bacteria can be killed by light in the presence of a suitable photosensitizer, and this could be used in the treatment of oral infections. In these diseases, however, bacteria are present as biofilms, which are refractive to antimicrobial agents. The purpose of this study was to determine whether oral bacterial biofilms were susceptible to lethal photosensitization.Study Design/Materials and MethodsMulti‐species biofilms of oral bacteria were irradiated with light from a helium/neon laser in the presence of toluidine blue O (TBO) and the survivors enumerated. Controls examining the effects of light and TBO alone were also included. The biofilms were also examined by confocal scanning laser microscopy (CSLM).ResultsCSLM revealed that the biofilms had structures similar to those of dental plaque. Although, the biofilms consisted of extremely large numbers of bacteria (∼9 × 109), 97.4% were killed following irradiation with 31.5 J of laser light in the presence of 25 μg/ml TBO.ConclusionsSubstantial numbers of oral bacteria in multi‐species biofilms can be killed by light in the presence of TBO. This may be useful in the treatment of dental plaque‐related diseases. Lasers Surg. Med. 31:86–90, 2002. © 2002 Wiley‐Liss, Inc.