bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies and characterization of RESOL/VAc–EHA/HMMM IPN systems in aqueous medium
Authors: Datta Chandan , Basu Diya , Banerjee Amarnath
Published: October 2002

Resol was solution‐blended with vinyl acetate‐2‐ethylhexyl acrylate (VAc–EHA) resin in an aqueous medium, in varying weight fractions, with hexamethoxymethylmelamine (HMMM) as a crosslinker and the data were compared with a control. The present work was aimed to obtain an optimum combination of high‐temperature resistance by synthesis of an interpenetrating network (IPN) of the resins. The control gave a semi‐IPN system, in which the resol crosslinked, while the acrylic did not, whereas the blend, where HMMM was the crosslinker, gave a full‐IPN system. FTIR spectra of the blends of resol/VAc–EHA/HMMM indicated the formation of new stretching, which was generated due to crosslinking reactions among VAc–EHA and the crosslinker HMMM. TGA showed that, with an increase in the VAc–EHA percent in semi‐IPNs, the decomposition temperature decreased gradually, whereas in case of full‐IPNs, the decomposition temperature increased with increase in the VAc–EHA percent. However, the full‐IPNs had a higher decomposition temperature than that of the semi‐IPNs, at the same resol/(VAc–EHA) ratio. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3581–3588, 2002
Condition monitoring of a thermally aged elastomer by 1H‐NMR T2 relaxation measurements of solvent‐swelled samples
Authors: Assink Roger A. , Celina Mathew , Minier Leanna M.
Published: October 2002

The aging of polymers is often monitored by mechanical property measurements such as those of Young's modulus or tensile elongation at break; new methods are required, however, in situations where traditional mechanical methods cannot be employed. A hydroxy‐terminated polybutadiene/isophorone diisocyanate elastomer is commonly used as a propellant binder. The thermal degradation of the binder is believed to be an important parameter governing the performance of the propellant. Classical mechanical methods cannot be used to monitor the condition of this material when it has been aged in situ as a highly dispersed binder. In this study, the 1H‐NMR spin‐spin relaxation times, T2, of solvent‐swelled samples decreased substantially as thermally induced oxidation led to additional crosslinking. A time–temperature superposition analysis of the relaxation times was performed on samples that had been aged at temperatures ranging from 50 to 125°C. The acceleration factors derived from the relaxation measurements agreed with those reported earlier for tensile elongation at break and oxygen consumption. The dependence of T2 on tensile elongation at break was independent of the temperature at which the sample was aged. A shortened version of the experiment, requiring only two spin‐echo delay times, is presented. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3636–3641, 2002
Syntheses and characterization of blend membranes of sodium alginate and poly(vinyl alcohol) for the pervaporation separation of water + isopropanol mixtures
Authors: Kurkuri Mahaveer D. , Toti Udaya S. , Aminabhavi Tejraj M.
Published: October 2002

The blend membranes of sodium alginate and poly(vinyl alcohol) have been prepared by physical mixing in different ratios (75, 50, and 25%) of sodium alginate with poly(vinyl alcohol). The membranes were crosslinked with glutaraldehyde and used in the pervaporation separation of water + isopropanol mixtures at 30°C. The crosslinking reaction was confirmed by Fourier transform infrared spectra. Permeation flux increased with an increase in mass % of water in the feed mixture as well as with an increase in the amount of poly(vinyl alcohol) in the blend, but separation selectivity decreased. Diffusion coefficients of water + isopropanol mixtures have been calculated using the Fick's equation from the sorption data. Arrhenius activation parameters were calculated for 10 mass % of water in the feed mixture using the values of flux and diffusion coefficients obtained at 30, 40, and 50°C. The diffusion and pervaporation results have been explained on the basis of solution‐diffusion principles. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3642–3651, 2002
The glass transition, crystallization, and melting characteristics of a class of polyester ionomers
Authors: Guo Xian‐Ying , Gu Li‐Xia , Feng Xiao‐Xia
Published: October 2002

The glass transition temperature (Tg), crystallization, and melting character of a class of random polyester ionomers (polymer containing < 10 mol % ionic groups) were investigated. The nonlinear change of theTgand crystallization and melting behavior were characterized using differential scanning colorimetry (DSC). The ionomers are derived from polyethylene terephathalate (PET) modified through copolycondensation with a fully neutralized sulfonate moiety (sodiosulfo) isophthalate (Na‐SIP). Significant and systematic changes in the glass transition temperature and thermal characteristics upon addition of Na‐SIP on the PET backbone were observed, indicating strong association and interaction on the ionic species. At Na‐SIP levels ≥ 4 mol %, the turn of the the glass transition temperature was found, and the same results were obtained for the samples treated either by quenching or dissolution, suggesting the presence of reversible crosslink and aggregation of the ionic species within the organic matrix. When crystallized from the healing or cooling the samples during the DSC nonisothermal crystallization run at a 10°C/min, the enthalpy of the cold crystallization and melting showed an obvious decrease with the increase of Na‐SIP content, and changes of the crystal temperature had an analogy to those of theTg. A tune of the crystal temperature was found at Na‐SIP levels ≥ 3 mol % (see Figs.4,5, and7). The experimental data were discussed in the context of the restricted mobility model of the aggregation in the ionomers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3660–3666, 2002
Immiscible polymer blend electrorheological fluids: Composition dependence
Authors: Orihara Hiroshi , Kawasaki Tomohiko , Doi Masao , Inoue Akio
Published: October 2002

We investigated the composition dependence of the electrorheological properties of immiscible polymer blends which consist of liquid crystalline polymers (LCPs) and polydimethylsiloxane (DMS). We used two different kinds of LCPs, designated as A and B polymers. We observed that for a fixed ratio of an LCP and DMS (LCP:DMS = 2:1) the electrorheological properties change from type I to type II as the fraction of the A polymer is reduced. Microscopic observations indicate that the change in the electrorheological properties is associated with the structural change; in type I, LCP droplets are dispersed in DMS, while in type II, DMS droplets are dispersed and, furthermore, that the structural change is associated with the miscibility between DMS and the LCPs; the A polymer is partially miscible with DMS, while the B polymer is hardly miscible with DMS. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3673–3680, 2002
Copolymerization in UF/pMDI adhesives networks
Authors: Simon C. , George B. , Pizzi A.
Published: October 2002

Kinetic evidence in thermomechanical analysis experiments and carbon‐13 nuclear magnetic resonance spectroscopy (13C NMR) evidence indicates that the strength of a joint bonded with UF (urea–formaldehyde)/polymeric 4,4'‐diphenylmethane diisocyanate (pMDI) glue mixes is improved by coreaction of the methylol groups of UF resins with pMDI to form a certain number of methylene cross‐links. The formation of these methylene cross‐links is predominant, rather than formation of urethane bridges which still appear to form but which are in great minority. This reaction occurs in presence of water and under the predominantly acid hardening conditions, which is characteristic of aminoplastic resins (thus, in presence of a hardener). Coreaction occurs to a much lesser extent under alkaline conditions (hence, without UF resins hardeners). The predominant reaction is then different in UF/pMDI adhesive systems than that observed in phenol‐formaldehyde (PF)/pMDI adhesive systems. The same reaction observed for UF/pMDI system at higher temperatures has also been observed in PF/pMDI systems, but only at lower temperatures. The water introduced in the UF/pMDI mix by addition of the UF resin solution has been shown not to react with pMDI to an extent such as to contribute much, if at all, to the increase in strength of the hardened adhesive. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3681–3688, 2002
Maintenance of mechanical and viscoelastic properties in truck and off‐the‐road tire tread compounds by using 1,3 bis(citraconimidomethyl)benzene
Authors: Datta R. N. , Ingham F. A. A.
Published: October 2002

The effect of the antireversion agent 1,3 bis(citraconimidomethyl)benzene has been studied in a truck compound and a silica containing off‐the‐road compound. Laboratory results show that the antireversion agent significantly improves compound reversion resistance by means of a crosslink compensation mechanism. This improved reversion resistance provides a stabilization of viscoelastic properties on overcure and aging, which in turn should improve the performance of heavy duty tires with regard to rolling resistance and heat buildup throughout their service life. The antireversion agent is particularly effective in stabilizing viscoelastic properties in combination with a reduced level of the saline coupling agent, TESPT. This offers improved tire performance at no cost penalty. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3689–3694, 2002
Study of ionic polymer toughening epoxy resin
Authors: Chen Su‐Chen , Chiu Hsien‐Tang , Ye Chug‐Pin
Published: October 2002

In this study, PEL [copolymer of poly(propylene) oxide (PPO) and poly(ethylene oxide) (PEO)] toughening epoxy resin with ionic charge was used to produce an interpenetrating action between the cross‐linking network structure of the epoxy resin and the PEL additive. Fourier transform infrared (FTIR) analysis of the toughening epoxy resin revealed that NCO disappeared at 2400 cm−1, NH appeared at 3300 cm−1, and CO appeared at 1750 cm−1. These results indicate that a urethane bond was produced. Dynamic mechanical analysis (DMA) and mechanical testing results indicated that as the level of PEL increased, the compatibility between the epoxy resin and PEL also increased. In addition, the compatibility was improved because the addition of cornate hardener produced a graft phenomenon. The tensile property, impact strength, and fracture toughness of PEL toughening epoxy resin all had a tendency to improve. The tensile strength, impact strength, and fracture toughness (KIC value) were most improved when 30 phr cornate was added. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3740–3751, 2002
Identification of a “glycine‐loop”‐like coiled structure in the 34 AA Pro,Gly,Met repeat domain of the biomineral‐associated protein, PM27
Authors: Wustman Brandon A. , Santos Rudolpho , Zhang Bo , Evans John Spencer
Published: October 2002

Fracture resistance in biomineralized structures has been linked to the presence of proteins, some of which possess sequences that are associated with elastic behavior. One such protein superfamily, the Pro,Gly‐rich sea urchin intracrystalline spicule matrix proteins, form protein–protein supramolecular assemblies that modify the microstructure and fracture‐resistant properties of the calcium carbonate mineral phase within embryonic sea urchin spicules and adult sea urchin spines. In this report, we detail the identification of a repetitive keratin‐like “glycine‐loop”‐ or coil‐like structure within the 34‐AA (AA: amino acid) N‐terminal domain, (PGMG)8PG, of the spicule matrix protein, PM27. The identification of this repetitive structural motif was accomplished using two capped model peptides: a 9‐AA sequence, GPGMGPGMG, and a 34‐AA peptide representing the entire motif. Using CD, NMR spectrometry, and molecular dynamics simulated annealing/minimization simulations, we have determined that the 9‐AA model peptide adopts a loop‐like structure at pH 7.4. The structure of the 34‐AA polypeptide resembles a coil structure consisting of repeating loop motifs that do not exhibit long‐range ordering. Given that loop structures have been associated with protein elastic behavior and protein motion, it is plausible that the 34‐AA Pro,Gly,Met repeat sequence motif in PM27 represents a putative elastic or mobile domain. © 2002 Wiley Periodicals, Inc. Biopolymers 65: 362–372, 2002
Ultrastructure of retinal ganglion cell death after axotomy in chick embryos
Authors: Borsello Tiziana , Mottier Vincent , Castagné Vincent , Clarke Peter G.H.
Published: October 2002

Axotomy often leads to neuronal death, which occurs after a particularly short delay in immature animals. Tectal lesions were made in embryonic day (E) 12 chick embryos, thereby axotomizing the retinal ganglion cells of the contralateral eye, which then died within 3 days. We here describe the ultrastructural changes in the axotomized ganglion cells. The main changes were nuclear invagination and type 3B (cytoplasmic type) cell death characterized by dilation of the perinuclear space, endoplasmic reticulum, and Golgi apparatus. However, nuclear invagination was never seen in type 3B dying cells. All the axotomy‐induced retinal ganglion cell death appears to have been of type 3B; apoptosis was not induced by axotomy, as was confirmed by additional light microscopic experiments showing that it did not increase the frequency of apoptotic markers revealed by terminal deoxynucleotidyl transferase‐mediated biotinylated UTP nick end labeling (the TUNEL method) labeling and immunoreactivity for activated caspase‐3. However, the latter methods did show small numbers of apoptotic cells dying naturally even in control retinas. After the death of the axotomized ganglion cells, they were phagocytosed mainly in Müller processes. The present findings open up the chick tectal lesion model as a system for analyzing type 3B neuronal death in vivo. J. Comp. Neurol. 453:361–371, 2002. © 2002 Wiley‐Liss, Inc.
Pituitary adenylate cyclase‐activating peptide in the rat central nervous system: An immunohistochemical and in situ hybridization study
Authors: Hannibal Jens
Published: October 2002

In the present study the localization of pituitary adenylate cyclase‐activating peptide (PACAP)‐expressing cell bodies and PACAP projections were mapped in the adult rat brain and spinal cord by using immunohistochemistry and in situ hybridization histochemistry. A widespread occurrence of PACAP‐containing cell bodies was found, with the greatest accumulation in several hypothalamic nuclei and in several brainstem nuclei, especially the habenular nuclei, the pontine nucleus, the lateral parabrachial nucleus (LPB), and the vagal complex. PACAP was also present in cell bodies in the olfactory areas, in neocortical areas, in the hippocampus, in the vestibulo‐ and cochlear nuclei, in cell bodies of the intermediolateral cell column of the spinal cord and in Purkinje cells of the cerebellum, in the subfornical organ, and in the organum vasculosum of the lamina terminalis. An intense accumulation of PACAP‐immunoreactive (‐IR) nerve fibers was observed throughout the hypothalamus, in the amydaloid and extended amygdaloid complex, in the anterior and paraventricular thalamic nuclei, in the intergeniculate leaflet, in the pretectum, and in several brainstem nuclei, such as the parabrachial nucleus, the sensory trigeminal nucleus, and the nucleus of the solitary tract. PACAP‐IR nerve fibers were also found in the area postrema, the posterior pituitary and the choroid plexus, and the dorsal and ventral horn of the spinal cord. The widespread distribution of PACAP in the brain and spinal cord suggests that PACAP is involved in the control of many autonomic and sensory functions as well as higher cortical processes. J. Comp. Neurol. 453:389–417, 2002. © 2002 Wiley‐Liss, Inc.
Developmental patterns of cadherin expression and localization in relation to compartmentalized thalamocortical terminations in rat barrel cortex
Authors: Gil Orlando D. , Needleman Leigh , Huntley George W.
Published: October 2002

The wiring of synaptic circuitry during development is remarkably precise, but the molecular interactions that enable such precision remain largely to be defined. Cadherins are cell adhesion molecules hypothesized to play roles in axon growth and synaptic targeting during development. We previously showed that N‐cadherin localizes to ventrobasal (VB) thalamocortical synapses in rat somatosensory (barrel) cortex during formation of the whisker‐map in layer IV (Huntley and Benson [1999] J. Comp. Neurol. 407:453–471). Such specific association of N‐cadherin with one identified afferent pathway raises the prediction that other cadherins are expressed in barrel cortex and that these are, in some combination, also differentially associated with distinct inputs. Here, we first show that N‐cadherin and three other classic cadherins (cadherin‐6, ‐8, and ‐10) are expressed contemporaneously in barrel cortex with relative levels of postnatal expression that are highest during the first 2 weeks, when afferent and intrinsic circuitries are forming and synaptogenesis is maximal. Each displayed distinct, but partly overlapping laminar patterns of expression that changed over time. Cadherin‐8 probe hybridization formed a particularly striking pattern of intermittent, columnar patches extending from layer V through layer III, which was first detectable at approximately postnatal day 3. The patches were centered precisely over regions of dysgranular layer IV and, in the whisker barrel field, over barrel septa. This pattern is similar to that formed by the terminal distribution of thalamocortical afferents arising from the posterior nucleus (POm), suggesting cadherin‐8 association with the POm thalamocortical synaptic circuit. Consistent with this, cadherin‐8 mRNAs were enriched in the POm nucleus, and cadherin‐8 immunolabeling in layer IV was enriched in barrel septa and codistributed with labeled POm thalamocortical synaptic‐like puncta. The striking molecular parcellation of at least two different cadherins to the two, converging thalamic pathways that terminated in non‐overlapping barrel center and septal compartments in layer IV strongly suggested that cadherins provide requisite molecular recognition and targeting that enable precise construction of thalamocortical and other synaptic circuitry. J. Comp. Neurol. 453:372–388, 2002. © 2002 Wiley‐Liss, Inc.
Factors influencing periglacial fluvial morphology in the northern European Russian tundra and taiga
Authors: Huisink M. , de Moor J. J. W. , Kasse C. , Virtanen T.
Published: October 2002

The influence of geology, discharge regime, slope, vegetation type, vegetation density and permafrost conditions on periglacial channel morphology has been investigated in the Usa catchment (northern European Russia). Rivers are dominated by meandering or anabranching plan forms and rarely show braiding characteristics, despite a nival discharge regime, the presence of discontinuous permafrost and locally steep slopes.

The dense vegetation cover is an important factor in determining the meandering morphology as it inhibits the sediment supply and hence braided conditions. Differences in vegetation types (taiga in the south, tundra in the north) have no effect on channel plan form. Copyright © 2002 John Wiley & Sons, Ltd.
Road construction and gully erosion in West Pokot, Kenya
Authors: Jungerius P. D. , Matundura J. , van de Ancker J. A. M.
Published: October 2002

The study of soil erosion in Kenya is largely limited to agricultural and pastoral land. Little attention has been given to the effects of roads on soil erosion, although they cause more inconvenience than any other form of soil erosion. The object of this study is the B4, an unpaved road leading from the Marich Pass up the Kerio valley. This road runs across the footslopes of a steep scarp fault, in a climate with torrential rainfall. The footslopes consist of alluvial fans, pediments and terraces. Aerial photographs from 1963 show no erosion along the road: the 162 culverts and drifts were apparently adequate to cope with the drainage of the footslopes. Roadside gully formation is now a big problem for the road engineers.

The 1 km sections of the road marked by the Ministry of Public Works have been used as the units of research, to facilitate exchange of information with the road engineers. In each section of the first 42 km of the road, the volumes of the roadside gullies were measured, along with erosion factors related to type of cross‐drainage construction, stability of the roadside material, geomorphological parameters and decrease in soil cover above the road since 1963. There is a strong correlation between roadside gullies, alluvial fans and decrease of soil cover.

The road engineers were guided by geomorphological principles when designing the road. They preferred drifts, although these dips in the road surface are uncomfortable to pass by car. Drifts resemble natural drainage channels more closely than culverts and cause less damage in the fields below the road. The later settlers also showed geomorphological sense by preferring the smooth surfaces and well drained fine‐grained soils of the alluvial fans.

The research demonstrates a common problem of road design in developing countries: however carefully the measures against erosion are designed, they become rapidly outdated because a new road attracts settlement. Deterioration of surface drainage and erosion start at unforeseeable points where people choose to settle. Copyright © 2002 John Wiley & Sons, Ltd.
Microglia as liaisons between the immune and central nervous systems: Functional implications for multiple sclerosis
Authors: Carson Monica J.
Published: October 2002

Multiple sclerosis is a chronic demyelinating inflammatory disease of the central nervous system (CNS). As the tissue macrophage of the CNS, microglia have the potential to regulate and be regulated by cells of the CNS and by CNS‐infiltrating immune cells. The exquisite sensitivity of microglia to these signals, coupled with their ability to develop a broad range of effector functions, allows the CNS to tailor microglial function for specific physiological needs. However, the great plasticity of microglial responses can also predispose these cells to amplify disproportionately the irrelevant or dysfunctional signals provided by either the CNS or immune systems. The consequences of such an event could be the conversion of self‐limiting inflammatory responses into chronic neurodegeneration and may explain in part the heterogeneous nature of multiple sclerosis. GLIA 40:218–231, 2002. © 2002 Wiley‐Liss, Inc.
Microglia in human immunodeficiency virus‐associated neurodegeneration
Authors: Garden Gwenn A.
Published: October 2002

Infection with the human immunodeficiency virus (HIV) is associated with a syndrome of cognitive and motor abnormalities that may develop in the absence of opportunistic infections. Neurons are not productively infected by HIV. Thus, one hypothesis to explain the pathophysiology of HIV‐associated dementia (HAD) suggests that signals released from other infected cell types in the CNS secondarily lead to neuronal injury. Microglia are the predominant resident CNS cell type productively infected by HIV‐1. Neurologic dysfunction in HAD appears to be a consequence of microglial infection and activation. Several neurotoxic immunomodulatory factors are released from infected and activated microglia, leading to altered neuronal function, synaptic and dendritic degeneration, and eventual neuronal apoptosis. This review summarizes findings from clinical/pathological studies, animal models, and in vitro models of HAD. Most of these studies support the hypothesis that altered microglial physiology is the nidus for a cascade of events leading to neuronal dysfunction and death. Several molecular mediators of neuronal injury in HAD that emanate from microglia have been identified, and strategies for altering the impact of these neurotoxins are discussed. GLIA 40:240–251, 2002. © 2002 Wiley‐Liss, Inc.
The forward rate unbiasedness hypothesis revisited
Authors: Razzak W.A.
Published: October 2002

It is widely accepted that long‐term interest rates are more suitable for testing the Uncovered Interest Rate Parity (UIP) than shorter‐term rates. This paper shows that while using longer‐term (1‐year) forward exchange rates are also more suitable than shorter‐term rates (1‐month) for testing the forward exchange rate unbiasedness hypothesis (FRUH) the test is sensitive to the choice of the numeraire currency, i.e. the US dollar, the Deutsche mark (DM) or the Japanese yen. The FRUH holds in currencies measured in terms of the US dollar when a one‐year forward contract is used instead of a one‐month contract, but it does not hold when the DM and the yen are used as numeraire currencies. Copyright © 2002 John Wiley & Sons, Ltd.
A general equilibrium analysis of foreign direct investment and the real exchange rate
Authors: Shrikhande Milind M.
Published: October 2002

Modern theories of foreign direct investment claim that foreign direct investment occurs because certain domestic assets are worth more under foreign control. This view developed by industrial organization theorists is indifferent to the financing mode of a foreign acquisition as well as to the interaction between foreign direct investment (FDI) and real exchange rates. However, empirical research has uncovered a significant relationship between FDI and exchange rates. Second, partial equilibrium models of FDI have focused on FDI as foreign acquisitions of existing assets but not on new capital formation initiated by foreigners. We complement these contributions by developing a welfare‐maximizing, general equilibrium model of the interaction between FDI as cross‐border acquisitions, and the real exchange rate. Copyright © 2002 John Wiley & Sons, Ltd.
Discrete policy interventions and rational forecast errors in foreign exchange markets: the uncovered interest parity hypothesis revisited
Authors: Kirikos Dimitris G.
Published: October 2002

This paper combines policy response explanations of the uncovered interest parity puzzle with a time series approach that accounts for discrete central bank interventions. When monetary authorities manage the interest rate differential through an anti‐inflationary policy rule, which allows for discrete shifts, then a stochastic segmented trends representation seems appropriate for the exchange rate and the interest rate differential series. In this setting, rational forecast errors are possible, and a test of the uncovered parity hypothesis, based on the cross‐equation restrictions on a Markov switching process, suggests that the parity relationship cannot be rejected for three European currencies vis‐à‐vis the US dollar. Copyright © 2002 John Wiley & Sons, Ltd.
PVC and LDPE for packing minimally processed garlic
Authors: Soares Nilda de Fátima Ferreira , Geraldine Robson M. , Pushmann Rolf , Teles César Silva
Published: October 2002

Minimum processing associated with an adequate packing system has shown good results in preserving a large group of perishable horticultural produce. The present work was done to determine the effect of the number of layered of low‐density polyethylene (LDPE) or polyvinyl chloride (PVC) film on the quality of minimally processed packed garlic (Allium sativum), known for its short shelf‐life. Polystyrene trays containing 200 g garlic bulbils were wrapped in one to four layers of PVC or one or two layers of LDPE and stored at room temperature. Changes in weight, bulbil colouration, in‐package gas composition and apparent quality were monitored for 14 days. Best results were obtained by wrapping the packages in four layers of PVC film, with insignificant weight loss (5%), changes in colour tone and saturation, and the in‐pack atmosphere (O2 = 0.01% and CO2 = 13.5%) inhibited fungal growth, extending shelf‐life to 13 days at 25 ± 2°C. On the other hand, the high in‐package moisture in LDPE wrapping favoured fungal growth, rapidly depreciating bulbil quality. The shelf‐life of minimally processed garlic can be increased by maintaining an adequate in‐pack atmosphere, which can be achieved by using four layers of PVC or a another film of similar permeability. Copyright © 2002 John Wiley & Sons, Ltd.
How the choice of container affects olive oil quality—a review
Authors: Tsimis D. A. , Karakasides N. G.
Published: October 2002

The standardization and packaging of olive oil, as of every edible product, is of decisive importance because it contributes to the preservation of quality at its highest possible level until its consumption. All the parameters involved from production to consumption, e.g. oxygen, light, temperature and transportation, are directly affected by the type of packaging. In this paper, some elements relative to the production and sales of olive oil are presented, followed by a description of the types of packaging (tinplate, plastic) and their influence on olive oil quality. Olive oil is mainly packed in tinplate and plastic containers. Tinplate containers, because of their advantages, still remain the best container type for edible oil packaging. Plastics, even though they have major advantages, e.g. their low price and low weight, have a negative environmental effect after their disposal and that seems to define their future. Copyright © 2002 John Wiley & Sons, Ltd.
Random dyadic tilings of the unit square
Authors: Janson Svante , Randall Dana , Spencer Joel
Published: October 2002

A “dyadic rectangle” is a set of the formR= [a2−s, (a+ 1)2−s] × [b2−t, (b+ 1)2−t], wheresandtare nonnegative integers. A dyadic tiling is a tiling of the unit square with dyadic rectangles. In this paper we studyn‐tilings, which consist of 2nnonoverlapping dyadic rectangles, each of area 2−n, whose union is the unit square. We discuss some of the underlying combinatorial structures, provide some efficient methods for uniformly sampling from the set ofn‐tilings, and study some limiting properties of random tilings. © 2002 Wiley Periodicals, Inc. Random Struct. Alg., 21: 225–251, 2002
On the discrepancy of combinatorial rectangles
Authors: Alon Noga , Doerr Benjamin , Łuczak Tomasz , Schoen Tomasz
Published: October 2002

Let ℬ︁ denote the family which consists of all subsets S1 × … × Sd, where Si ⊆ [n], and Si ≠ ∅︁, for i = 1, … , d. We compute the L2‐discrepancy of ℬ︁ and give estimates for the Lp‐discrepancy of ℬ︁ for 1 ≤ p ≤ ∞.© 2002 Wiley Periodicals, Inc. Random Struct. Alg., 21: 205–215, 2002
Problems and results on judicious partitions
Authors: Bollobás B. , Scott A. D.
Published: October 2002

We present a few results and a larger number of questions concerning partitions of graphs or hypergraphs, where the objective is to maximize or minimize several quantities simultaneously. We consider a variety of extremal problems; many of these also have algorithmic counterparts. © 2002 Wiley Periodicals, Inc. Random Struct. Alg., 21: 414–430, 2002
Augmenting panoramas with object movies by generating novel views with disparity‐based view morphing
Authors: Hung Yi‐Ping , Chen Chu‐Song , Tsai Yu‐Pao , Lin Szu‐Wei
Published: October 2002

Our goal is to augment a panorama with object movies in a visually 3D‐consistent way. Notice that a panorama is recorded as one single 2D image and an object movie (OM) is composed of a set of 2D images taken around a 3D object. The challenge is how to integrate the above two sources of 2D images in a 3D‐consistent way so that the user can easily manipulate object movies in a panorama. To solve this problem, we adopt a purely image‐based approach that does not have to reconstruct the geometric models of the 3D objects to be inserted in the panorama. A critical issue of this method is how to generate the novel views required for showing an OM in different places of a panorama, and we have proposed a view morphing technique, called t‐DBVM, to solve this problem. Our experiments have shown that this purely image‐based approach can effectively generate visually convincing OM‐augmented panoramas. This method has great potential for many applications that require integration of panoramas and object movies, such as virtual malls, virtual museum, and interior design. Copyright © 2002 John Wiley & Sons, Ltd.
Layered lumigraph with LOD control
Authors: Tong Xin , Chai Jinxiang , Shum Heung‐Yeung
Published: October 2002

The rendering performance of an image‐based rendering (IBR) system is determined by the number of images and the amount of geometrical information used. In this paper, we propose a layered lumigraph representation that is configured for optimized rendering performance based on the rendering platform (e.g., processor speed, memory) and output image resolution. The layered lumigraph is produced by classifying all pixels into a number of depth layers. Based on prior work on plenoptic sampling analysis, the layered lumigraph is constructed to achieve the same rendering quality along the minimum sampling curve by balancing the number of images and depth layers. For a given rendering platform, the best rendering performance can be obtained by choosing the optimal number of images and depth layers. Moreover, the layered lumigraph is capable of level‐of‐detail (LOD) control using the same image geometry trade‐off. Therefore, the layered lumigraph fully exploits the inherent constraints between the number of images, depth complexity, and output resolution. Finally, a backward warping technique is designed to efficiently render the layered lumigraph by taking advantage of texture mapping hardware. Copyright © 2002 John Wiley & Sons, Ltd.
Biological effects of group IIA secreted phosholipase A2
Authors: Fuentes Lucı́a , Hernández Marita , Nieto Marı́a Luisa , Sánchez Crespo Mariano
Published: October 2002

Group IIA secreted phospholipase A2 (sPLA2‐IIA) is the most abundant element in human tissues of a large family of low molecular weight phospholipases A2, which shows properties different from those displayed by the cytosolic phospholipase A2 involved in the release of arachidonic acid. sPLA2‐IIA behaves as a ligand for a group of receptors inside the C‐type multilectin mannose receptor family and also interacts with heparan sulfate proteoglycans such as glypican, the dermatan/chondroitin sulfate‐rich decorin, and the chondroitin sulfate‐rich versican, thus being able to internalize to specific compartments within the cell and producing biological responses. This review provides a short summary of the biological actions of sPLA2‐IIA on intracellular signaling pathways.
The structure of phosphatidylinositol transfer protein α reveals sites for phospholipid binding and membrane association with major implications for its function
Authors: van Tiel Claudia M , Schouten Arie , Snoek Gerry T , Gros Piet , Wirtz Karel W.A
Published: October 2002

Elucidation of the three‐dimensional structure of phosphatidylinositol transfer protein α (PI‐TPα) void of phospholipid revealed a site of membrane association connected to a channel for phospholipid binding. Near the top of the channel specific binding sites for the phosphorylcholine and phosphorylinositol head groups were identified. The structure of this open form suggests a mechanism by which PI‐TPα preferentially binds PI from a membrane interface. Modeling predicts that upon association of PI‐TPα with the membrane the inositol moiety of bound PI is accessible from the medium. Upon release from the membrane PI‐TPα adopts a closed structure with the phospholipid bound fully encapsulated. This structure provides new insights as to how PI‐TPα may play a role in PI metabolism.
Embryonic brain expression analysis of lysophospholipid receptor genes suggests roles for s1p1 in neurogenesis and s1p1–3 in angiogenesis
Authors: McGiffert Christine , Contos James J.A , Friedman Beth , Chun Jerold
Published: October 2002

In a comparison of embryonic brain expression patterns of lysophosphatidic acid and sphingosine 1‐phosphate receptor genes (lpa1–3
and s1p1–5
, respectively), transcripts detected by Northern blot were subsequently localized using in situ hybridization. We found striking s1p1
expression adjacent to several ventricles. Near the lateral ventricle, s1p1
expression was temporally and spatially coincident with neurogenesis and overlapped with lpa1
in the neocortical area. We also observed a widespread diffuse pattern for lpa2–3
and a scattered punctate pattern for s1p1–3
. The punctate pattern colocalized with vascular endothelial markers. Together, these results suggest that s1p1
influences neurogenesis and s1p1–3
influence angiogenesis in the developing brain.
Regulation of phospholipase D
Authors: Exton John H
Published: October 2002

Structural studies of plant and bacterial members of the phospholipase D (PLD) superfamily are providing information about the role of the conserved HKD domains in the structure of the catalytic center and the catalytic mechanism of mammalian PLD isozymes (PLD1 and PLD2). Mutagenesis and sequence comparison studies have also defined the presence of pleckstrin homology and phox homology domains in the N‐terminus and have demonstrated that a conserved sequence at the C‐terminus is required for catalysis. The N‐ and C‐terminal regions of PLD1 also contain interaction sites for protein kinase C, which can directly activate the enzyme through a non‐phosphorylating mechanism. Small G proteins of the Rho and ADP‐ribosylation factor families also directly regulate the enzyme, with RhoA binding to a sequence in the C‐terminus. Certain tyrosine kinases and members of the Ras subfamily of small G proteins can activate the enzyme, but the mechanisms appear to be indirect. The mechanisms by which agonists activate PLD in vivo probably involve multiple pathways.
Membrane properties of sphingomyelins
Authors: Ramstedt Bodil , Slotte J.Peter
Published: October 2002

Sphingomyelin and phosphatidylcholine are important components in the external leaflet of cellular plasma membranes. In this review we compare the structure of these lipid molecules, with emphasis on the differences in hydrogen bonding capacity and membrane properties that arise from the small but significant differences in molecular structure. The membrane properties of sphingomyelins and the implications that these have, or might have, in biological membranes and for raft function are further discussed.
Role of caspases in TNF‐mediated regulation of cPLA2
Authors: Krönke Martin , Adam-Klages Sabine
Published: October 2002

A major part of the proinflammatory activity of tumor necrosis factor (TNF) is brought about by cytosolic phospholipase A2 (cPLA2) that generates arachidonic acid, the precursor for the production of leukotrienes and prostaglandins. The activation of cPLA2 and induction of proinflammatory lipid mediators is in striking contrast to the teleologic meaning of apoptosis, which is to avoid an inflammatory reaction. In this review we highlight the evidence for a caspase‐mediated cleavage and inactivation of cPLA2, which seems to be an important mechanism by which TNF downregulates cPLA2 activity in cells undergoing apoptosis.
Tandem genomic arrangement of a G protein (Gna15) and G protein‐coupled receptor (s1p4/lpC1/Edg6) gene
Authors: Contos James J.A , Ye Xiaoqin , Sah Valerie P , Chun Jerold
Published: October 2002

A genomic analysis of the s1p4
/lpC1
/Edg6 mouse sphingosine‐1‐phosphate (S1P) G protein‐coupled receptor gene revealed it to be located on central chromosome 10 and to consist of two exons with an intronless coding region. Surprisingly, we found the gene encoding the promiscuously coupling Gα15 protein (Gna15) located in tandem just upstream, an arrangement conserved in the human genome (on chromosome 19p13.3). Given that Northern blots demonstrated similar tissue distributions of the mouse s1p4
and Gna15 transcripts, we propose that transcription of the two genes may be under control of the same enhancer elements and that their protein products may couple in vivo.
Phospholipase A2 regulation of arachidonic acid mobilization
Authors: Balsinde Jesús , Winstead Michelle V , Dennis Edward A
Published: October 2002

Phospholipase A2 (PLA2) constitutes a growing superfamily of lipolytic enzymes, and to date, at least 19 distinct enzymes have been found in mammals. This class of enzymes has attracted considerable interest as a pharmacological target in view of its role in lipid signaling and its involvement in a variety of inflammatory conditions. PLA2s hydrolyze the sn‐2 ester bond of cellular phospholipids, producing a free fatty acid and a lysophospholipid, both of which are lipid signaling molecules. The free fatty acid produced is frequently arachidonic acid (AA, 5,8,11,14‐eicosatetraenoic acid), the precursor of the eicosanoid family of potent inflammatory mediators that includes prostaglandins, thromboxanes, leukotrienes and lipoxins. Multiple PLA2 enzymes are active within and surrounding the cell and these enzymes have distinct, but interconnected roles in AA release.
Glycosphingolipid‐dependent cross‐talk between glycosynapses interfacing tumor cells with their host cells: essential basis to define tumor malignancy
Authors: Hakomori Senitiroh , Handa Kazuko
Published: October 2002

Status of tumor progression (either remaining in situ, or becoming invasive/metastatic) may be defined largely by subtle interactions (‘cross‐talk’) in a microenvironment formed by interfacing tumor cell and host cell membrane domains (termed ‘glycosynapses’) involved in glycosylation‐dependent cell adhesion and signaling. Functional roles of tumor‐associated gangliosides, organized in glycosynapses of three types of tumor cell lines, are discussed. Gangliosides function as adhesion receptors or as ‘sensors’ that can be stimulated by antibodies, with consequent activation of signal transducers leading to enhanced motility and invasiveness.
Sphingosine‐1‐phosphate: dual messenger functions
Authors: Payne Shawn G , Milstien Sheldon , Spiegel Sarah
Published: October 2002

The sphingolipid metabolite sphingosine‐1‐phosphate (S1P) is a serum‐borne lipid that regulates many vital cellular processes. S1P is the ligand of a family of five specific G protein‐coupled receptors that are differentially expressed in different tissues and regulate diverse cellular actions. Much less is known of the intracellular actions of S1P. It has been suggested that S1P may also function as an intracellular second messenger to regulate calcium mobilization, cell growth and suppression of apoptosis in response to a variety of extracellular stimuli. Dissecting the dual actions and identification of intracellular targets of S1P has been challenging, but there is ample evidence to suggest that the balance between S1P and ceramide and/or sphingosine levels in cells is an important determinant of cell fate.
Tibolone versus four estrogen replacement therapy protocols and plasma lipid levels in postmenopausal women
Authors: Cetinkaya M.B. , Alper T. , Kokcu A. , Yanik F.F. , Malatyalioglu E.
Published: October 2002

Objectives: To compare tibolone therapy with four different estrogen replacement therapy protocols, with regard to the effects on plasma lipid profiles. Methods: The plasma lipid levels of 178 postmenopausal women in five different therapy groups were compared with each other as well as their baseline levels with 6‐month intervals during 2‐year follow‐up. Student's t‐test, paired t‐test and Pearson correlation analysis were utilized for statistical analysis. Results: HDL cholesterol levels increased significantly from baseline in groups using oral estrogen (P<0.05) but a slight non‐significant decrease was seen in tibolone therapy (P>0.05). LDL cholesterol levels significantly decreased at the end of the second year in oral estrogen and tibolone users (P<0.05). Triglyceride levels increased non‐significantly with estrogen therapy (P>0.05), whilst decreased significantly in the tibolone group (P<0.05). Conclusion: Tibolone may be a good alternative to estrogen replacement therapy in postmenopausal women, as it has beneficial effects on LDL cholesterol and triglyceride levels, which play important role in atherosclerosis.
Low use of medication in home deliveries in the Netherlands
Authors: Schirm E. , Tobi H. , de Jong‐van den Berg L.T.W.
Published: October 2002

Objectives: In view of the growing concern for de‐medicalizing childbirth, the aim of this study is to give detailed figures on the use of medication during home deliveries in the Netherlands. Methods: A prospective study of medication use by 68 community midwives during 716 home births in the Netherlands. Results: Medication was used in 58.4% of the home deliveries, with an average of 1.4 drugs per delivery. The drugs used were mostly oxytocin (in 35.6% of all deliveries) and local anesthetics (in 32.9%). When medication was used, it was administered before cutting the umbilical cord in 16.7% of the cases. Prophylactic or routine administration of local anesthesia, postpartum hemorrhages, and retained placenta were the most frequent indications for using medication. Conclusions: The use of medication during home deliveries in the Netherlands is low and newborns are minimally exposed to medication. This illustrates the Dutch birth culture, which tends to minimize the medical aspect of childbirth.
Three‐dimensional ultrasound in prenatal counselling of congenital talipes equinovarus
Authors: Mohammed N.B , Biswas A
Published: October 2002

The fetus of a 35‐year‐old woman, gravida 5, para 3, was diagnosed with isolated left‐sided congenital talipes equinovarus on routine ultrasound at 22 weeks of gestation. Parents were counselled about the abnormality but still ultrasound pictures made it difficult for them to understand the nature of the defect. A three‐dimensional ultrasound scan helped the couple to understand the abnormality, make an informed choice—with self‐confidence—regarding pregnancy continuation, and plan for postnatal management.
Uterine artery embolization for the treatment of uterine leiomyomata
Authors: Messina M.L. , Bozzini N. , Halbe H.W. , Pinotti J.A.
Published: October 2002

Objectives: To evaluate the results of the uterine artery embolization (UAE) for the treatment of uterine fibroids. Methods: Twenty‐six patients with ultrasonographic diagnosis of uterine leiomyomata were submitted to UAE with polyvinyl alcohol particles. Imaging and clinical follow‐up was performed before the procedure, at 3 months, and 1 year after. Results: All procedures but one were technically successful. Control of menorrhagia and pelvic pain were reported after UAE by 87.5% and 84.2% of patients, respectively. The initial medium uterine volume was 385 cm3, after 3 months 255 cm3 and after 1 year 202 cm3. The mean uterine volume decrease was 29% after 3 months and 41% after 1 year of follow‐up (P<0.001). Clinical and biochemical findings consistent with ovarian failure were observed in three patients (12% of the patients). Conclusions: UAE represents a new therapeutic approach in the treatment of uterine leiomyomata. The procedure appears effective in controlling symptoms and represents an alternative to hysterectomy.