bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional differentiation within the medial temporal lobe in the rat
Authors: Jarrard Leonard E. , Davidson Terry L. , Bowring Beverly
Published: April 2004

The structures that comprise the medial temporal lobe (MTL) have been implicated in learning and memory. The question of primary concern in the present research was whether the group of anatomically related structures (hippocampus, subiculum, presubiculum/parasubiculum, entorhinal cortex, perirhinal/postrhinal cortex) are involved in mediating a similar memory process or whether the individual structures are differentially involved in memory processes and/or in handling various types of information. A series of five experiments were carried out that involved selectively lesioning the main MTL structures and testing each animal on radial‐maze tasks and procedures that provided measures of two different memory processes (reference memory, working memory) and the utilization of two kinds of information (spatial, nonspatial). The structures were found to differ functionally, with the hippocampus and the presubiculum/parasubiculum being especially involved in processing spatial information, and the perirhinal/postrhinal cortex having a specific role in remembering information over a brief time period (working memory). Lesions of the entorhinal cortex failed to affect consistently either memory process or type of information handled, but they did result in impairments in learning the complex spatial discrimination requiring reference memory and in working memory involving nonspatial information. The pattern of behavioral impairments resulting from damage to these discrete MTL structures suggests that several of the structures make unique contributions to learning and memory. © 2004 Wiley‐Liss, Inc.
Associative recognition in a patient with selective hippocampal lesions and relatively normal item recognition
Authors: Mayes A.R. , Holdstock J.S. , Isaac C.L. , Montaldi D. , Grigor J. , Gummer A. , Cariga P. , Downes J.J. , Tsivilis D. , Gaffan D. , Gong Qiyong , Norman K.A.
Published: April 2004

Previous work (Mayes et al., Hippocampus 12:325–340, 2002) found that patient YR, who suffered a selective bilateral lesion to the hippocampus in 1986, showed relatively preserved verbal and visual item recognition memory in the face of clearly impaired verbal and visual recall. In this study, we found that YR's Yes/No as well as forced‐choice recognition of both intra‐item associations and associations between items of the same kind was as well preserved as her item recognition memory. In contrast, YR was clearly impaired, and more so than she was on the above kinds of recognition, at recognition of associations between different kinds of information. Thus, her recognition memory for associations between objects and their locations, words and their temporal positions, abstract visual items or words and their temporal order, animal pictures and names of professions, faces and voices, faces and spoken names, words and definitions, and pictures and sounds, was clearly impaired. Several of the different information associative recognition tests at which YR was impaired could be compared with related item or inter‐item association recognition tests of similar difficulty that she performed relatively normally around the same time. It is suggested that YR's familiarity memory for items, intra‐item associations, and associations between items of the same kind was mediated by her intact medial temporal lobe cortices and was preserved, whereas her hippocampally mediated recall/recollection of these kinds of information was impaired. It is also suggested that the components of associations between different kinds of information are represented in distinct neocortical regions and that initially they only converge for memory processing within the hippocampus. No familiarity memory may exist in normal subjects for such associations, and, if so, YR's often chance recognition occurred because of her severe recall/recollection deficit. Conflicting data and views are discussed, and the way in which recall as well as item and associative recognition need to be systematically explored in patients with apparently selective hippocampal lesions, in order to resolve existing conflicts, is outlined. © 2004 Wiley‐Liss, Inc.
Selection correction and sensitivity analysis for ordered treatment effect on count response
Authors: Lee Myoung‐Jae
Published: April 2004

In estimating the effect of an ordered treatment τ on a count responseywith an observational data where τ is self‐selected (not randomized), observed variablesxand unobserved variables ε can be unbalanced across the control group (τ = 0) and the treatment groups (τ = 1, …,J). While the imbalance inxcauses ‘overt bias’ which can be removed by controlling forx, the imbalance in ε causes ‘covert (hidden or selection) bias’ which cannot be easily removed. This paper makes three contributions. First, a proper counter‐factual causal framework for ordered treatment effect on count response is set up. Second, with no plausible instrument available for τ, a selection correction approach is proposed for the hidden bias. Third, a nonparametric sensitivity analysis is proposed where the treatment effect is nonparametrically estimated under no hidden bias first, and then a sensitivity analysis is conducted to see how sensitive the nonparametric estimate is to the assumption of no hidden bias. The analytic framework is applied to data from the Health and Retirement Study: the treatment is ordered exercise levels in five categories and the response is doctor office visits per year. The selection correction approach yields very large effects, which are however ruled out by the nonparametric sensitivity analysis. This finding suggests a good deal of caution in using selection correction approaches. Copyright © 2004 John Wiley & Sons, Ltd.
Learning about heterogeneity in returns to schooling
Authors: Koop Gary , Tobias Justin L.
Published: April 2004

Using data from the National Longitudinal Survey of Youth (NLSY) we introduce and estimate various Bayesian hierarchical models that investigate the nature of unobserved heterogeneity in returns to schooling. We consider a variety of possible forms for the heterogeneity, some motivated by previous theoretical and empirical work and some new ones, and let the data decide among the competing specifications. Empirical results indicate that heterogeneity is present in returns to education. Furthermore, we find strong evidence that the heterogeneity follows a continuous rather than a discrete distribution, and that bivariate normality provides a very reasonable description of individual‐level heterogeneity in intercepts and returns to schooling. Copyright © 2004 John Wiley & Sons, Ltd.
Why were changes in the federal funds rate smaller in the 1990s?
Authors: Basistha Arabinda , Startz Richard
Published: April 2004

We identify two major changes in the dynamics of the federal funds rate in the 1990s. We model the desired rate in a two‐regime setting, one when the Fed makes no change and the other when the Fed is moving the desired rate to a new level. We find that the 1990s saw a longer duration in the no‐change regime as well as smaller changes in the other regime. The smaller changes were neither due to a less aggressive Fed nor due to lower volatility of the fundamentals. In fact, the Fed responded more aggressively to changes in fundamentals in the 1990s. Copyright © 2004 John Wiley & Sons, Ltd.
Micropatterned surfaces prepared using a liquid crystal projector‐modified photopolymerization device and microfluidics
Authors: Itoga Kazuyoshi , Yamato Masayuki , Kobayashi Jun , Kikuchi Akihiko , Okano Teruo
Published: April 2004

A commercial liquid crystal device projector was modified for photopolymerization using its on‐board intense light source and a precision optical control circuit. This device projects reduced images generated by a typical personal computer onto the stage where photopolymerization on a surface occurs. This all‐in‐one device does not require expensive photomasks and external light sources. However, light scattering and diffraction through glass substrates resulted in undesired reactions in areas corresponding to masked (black) domains in mask patterns, limiting pattern resolution. To overcome this shortcoming, two‐step surface patterning was developed. First, three‐dimensional microstructures of crosslinked silicone elastomer were fabricated with this device and adhered onto silanized glass substrate surfaces, forming microchannels in patterns on the glass support. Then, acrylamide monomer solution containing photoreactive initiator was flowed into these micromold channels and reacted in situ. The resultant polyacrylamide layer was highly hydrophilic and repelled protein adsorption. Cell seeding on these patterns in serum‐supplemented culture medium produced cells selectively adhered to different patterns: cells attached and spread only on unpolymerized silanized glass surfaces, not on the photopolymerized acrylamide surfaces. This technique should prove useful for inexpensive, rapid prototyping of surface micropatterns from polymer materials. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 391–397, 2004
An interactive‐synergetic approach to the assessment of personality vulnerability to depression: Illustration using the adolescent version of the Depressive Experiences Questionnaire
Authors: Shahar Golan , Gallagher Elizabeth F. , Blatt Sidney J. , Kuperminc Gabriel P. , Leadbeater Bonnie J.
Published: April 2004

Research on personality vulnerability to depression is characterized by a “main effect” approach, often at the expense of examining interactions among various dimensions of vulnerability. To compare the “main effect” and “interactive‐synergetic” approaches, we utilized data from a longitudinal study of adolescent adjustment. Focusing on dependency, self‐criticism, and efficacy, the three factors of the adolescent version of the Depressive Experiences Questionnaire (DEQ; Blatt, Schaffer, Bers, & Quinlan, 1992), we found support for the interactive‐synergetic approach. Dependency and self‐criticism interacted in predicting changes in depressive and internalizing symptoms (under low efficacy), and among boys—changes in internalizing and externalizing symptoms. Results illuminate the synergetic interplay among dimensions of risk and resilience in clinical research and practice. © 2004 Wiley Periodicals, Inc. J Clin Psychol.
Visualising bioprocesses using ‘3D‐Windows of Operation’
Authors: King Josh MP , Griffiths Paul , Zhou Yuhong , Titchener‐Hooker Nigel J
Published: April 2004

The operation of bioprocesses involves handling many variables with complex interactions. The visualisation of interactions is vital if suitable conclusions are to be drawn. This paper extends the previously developed ‘Windows of Operation’ to three dimensions, enabling the effects of three parameters to be visualised simultaneously. A tool with a graphical user interface has been developed to enable the generation of ‘3D‐Windows of Operation’ and the visualisation of the effects of the variation of any three control variables. Its use is illustrated with simulations of enzyme production. A number of control variables and the effects of the imposition of constraints on the range of possible operating values are investigated. Changes in the range possible are related to the variation in specific constraints or variables. Finally, it is illustrated how these diagrams and operation heuristics may be used to select suitable operating conditions for the bioprocess. Copyright © 2004 Society of Chemical Industry
Anaerobic biodegradation of phenol in sulfide‐rich media
Authors: Olguín‐Lora Patricia , Razo‐Flores Elías
Published: April 2004

In the refinery industry, the washing processes of middle‐distillates using caustic solutions generate phenol‐ and sulfide‐containing waste streams. The spent caustic liquors generated contain phenols at concentrations higher than 60 g dm−3(638.3 mmol dm−3). For sulfur compounds, the average sulfide concentration was 48 g dm−3(1500 mmol dm−3) in these streams. The goal of this study was to evaluate the specific impact of phenol and sulfide concentrations towards the phenol‐biodegradation activity of a phenol‐acclimated anaerobic granular sludge. An inhibition model was used to calculate the phenol and sulfide inhibitory concentrations that completely stopped the phenol‐biodegradation activity (IC100). A maximum phenol‐biodegradation activity of 83 µmol g−1 VSS h−1 was assessed and the IC100 values were 21.8 mmol dm−3 and 13.4 mmol dm−3 for phenol and sulfide respectively. The limitation of the phenol biodegradation flow by phenol inhibition seemed to be related to the more important sensitivity of phenol‐degrading bacteria. The up‐flow anaerobic sludge bed reactor operating in a non‐phenol‐dependent inhibition condition did not present any sensitivity to sulfide concentrations below 9.6 mmol dm−3. At this residual concentration, the pH and bisulfide ions' concentration might be responsible for the general collapsing of the reactor activity. Copyright © 2004 Society of Chemical Industry
A model for non‐viral gene delivery: through syndecan adhesion molecules and powered by actin
Authors: Kopatz Idit , Remy Jean‐Serge , Behr Jean‐Paul
Published: April 2004

Background

Cell transfection requires cationic DNA complexes and heparan sulfate proteoglycans (HSPGs) at the cell surface. Syndecans are transmembrane HSPGs that are ubiquitously expressed on adherent cells. Their polyanionic heparan sulfate moieties are bound at the distal end of their ectodomain, thus facilitating interaction with large cationic particles.

Methods

We propose a model for cell entry involving syndecans as receptors for the DNA complexes by comparing transfection with bacteria uptake and using drug inhibition experiments along with confocal microscopy.

Results

When combined with results from the literature, our data suggest the following sequence of events: after initial particle binding, gradual electrostatic zippering of the plasma membrane onto the particle is sustained by lateral diffusion of syndecan molecules that cluster into cholesterol‐rich rafts. Clustering in turn triggers PKC activity and linker protein‐mediated actin binding to the cytoplasmic tail of the syndecans. Resulting tension fibers and a growing network of cortical actin may then pull the particle into the cell.

Conclusions

Diversion of integrin‐ and syndecan‐mediated cell adhesion processes for particle engulfment appears to be widely exploited by animals (chylomicrons), by pathogens (bacteria, viruses) and, as suggested here, by non‐viral vectors. Copyright © 2004 John Wiley & Sons, Ltd.
Adenoviral gene transfer to the neonatal rat pulmonary circulation
Authors: West James , Buchholz Mark , Fiero Allan , Tada Yuji , Fagan Karen , Rodman David
Published: April 2004

Background

Gene delivery to the pulmonary circulation has been studied in adult animals, but has not been extensively investigated in neonates.

Methods

We tested the ability of recombinant, replication‐defective adenovirus to transduce the pulmonary circulation when delivered by percutaneous ventricular puncture. Five‐day‐old rat pups were injected with 107 to 1010 particles (approximately 105 to 108 pfu) in 30 µl total volume.

Results

Using RT‐PCR, we detected transgene expression in both lung and liver at all dosages. However, whereas only 1/6 pups injected with 107 particles had detectable expression, 8/9 pups in the two highest dose groups had detectable expression. In the highest dose group expression was approximately 5‐fold greater in lung than liver, though in the lower dose groups no difference between lung and liver was found. Expression decreased by only 25% from day 4 through the last time point at day 28 in lung, whereas liver expression was undetectable in 7 of 9 samples on day 28. Histopathological examination demonstrated expression both within the media of large arteries and in small, peripheral arteries and capillaries, with a concentration of expression in the most distal areas of both the lungs and liver. No evidence of inflammation was seen.

Conclusions

We conclude that the neonatal pulmonary circulation can be effectively transduced using systemic adenoviral vector injection, has more sustained expression than liver, and may be a target for therapeutic gene delivery. Copyright © 2004 John Wiley & Sons, Ltd.
The circular chromatic number of a digraph
Authors: Bokal Drago , Fijavz Gas̆per , Juvan Martin , Kayll P. Mark , Mohar Bojan
Published: April 2004

We introduce the circular chromatic number χc of a digraph and establish various basic results. They show that the coloring theory for digraphs is similar to the coloring theory for undirected graphs when independent sets of vertices are replaced by acyclic sets. Since the directed k‐cycle has circular chromatic number k/(k – 1), for k ≥ 2, values of χc between 1 and 2 are possible. We show that in fact, χc takes on all rational values greater than 1. Furthermore, there exist digraphs of arbitrarily large digirth and circular chromatic number. It is NP‐complete to decide if a given digraph has χc at most 2. © 2004 Wiley Periodicals, Inc. J Graph Theory 46: 227–240, 2004
Gas phase production of [11C]methyl iodide‐d3. Synthesis and biological evaluation of S‐[N‐methyl‐11C]citalopram and deuterated analogues
Authors: Madsen Jacob , Elfving Betina , Andersen Kim , Martiny Lars , Knudsen Gitte M.
Published: April 2004

Three 11C‐labelled tracers for the serotonin reuptake site, S‐[N‐methyl‐11C]citalopram ([11C]‐4), S‐[N‐methyl‐d3‐11C]citalopram ([11C]‐12), and S‐[N‐methyl‐11C]citalopram‐α,α‐d2 ([11C]‐13) were synthesized and the distribution of radioactivity after injection of radioligand was examined ex vivo in rats. The deuterated analogue of (S)‐desmethylcitalopram, (S)‐1‐(4‐fluorophenyl)‐1‐(3‐methylamino‐[3‐d2]‐propyl)‐1,3‐di‐hydro‐isobenzofuran‐5‐carbonitrile (11), was synthesized in a multi‐step synthesis from escitalopram (4) and used as precursor in the synthesis of [11C]‐13. In analogy with the reported gas phase synthesis of [11C]methyl iodide the first gas phase synthesis of [11C]Methyl iodide‐d3 is reported. The 1H/2H kinetic isotope effect related to the synthesized compounds were investigated in ex vivo rat studies, where the brain regions of interest to cerebellum ratios of the tracers [11C]‐4, [11C]‐12 and [11C]‐13 were compared. The ex vivo data indicated no significant differences in binding in any of the investigated brain regions after injection of the three tracers. Copyright © 2004 John Wiley & Sons, Ltd.
Syntheses of carbon‐14 labelled AJ‐9677, a specific β3‐adrenoceptor agonist
Authors: Ochi Takeshi , Toda Hiroshi , Minamida Akira , Terauchi Yoshiaki , Fujii Toshihiko
Published: April 2004

Two 14C‐labelled versions of AJ‐9677, a novel anti‐diabetic drug candidate, have been synthesized. The first, [acetic acid‐2‐14C]AJ‐9677, was synthesized via a four‐step process starting from 2‐chloro‐N,N‐diethyl[2‐14C]acetamide (3), and the second, [hydroxymethine‐14C]AJ‐9677, by a two step process from (R)‐3‐chloro[7‐14C]styrene oxide (8). When stored in the solid state both compounds undergo radiolytic decomposition in a similar manner, despite the labelled position being different, to give the dechlorinated derivative (12a, 12b). Purification of the required product was achieved after derivatization to the methyl esters. Copyright © 2004 John Wiley & Sons, Ltd.
Late‐glacial and Holocene river development in the Teleorman Valley on the southern Romanian Plain
Authors: Howard A. J. , Macklin M. G. , Bailey D. W. , Mills S. , Andreescu R.
Published: April 2004

This paper reports on a radiocarbon‐dated sequence of alluvial terraces from the Teleorman Valley in the southern Romanian Plain and represents the first Late‐glacial and well‐constrained Holocene alluvial sequence from the lower Danube Valley of southeast Europe. The two earliest and most extensive terraces (T1 and T2) are dissected by large, high‐amplitude palaeochannels, which are dated to ca. 12 800 yr BP and are comparable to large meandering palaeochannels identified from other Late glacial contexts across northern and central Europe. The remaining sequence of alluvial deposits show changes in river activity and accelerated sedimentation around 4900–4800 yr BP, 4000–3800 yr BP, 3300–2800 yr BP, 1000 yr BP and within the past 200 yr. A phase of tributary stream alluvial fan deposition is dated to ca. 2400 yr BP. All these periods of alluvial sedimentation correlate well with episodes of climatic cooling, higher rainfall and enhanced river activity, both in terms of incision and greater lateral mobility as well as increased flood frequency and magnitude identified elsewhere in central, western and northern Europe. Human activity appears to have had little effect on this river environment and significant fine‐grained sedimentation is not noted until ca. 2400 yr BP, approximately 5000 yr after the first neolithic farmers settled the area. Whether this record of river activity truly reflects the impact of prehistoric societies on this catchment will only be elucidated through further, ongoing detailed archaeological research. Copyright © 2003 John Wiley & Sons, Ltd.
The Preboreal climate reversal and a subsequent solar‐forced climate shift
Authors: van der Plicht J. , van Geel B. , Bohncke S. J. P. , Bos J. A. A. , Blaauw M. , Speranza A. O. M. , Muscheler R. , Björck S.
Published: April 2004

Accurate chronologies are essential for linking palaeoclimate archives. Carbon‐14 wiggle‐match dating was used to produce an accurate chronology for part of an early Holocene peat sequence from the Borchert (The Netherlands). Following the Younger Dryas–Preboreal transition, two climatic shifts could be inferred. Around 11 400 cal. yr BP the expansion of birch (Betula) forest was interrupted by a dry continental phase with dominantly open grassland vegetation, coeval with the PBO (Preboreal Oscillation), as observed in the GRIP ice core. At 11 250 cal. yr BP a sudden shift to a humid climate occurred. This second change appears to be contemporaneous with: (i) a sharp increase of atmospheric 14C; (ii) a temporary decline of atmospheric CO2; and (iii) an increase in the GRIP 10Be flux. The close correspondence with excursions of cosmogenic nuclides points to a decline in solar activity, which may have forced the changes in climate and vegetation at around 11 250 cal. yr BP. Copyright © 2004 John Wiley & Sons, Ltd.
The Younger Dryas and Holocene climate record of a stalagmite from Hölloch Cave (Bavarian Alps, Germany
Authors: Wurth Georg , Niggemann Stefan , Richter Detlev K. , Mangini Augusto
Published: April 2004

Stable isotope analyses and seven U/Th dates of a stalagmite from the alpine Hölloch Cave (Germany) have yielded a palaeoclimate record for the past 14 300 yr. The δ18O record is positively correlated with relative temperature variations. The late glacial part of this record, including the Younger Dryas, exhibits a striking correlation with records from ice cores, lake sediments and marine sediments. In addition, this record suggests relatively high temperatures and distinct temperature fluctuations from 9000–4200 yr BP, if compared with the 4200–0 yr BP period, matching the regional soil formation–erosion and timberline patterns. The δ13C record appears to have been controlled mainly by soil formation (14 300–9000 yr BP) and by humidity variations (9000–0 yr BP). Copyright © 2004 John Wiley & Sons, Ltd.
Raman spectroscopic detection of wyartite in the presence of rabejacite
Authors: Frost Ray L. , Henry Dermot A. , Erickson Kristy
Published: April 2004

Raman microscopy was used to confirm the presence of wyartite, CaU5+(UO2)2(CO3)O4(OH)(H2O)7, in the presence of rabejacite, (Ca(UO2)4(SO4)2(OH)5·6H2O), obtained from the Ranger Mine, Northern Territory, Australia. This occurrence is unusual in that it means that a uranyl carbonate has been formed under acidic conditions. Wyartite is a mineral known for the occurrence of pentavalent U5+. A band is observed at 818 cm−1 in the Raman spectrum of wyartite assigned to the ν2 symmetric bending mode of the (CO3)2− units. The presence of carbonate is confirmed by the ν1 stretching vibration at 1071 cm−1 and the ν3 stretching vibrations at 1445 and 1345 cm−1. Two bands are observed at 853 and 837 cm−1 and are assigned to the ν1 stretching modes of the UO2 units. Raman spectroscopy allows the partial band separation of the ν2 (CO3)2− and ν1 modes of UO2. The Raman spectrum of rabejacite is characterized by an intense sharp band at 1010 cm−1 assigned to the ν1 stretching mode of (SO4)2−. Three bands observed at 1086, 1123 and 1175 cm−1 are attributed to the ν3 antisymmetric stretching modes of (SO4)2−. The mineral rabejacite is also characterized by ν2 bending modes at 457 and 394 cm−1 and ν4 bending modes at 666, 605, 537 and 505 cm−1. Raman spectroscopy has proven most useful for the detection of wyartite in the presence of other mineral phases. Copyright © 2004 John Wiley & Sons, Ltd.
(Nano)structure, skin/core and tension behaviour of polyamide fibres
Authors: Marcellan Alba , Colomban Philippe , Bunsell Anthony
Published: April 2004

The micro/nanostructural evolution of ultrahigh‐performance and textile (containing a dispersion of TiO2 powder) polyamide 66 fibres during tensile loading and failure initiation was studied using Raman spectroscopy low‐wavenumber collective modes (∼100 cm−1) as a mechanical probe representative of the crystalline domains. The analysis of the wavenumber distribution revealed the skin/core heterogeneity. A compressive residual stress in the skin was evaluated at about 200 MPa from calibration plots. The homogeneity of the TiO2 grain dispersion was mapped on fibre sections and scanned along their lengths. In situ analysis at different strain levels shows that the amorphous region accommodates the stress up to ca 350 MPa, from which point elastic behaviour is observed. Particular attention was devoted to analysing crack formation. Copyright © 2004 John Wiley & Sons, Ltd.
Oxidation of lactic acid by water soluble (colloidal) manganese dioxide
Authors: Khan Zaheer , Raju  , Akram Mohd. , Kabir‐ud‐Din
Published: April 2004

Spectrophotometric method has been used to characterize water‐soluble colloidal manganese dioxide obtained by the redox reaction between sodium thiosulphate and potassium permanganate in neutral aqueous medium which shows a single peak in the visible region with λmax = 425 nm. The kinetics of the oxidation of lactic acid by colloidal manganese dioxide (oxidant) has been investigated spectrophotometrically under pseudo‐first‐order conditions of excess lactic acid. The rate of the noncatalytic reaction pathway was slow which increased with increasing lactic acid concentration. The reaction was first‐order with respect to [oxidant] as well as [lactic acid]. In presence of manganase(II) and fluoride ions, the noncatalytic path disappeared completely while the oxidation rate of autocatalytic path increased and decreased, respectively with increasing [Mn(II)] and [F−]. A mechanistic scheme in conformity with the observed kinetics has been proposed with the rate‐law:

equation image

© 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 359–366 2004
Fabrication of Temperature‐Sensitive Imprinted Polymer Hydrogel
Authors: Liu Xue‐Yong , Ding Xiao‐Bin , Guan Ying , Peng Yu‐Xing , Long Xin‐Ping , Wang Xiao‐Chuan , Chang Kun , Zhang Yong
Published: April 2004

Summary: Weakly cross‐linked temperature sensitive gels that memorize 4‐aminopyridine molecules were designed and synthesized. The polymer gels show special selectivity, good thermo‐sensitivity and reusability, which would have an enormous potential of application in drug controlled release systems.

Adsorption of Apy by the imprinted and non‐imprinted gels in the shrunken state at 60 °C.

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Adsorption of Apy by the imprinted and non‐imprinted gels in the shrunken state at 60 °C.
A note on Grzegorczyk's logic
Authors: Jeřábek Emil
Published: April 2004

Grzegorczyk's modal logic (Grz) corresponds to the class of upwards well‐founded partially ordered Kripke frames, however all known proofs of this fact utilize some form of the Axiom of Choice; G. Boolos asked in [1], whether it is provable in plain ZF. We answer his question negatively: Grz corresponds (in ZF) to a class of frames, which does not provably coincide with upwards well‐founded posets in ZF alone. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On deciding the non‐emptiness of 2SAT polytopes with respect to First Order Queries
Authors: Subramani K.
Published: April 2004

This paper is concerned with techniques for identifying simple and quantified lattice points in 2SAT polytopes. 2SAT polytopes generalize the polyhedra corresponding to Boolean 2SAT formulas, Vertex‐Packing (Covering, Partitioning) and Network flow problems; they find wide application in the domains of Program verification (Software Engineering) and State‐Space search (Artificial Intelligence). Our techniques are based on the symbolic elimination strategy called the Fourier‐Motzkin elimination procedure and thus have the advantages of being extremely simple (from an implementational perspective) and incremental. We also provide a characterization of a 2SAT polytope in terms of its extreme points and derive some interesting hardness results for associated optimization problems. Finally, we provide a brief discussion on the maximum size of a subdeterminant of the linear system representing a 2SAT polytope; this parameter plays a vital role in deriving analytical bounds on the size of the search space for checking whether the polyhedron includes a lattice point. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On weakening the Deduction Theorem and strengthening Modus Ponens
Authors: Bou Félix , Font Josep Maria , García Lapresta José Luis
Published: April 2004

This paper studies, with techniques of Abstract Algebraic Logic, the effects of putting a bound on the cardinality of the set of side formulas in the Deduction Theorem, viewed as a Gentzen‐style rule, and of adding additional assumptions inside the formulas present in Modus Ponens, viewed as a Hilbert‐style rule. As a result, a denumerable collection of new Gentzen systems and two new sentential logics have been isolated. These logics are weaker than the positive implicative logic. We have determined their algebraic models and the relationships between them, and have classified them according to several standard criteria of Abstract Algebraic Logic. One of the logics is protoalgebraic but neither equivalential nor weakly algebraizable, a rare situation where very few natural examples were hitherto known. In passing we have found new, alternative presentations of positive implicative logic, both in Hilbert style and in Gentzen style, and have characterized it in terms of the restricted Deduction Theorem: it is the weakest logic satisfying Modus Ponens and the Deduction Theorem restricted to at most 2 side formulas. The algebraic part of the work has lead to the class of quasi‐Hilbert algebras, a quasi‐variety of implicative algebras introduced by Pla and Verdú in 1980, which is larger than the variety of Hilbert algebras. Its algebraic properties reflect those of the corresponding logics and Gentzen systems. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
EM + Ext− + ACint is equivalent to ACext
Authors: Carlström Jesper
Published: April 2004

It is well known that the extensional axiom of choice (ACext) implies the law of excluded middle (EM). We here prove that the converse holds as well if we have the intensional (‘type‐theoretical’) axiom of choice ACint, which is provable in Martin‐Löf's type theory, and a weak extensionality principle (Ext−), which is provable in Martin‐Löf's extensional type theory. In particular, EM is equivalent to ACext in extensional type theory. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and Characterization of Polystyrene‐Encapsulated Laponite Composites via Miniemulsion Polymerization
Authors: Sun Qunhui , Deng Yulin , Wang Zhong Lin
Published: April 2004

Summary: A novel polystyrene‐encapsulated laponite composite system has been developed via a miniemulsion polymerization approach. The encapsulation mechanism and process parameters have been examined in detail using light‐scattering, sedimentation analysis, wide‐angle X‐ray diffraction (WXRD), and transmission electron microscopy (TEM). The laponite was encapsulated through a miniemulsion polymerization process in which laponite was predispersed in the monomer phase. The stability of both the miniemulsion and the latex depends on initiation loci, premixing procedures, intensity and time of ultrasonification and the surfactants and co‐stabilizer used. Hydrophobicity of the laponite clay played a vital role in both the encapsulation of the clay and the stability of the latex. A quaternary ammonium salt, cetyltrimethylammonium bromide (CTAB), was mixed with the clay in the monomer phase prior to emulsification. As a result, the clay particles were hydrophobically modified and were intercalated. The hydrophobicity not only favored the clay dispersion in the oil droplets but also aided the entry of the monomer into the clay's intergalleries during polymerization. Meanwhile, CTAB helped stabilize the system when it was used in conjunction with the nonionic surfactant polyoxyethylene (40) isooctylphenyl ether (TX‐405). In this way, the laponite is effectively encapsulated within a polystyrene shell in a stable latex form. More importantly, the polymerization initiated in the intergalleries of the clay effectively expands the clay's platelet array to form an exfoliated structure.

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Solid‐State Structure and Mechanical Properties of Blends of an Amorphous Polyamide and a Poly(amino‐ether) Resin
Authors: Granado Ainhoa , Eguiazábal José I. , Nazábal Jon
Published: April 2004

Summary: Finely dispersed blends of an amorphous polyamide (AP) and a poly(amino‐ether) (PAE) resin were obtained by direct injection moulding. The blend components reacted slightly, mainly in PAE‐rich compositions, as seen by torque increases and FT‐IR. Both negative volumes of mixing and preferential orientation were observed in blends with very high AP contents, leading to synergisms in both the modulus of elasticity and the yield stress. In PAE‐rich blends, the effects of these two structural characteristics were negative, but the higher presence of reacted products also led to an overall synergistic modulus of elasticity. With the exception of blends very rich in PAE, in which the more extensive reactions led to brittle materials, the reactions compatibilized the blends due to the presence of small amounts of reacted copolymers, probably at the interface.

Cryogenically fractured surface of the skin of the AP/PAE 80/20 w/w blend.

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Cryogenically fractured surface of the skin of the AP/PAE 80/20 w/w blend.
Dextran Hydrogels Containing Poly(N‐isopropylacrylamide) as Grafts and Cross‐Linkers Exhibiting Enzymatic Regulation in a Specific Temperature Range
Authors: Kumashiro Yoshikazu , Ooya Tooru , Yui Nobuhiko
Published: April 2004

Summary: Specific temperature‐responsive biodegradable hydrogels were synthesized and characterized in terms of their regulation of enzymatic accessibility based on the physical properties of the temperature‐responsive polymers. The hydrogels consist of glycidyl methacrylate‐modified dextran grafted with the poly(N‐isopropylacrylamide) (PNIPAAm) homopolymer, and cross‐linked by co‐polymerization with NIPAAm and N,N‐dimethylacrylamide (DMAAm). The coil‐globule change in the grafted poly(NIPAAm) chains and only a slight dehydration of the poly(NIPAAm‐co‐DMAAm) cross‐linkers are effective in controlling the enzymatic degradation over a specific temperature range.

The thermo‐responses of the graft chains (steric hindrance) and the crosslinkers (slight deswelling of the hydrogel networks) control the enzymatic degradation of the hydrogel.

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The thermo‐responses of the graft chains (steric hindrance) and the crosslinkers (slight deswelling of the hydrogel networks) control the enzymatic degradation of the hydrogel.
Cationic Polymerization of 3‐Ethyl‐3‐hydroxymethyloxetane in an Ionic Liquid
Authors: Biedroń Tadeusz , Bednarek Melania , Kubisa Przemysław
Published: April 2004

Summary: Cationic ring‐opening polymerization of 3‐ethyl‐3‐hydroxymethyloxetane (EOX) in a neutral ionic liquid (1‐butyl‐3‐methylimidazolium tetrafluoroborate, [bmim][BF4]) leading to a multihydroxyl, branched polyether proceeds readily to nearly quantitative conversion. Because of the relatively high polarity of ionic liquids, intermolecular hydrogen bonding leading to the formation of aggregates is reduced considerably. On the other hand, intramolecular hydrogen bonding facilitating intramolecular chain transfer is not significantly affected and the molecular weights of polymers are in the same range as those obtained in bulk polymerization or polymerization in organic solvents.

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Mass spectrometric approaches for the investigation of dynamic processes in condensed phase
Authors: Fabris Daniele
Published: April 2004

I.
Introduction
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 II.
Off‐Line Sampling
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A.  Quantitative Approaches for Kinetics Determinations
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B.  Characterization of Intermediates in Chemical Reactions
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C.  Off‐Line Investigation of Catalysis in Biological Systems
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III.
Continuous On‐Line Monitoring
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IV.
Rapid Mixing
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 V.
Conclusions
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VI.
Abbreviations and Acronyms
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Acknowledgments
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References
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Mass spectrometry (MS) offers many advantages over other established spectroscopic techniques employed for the investigation of processes in condensed phase. The sensitivity, specificity, and speed afforded by MS‐based methods enable to obtain very valuable insights into the mechanism of complex dynamic processes. Off‐line methods rely on quenching to halt the progress of the reaction of interest and allow for the implementation of a broad range of analytical procedures for sample fractionation, isolation, or desalting. On the contrary, on‐line methods are designed to carry out the real‐time monitoring of dynamic processes through a continuous uninterrupted analysis of reaction mixtures, with the only caveat that the sample solutions be directly amenable to the available ionization technique. The utilization of rapid mixing devices in direct connection with a mass spectrometer or included in off‐line schemes provides access to the initial moments of a reaction, which can offer very important information about the reaction mechanism. This report summarizes the different off‐ and on‐line strategies developed to study chemical and biochemical reactions in solution and obtain kinetic/mechanistic information. The merits of the various experimental designs, the characteristics of the different instrumental setups, and the factors affecting time resolution are discussed with the aid of specific examples, which highlight the contributions of MS to the different facets of the investigation of dynamic processes in condensed phase. © 2004 Wiley Periodicals, Inc.
Absence of sensory neuropathy among workers with occupational exposure to chlorpyrifos
Authors: Albers James W. , Garabrant David H. , Schweitzer Sarah , Garrison Richard P. , Richardson Rudy J. , Berent Stanley
Published: April 2004

Several studies have reported the occurrence of sensory neuropathy with exposure to chlorpyrifos and other organophosphorus insecticides, at levels not associated with overt toxicity. We evaluated 113 chemical workers, including 53 of 66 (80%) eligible chlorpyrifos workers and 60 of 74 (81%) randomly selected referent workers, to identify evidence of sensory neuropathy or subclinical neuropathy. Compared to referents, chlorpyrifos subjects had significantly longer duration of work in chlorpyrifos‐exposed areas (9.72 vs. 0.01 years; P < 0.0001), greater cumulative chlorpyrifos exposure (64.16 vs. 0.69 mg/m3 · day; P < 0.0001), higher urine 3,5,6‐trichloro‐2‐pyridinol (TCP) excretion (108.6 vs. 4.3 μg/g creatinine; P < 0.0001), and lower plasma butyrylcholinesterase (BuChE) activity (7281 vs. 8176 mU/ml; P = 0.003). Despite exposures among chlorpyrifos subjects to levels at which well‐described physiological effects on B‐esterases exist, the frequency of symptoms or signs of neuropathy did not differ significantly between groups, and the only 2 subjects fulfilling criteria for confirmed neuropathy were both in the referent group. Mean nerve conduction study results were comparable to established control values and did not differ significantly between groups. We found no evidence of sensory neuropathy or isolated peripheral abnormalities among subjects with long‐term chlorpyrifos exposure at levels known to be associated with the manufacturing process. Muscle Nerve 29: 677–686, 2004
Nerve excitability properties in lower‐limb motor axons: Evidence for a length‐dependent gradient
Authors: Krishnan Arun V. , Lin Cindy S.‐Y. , Kiernan Matthew C.
Published: April 2004

In this study, nerve excitability protocols were adapted for lower‐limb recordings in 25 healthy subjects to enable comparison of excitability parameters between proximal and distal recording sites of the same nerve and between different nerves. Excitability parameters (stimulus–response curves, strength–duration properties, threshold electrotonus, a current–threshold relationship, and the recovery cycle) were recorded from tibialis anterior, extensor digitorum brevis, and abductor hallucis. Excitability recordings were technically possible from each site, and normative values were established for lower‐limb nerves. In this process, inter‐ and intranerve differences in excitability properties were demonstrated: stimulus intensity and rheobase were reduced in recordings from proximal sites; the relative refractory period and late subexcitability were increased; superexcitability was reduced; and a relative “fanning‐in” occurred for threshold electrotonus curves recorded from proximal sites. Such a length‐dependent gradient in nerve excitability may underlie the greater tendency for ectopic activity to arise from the proximal segments of motor axons and may contribute to the length‐dependent involvement of motor axons in the development of peripheral neuropathy. Muscle Nerve 29: 645–655, 2004
Effect of creatine supplementation on skeletal muscle of mdx mice
Authors: Louis Magali , Raymackers Jean Marc , Debaix Huguette , Lebacq Jean , Francaux Marc
Published: April 2004

Dystrophic mice (mdx) and their controls (C57/Bl10) were fed for 1 month with a diet with or without creatine (Cr) enrichment. Cr supplementation reduced mass (by 19%, P < 0.01) and mean fiber surface (by 25%, P < 0.05) of fast‐twitch mdx muscles. In both strains, tetanic tension increased slightly (9.2%) without reaching statistical significance (P = 0.08), and relaxation time increased by 16% (P < 0.001). However, Cr had no protective effect on the other hallmarks of dystrophy such as susceptibility to eccentric contractions; large numbers of centrally nucleated fibers in tibialis anterior; and elevated total calcium content, which increased by 85% (P = 0.008) in gastrocnemius mdx muscles. In conclusion, Cr may be a positive intervention for improving function of dystrophic muscle. Muscle Nerve 29: 687–692, 2004
The challenge of public sector reform in EC accession countries: reflections from the Baltics, especially Latvia
Authors: Jacobs Colin
Published: April 2004

This article considers some of the key issues in reforming the public sector in Central and Eastern Europe (CEE). Drawing on the experience of donor funded projects, some conclusions are drawn about the process of public sector reform with particular reference to Latvia. In particular, it is argued that the process will take time but strategic choices need to be made in the absence of obvious demands from within the country. Several constraints are noted which together constitute formidable barriers to progress. However, the results of work to date provide some optimism for pilot approaches to strategic budgeting in reformist ministries. A simple checklist is used as a yardstick for progress in the main areas of public administration reform. Copyright © 2004 John Wiley & Sons, Ltd.
Gastrointestinal stromal tumours (GISTs) negative for KIT (CD117 antigen) immunoreactivity
Authors: Debiec‐Rychter Maria , Wasag Bartosz , Stul Michel , De Wever Ivo , Van Oosterom Allan , Hagemeijer Anne , Sciot Raf
Published: April 2004

Gastrointestinal stromal tumours (GISTs) are currently defined as mesenchymal tumours of the gastrointestinal tract that express KIT receptor tyrosine kinase. However, a small subgroup of tumours that fulfil the clinical and morphological criteria for GISTs lack KIT expression. So far, the biological features of these tumours have rarely been addressed. The present study describes seven gastrointestinal stromal neoplasms that presented clinicopathological features typical of GISTs but showed absence of CD117 expression as detected by immunohistochemistry. The tumours originated from the stomach (n = 5), duodenum (n = 1), and colon (n = 1), showing histologically either predominantly epithelioid (n = 3), mixed spindled and epithelioid (n = 2), or anaplastic/spindle cell (n = 2) type features. CD34 and α‐smooth muscle actin (α‐SMA) positivity was present in four and three tumours, respectively. Chromosomal analysis was performed in two cases, both showing losses of chromosomes 14, 22, and 1p, which is the characteristic feature of GISTs. Dual‐colour interphase fluorescence in situ hybridization (FISH) analysis, utilizing chromosome 1p‐, 14‐, and 22‐specific probes, revealed a similar cytogenetic profile in the remaining five tumour specimens. Mutational analysis of exons 9, 11, 13, and 17 of KIT, and exons 12 and 18 of PDGFRA was performed in all cases by denaturing high‐pressure liquid chromatography (DHPLC) pre‐screening, followed by direct sequencing. None of the tumours showed KIT mutant isoforms. Three tumours harboured PDGFRA exon 18 activating mutations; two were Asp → Val842 missense substitutions and one was a DIM842–844 amino acid deletion. KIT and PKCθ (protein activated in interstitial cells of Cajal and GISTs) expression was determined by western immunoblotting of the total cell lysates from three tumour biopsies. None of these three tumours expressed KIT, while all specimens showed expression of PKCθ protein. These findings indicate that there is a subgroup of KIT‐negative GISTs that exhibit the same morphological, cytogenetic, and molecular features as KIT‐positive tumours. While intragenic PDGFRA activating mutations are present in some of these tumours, the oncogenic events underlying the pathogenesis of the others remain unknown. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Modification of recycled high‐density polyethylene by low‐density and linear‐low‐density polyethylenes
Authors: Kukaleva N. , Simon G. P. , Kosior E.
Published: April 2004

The present study investigated mixed polyolefin compositions with the major component being a post‐consumer, milk bottle grade high‐density polyethylene (HDPE) for use in large‐scale injection moldings. Both rheological and mechanical properties of the developed blends are benchmarked against those shown by a currently used HDPE injection molding grade, in order to find a potential composition for its replacement. Possibility of such replacement via modification of recycled high‐density polyethylene (reHDPE) by low‐density polyethylene (LDPE) and linear‐low‐density polyethylene (LLDPE) is discussed. Overall, mechanical and rheological data showed that LDPE is a better modifier for reHDPE than LLDPE. Mechanical properties of reHDPE/LLDPE blends were lower than additive, thus demonstrating the lack of compatibility between the blend components in the solid state. Mechanical properties of reHDPE/LDPE blends were either equal to or higher than calculated from linear additivity. Capillary rheological measurements showed that values of apparent viscosity for LLDPE blends were very similar to those of the more viscous parent in the blend, whereas apparent viscosities of reHDPE/LDPE blends depended neither on concentration nor on type (viscosity) of LDPE. Further rheological and thermal studies on reHDPE/LDPE blends indicated that the blend constituents were partially miscible in the melt and cocrystallized in the solid state.