bluuebunny/crossref_metadata_2025 huggingface dataset:
Viable theoretical forms of synchronous production innovation
Authors: Georgantzas Nicholas C. , Shapiro H.Jack
Published: October 2002

Knowing what theoretical forms might best describe the relationships among administrative innovation, technological innovation and organizational performance can help production managers improve performance. Managers may adopt either administrative or technological innovation depending on how they perceive the form of these relationships. Alternatively, managers can plan for and implement synchronous innovation aiming at its synergistic effects on organizational performance.

Defined as the coincident‐in‐time adoption of compatible technological and administrative innovations, “synchronous” innovation is emerging as a response to the increased rivalry from offshore competitors. Prevailing theoretical forms of synchronous innovation emerge from the administrative and technological research perspectives of organizational innovation. Yet, it is the perceived form of synchronous innovation which determines where in its causal network of relationships production managers intervene to improve performance.

Assuredly, performance improvements may require a detailed inquiry into a firm's specific situation. Depending on the situation, the relationships among administrative innovation, technological innovation and organizational performance can yield alternative or complementary forms of synchronous innovation. Production managers and researchers encounter such forms in various organizational settings. Exploring several perceived forms of synchronous innovation is therefore pertinent to production research and practice.

To examine production managers' perceptions of synchronous innovation, this paper combines the administrative and technological perspectives of organizational innovation into four descriptive models of synchronous innovation. Drawing upon a diverse sample from the organizational innovation literature, each model incorporates both administrative and technological innovation dimensions, organizational performance dimensions and the causal interconnections among these three constructs. Thirty‐five plant managers' perceptions of the relationships underlying synchronous innovation provide data suitable for testing the viability of the four models.

The data show how administrative and technological innovation dimensions interact with, intervene among or moderate the contributions of each other on organizational performance, rendering their independent effects negligible without synchronous innovation. Firms may improve performance significantly by emphasizing either administrative or technological innovation alone. Yet, our results support the necessity of adopting a fine‐grained approach to organizational innovation research and practice. Understanding the effects of innovation on organizational performance requires scrutinizing the effects of administrative innovation when predicting the effects of technological innovation, and vice versa.
Characterization of an Arabidopsis thaliana mutant with impaired psbO, one of two genes encoding extrinsic 33‐kDa proteins in photosystem II
Authors: Murakami Reiko , Ifuku Kentaro , Takabayashi Atsushi , Shikanai Toshiharu , Endo Tsuyoshi , Sato Fumihiko
Published: October 2002

A 33‐kDa protein component of the oxygen‐evolving complex in photosystem II is essential for photosynthesis, and it has been believed that mutants with deletion of this 33‐kDa protein are not found in higher plants. We report here the first isolation of an Arabidopsis thaliana mutant with a defect in one of the genes for the 33‐kDa proteins, psbO, and an intact gene (psbO2). This mutant showed considerable growth retardation, suggesting that there is a functional difference between psbO and psbO2.
The tolbutamide site of SUR1 and a mechanism for its functional coupling to KATP channel closure
Authors: Babenko Andrey P , Gonzalez Gabriela , Bryan Joseph
Published: October 2002

Micromolar concentrations of tolbutamide will inhibit (SUR1/KIR6.2)4 channels in pancreatic β‐cells, but not (SUR2A/KIR6.2)4 channels in cardiomyocytes. Inhibition does not require Mg2+ or nucleotides and is enhanced by intracellular nucleotides. Using chimeras between SUR1 and SUR2A, we show that transmembrane domains 12–17 (TMD12‐17) are required for high‐affinity tolbutamide inhibition of KATP channels. Deletions demonstrate involvement of the cytoplasmic N‐terminus of KIR6.2 in coupling sulfonylurea‐binding with SUR1 to the stabilization of an interburst closed configuration of the channel. The increased efficacy of tolbutamide by nucleotides results from an impairment of their stimulatory action on SUR1 which unmasks their inhibitory effects. The mechanism of inhibition of β‐cell KATP channels by sulfonylureas during treatment of non‐insulin‐dependent diabetes mellitus thus involves two components, drug‐binding and conformational changes within SUR1 which are coupled to the pore subunit through its N‐terminus and the disruption of nucleotide‐dependent stimulatory effects of the regulatory subunit on the pore. These findings uncover a molecular basis for an inhibitory influence of SUR1, an ATP‐binding cassette (ABC) protein, on KIR6.2, a ion channel subunit.
Direct evidence of cytoplasmic delivery of PKC‐α, ‐ϵ and ‐ζ pseudosubstrate lipopeptides: study of their implication in the induction of apoptosis
Authors: Thiam Kader , Loing Estelle , Zoukhri Driss , Rommens Corinne , Hodges Robin , Dartt Darlene , Verwaerde Claudie , Auriault Claude , Gras-Masse Hélène , Sergheraert Christian
Published: October 2002

Protein kinases C (PKC) are serine/threonine kinase enzymes involved in the mechanism of cell survival. Their pseudosubstrate sequences are autoinhibitory domains, which maintain the enzyme in an inactive state in the absence of allosteric activators, thus representing an attractive tool for the modulation of different PKC isoforms. Here, we report the use of palmitoylated modified PKC‐α, ‐ϵ, and ‐ζ pseudosubstrate peptides, and determine their intracellular distribution together with their respective PKC isoenzymes. Finally, we propose that the differential distribution of the peptides is correlated with a selective induction of apoptosis and therefore argues for different involvement of PKC isoforms in the anti‐apoptotic program.
Mixing enhancement via the release of
strongly nonlinear longitudinal Görtler
vortices and their secondary instabilities
into the mixing region
Authors: GIRGIS I. G. , LIU J. T. C.
Published: October 2002

Mixing enhancement in a mixing layer is considered in terms of a ‘vortex generator’
that uses fluid dynamically generated counter-rotating longitudinal vortices rather
than explicit winglets or similar devices. This view is reached through considering
the centrifugal instability of weak initial Görtler vortices on a slightly concave wall
that are allowed to develop to their various nonlinear stages through selecting the
cutoff lengths of the trailing edge prior to their release into the mixing region. These
vortices are released from one side of the (say, upper) stream in the present work. The
quantitative entrainment properties of the longitudinal vortices are studied to select
an optimal trailing-edge cutoff for fixed upstream conditions. As the vortices develop
along the wall, they are intensified because of the centrifugal instability mechanism
and because of the work done by the Reynolds stress of the vortices against the local
mean flow rate of strain; simultaneously, the region of strong streamwise vorticity
moves away from the wall. This selection process is explained through a balance
between the vorticity strength and proximity to the lower stream when the trailing
edge is cut off: it is shown, therefore, that vortices of relatively modest strength and
kinetic energy that are close to the interface separating the two streams provide mixing
properties superior to stronger vortices located too far from the interface.
Energy-balancing mechanisms and the stretching of the initial interface are studied, as are the
effects of the velocity ratio and the spanwise wavelengths other than the fundamental.
In order further to enhance mixing by exploiting the inherent secondary instability of
primary steady longitudinal vortices, the most amplified secondary instability of the
optimal-trailing-edge cutoff situation, which is the sinuous mode, is studied in detail
in terms of the nonlinear development and modification of the steady vortical flow.
Local energy-exchange mechanisms are studied, as are the mixing properties of the
modified steady flow, which are shown to be significantly improved compared to the
unmodified steady flow. Though the initiation of steady longitudinal vortices relies
on centrifugal instability upstream, such vortices are able to develop self-sustaining
and amplifying properties through the Reynolds stresses in the mixing region even
without centrifugal instability reinforcement. The secondary instability is initiated
and sustained entirely through its own three-dimensional Reynolds stress properties,
which work against the three-dimensional rates of strain in the entire steady flow.
This contrasts with initially generated potential-like vortices that decay downstream
in the presence of dissipative mechanisms without the production mechanisms due to
the Reynolds stresses.
Exact second-order structure-function
relationships
Authors: HILL REGINALD J.
Published: October 2002

Equations that follow from the Navier–Stokes equation and incompressibility but
with no other approximations are ‘exact’. Exact equations relating second- and third-
order structure functions are studied, as is an exact incompressibility condition on
the second-order velocity structure function. Opportunities for investigations using
these equations are discussed. Precisely defined averaging operations are required
to obtain exact averaged equations. Ensemble, temporal and spatial averages are
all considered because they produce different statistical equations and because they
apply to theoretical purposes, experiment and numerical simulation of turbulence.
Particularly simple exact equations are obtained for the following cases: (i) the trace
of the structure functions, (ii) DNS that has periodic boundary conditions, and
(iii) an average over a sphere in r-space. Case (iii) introduces the average over
orientations of r into the structure-function equations. The energy dissipation rate ε
appears in the exact trace equation without averaging, whereas in previous formulations ε appears after averaging and use of local isotropy. The trace mitigates the
effect of anisotropy in the equations, thereby revealing that the trace of the third-order
structure function is expected to be superior for quantifying asymptotic scaling laws.
The orientation average has the same property.
First record of the bivalve-inhabiting hydroid Eugymnanthea inquilina in the eastern Mediterranean Sea (Gulf of Thessaloniki, north Aegean Sea, Greece)
Authors: Rayyan Abdalnasser , Christidis John , Chintiroglou Chariton C.
Published: October 2002

The first record of a bivalve-inhabiting hydrozoan Eugymnanthea inquilina was found in Thermaikos Gulf, north Aegean Sea, eastern Mediterranean Sea, associated with Mytilus galloprovincialis. Analyses of biometric data point the same biological differences between the Mediterranean and the Japanese Eugymnanthea, as reported by previous researchers.
First confirmed record of the Chinese mitten crab (Eriocheir sinensis) from the River Tyne, United Kingdom
Authors: Herborg L.-M. , Bentley M.G. , Clare A.S.
Published: October 2002

Two specimens of the Chinese mitten crab Eriocheir sinensis (Crustacea: Decapoda: Brachyura) were caught in the River Tyne, north-east England during 2001. The specimens were brought back to the laboratory, sexed, measured and stored in 95% ethanol. Unconfirmed reports of this species' occurrence in the River Tyne were first circulated in 1997.
The troubles with ‘celebrity’: community formation in senior public housing
Authors: FAIRCLOTH CHRISTOPHER A.
Published: October 2002

In the study of ageing, community has increasingly become a topic of interest. Ageing studies are certainly not alone in this, for the same is widely true in the contemporary American social sciences. More and more research, often quite theoretical, suggests that we must raise the sense of community to achieve improvements in the quality of life. In gerontology, over the past decade studies of nursing homes and housing settings have burgeoned. For the most part, however, analyses have focused on the need for community through social integration, while the underlying question, of how community is formed through social interaction, has been neglected. Community, as discussed here, grows out of interaction in a local setting. The interaction is based on a shared or common knowledge of the site's occupants. In essence, community is not so much a site or location per se, but rather the activity of converting a site into a shared collectivity. In this article, the specific mechanisms through which community is formed in a senior, government-supported housing complex are documented. Using data from fieldwork in the neighbourhood, it is argued that, at this site, community is formed through talk about the neighbourhood's commonly recognised troubles. An important component of this ‘troubles talk’ is the celebrity status of two residents. Talk about them is an important component of the elaboration and elucidation of the commonalities that bind the residents together.
Support in old age in the changing society of Bangladesh
Authors: KABIR ZARINA NAHAR , SZEBEHELY MARTA , TISHELMAN CAROL
Published: October 2002

The assumption that social and economic transitions in a country pose a threat to the provision of support to older people is questioned in this study. The study investigates the availability and sources of such material, practical and emotional support in urban and rural areas of Bangladesh. The support provided by older people towards household functioning is also explored. It was found from an interview survey of 701 individuals aged 60 years and older that the propensity to receive support was greater among rural older people than their urban counterparts. Gender differences were also observed, in that men were mainly providers of material support, and women of practical and emotional support. Among married older people, spouses were reported as important sources of emotional support for both elderly men and women, and some regional differences were observed. The data show mutuality in the provision of support between older people and their family members. It is evident that support to elderly people from their families is strong in Bangladesh, and that the socio-cultural dynamics of the society influence its provision.
The illnesses of King Alfred the Great
Authors: Pratt David
Published: October 2002

It is an index perhaps of changing historiographical trends that the importance
of Alfred's illnesses in the moulding of his outlook, both as a layman and as a
king, now hardly needs to be emphasized. In the course of the 1990s, Alfred
became gradually better understood as a man of the 890s. Yet Victorian sensibilities
have died hard. Both Plummer and Stevenson detected an ‘atmosphere
of morbid religiosity’ in Asser's account of Alfred's illnesses in ch. 74,
and both refused to associate this atmosphere with the ‘historical Alfred’, in
view of his well-attested military successes. The recent resurrection of this
approach by Alfred Smyth has only served, however, to emphasize the need for greater sensitivity to the ideals and expectations of the society within which
Alfred was operating. Smyth's unsuccessful attempt to expose Asser's Life as a
later forgery relies heavily upon his assumption that the text is a work of hagiography,
because it supposedly portrays Alfred as ‘a saintly king, wrapt up in
prayer [sic], and enduring some form of physical disease’. It should therefore
be stressed that royal sanctity was an entirely posthumous phenomenon in
Anglo-Saxon England, and, in the case of kings, nearly always acquired through
an appropriate manner of death.
Junius's knowledge of the Old English
poem Durham
Authors: O'Donnell Daniel Paul
Published: October 2002

Until recently, the late Old English poem Durham was known to have been
copied in two manuscripts of the twelfth century: Cambridge, University
Library, Ff. 1. 27 (C) and London, British Library, Cotton Vitellius D. xx (V). C
has been transcribed frequently and serves as the basis for Elliott Van Kirk
Dobbie's standard edition of the poem in the Anglo-Saxon Poetic Records. V
was almost completely destroyed in the Cottonian fire of 1731. Its version is
known to us solely from George Hickes's 1705 edition (H).

In a recent article, however, Donald K. Fry announced the discovery of a third
medieval text of the poem. Like V, the original manuscript of this ‘third’ version
is now lost and can be reconstructed only from an early modern transcription - in
this case a copy by Francis Junius no win the Stanford University Library (Stanford
University Libraries, Department of Special Collections, Misc. 010 [J1]). Unlike V,
however, Junius's copy is our only record of this manuscript's existence. No other
transcripts are known from medieval or early modern manuscript catalogues.
Constructing Large Set Systems
with Given Intersection Sizes
Modulo Composite Numbers
Authors: KUTIN SAMUEL
Published: October 2002

We consider k-uniform set systems over a universe of size n such that the size of each
pairwise intersection of sets lies in one of s residue classes mod q, but k does not lie in any
of these s classes. A celebrated theorem of Frankl and Wilson [8] states that any such set
system has size at most (ns)
when q is prime. In a remarkable recent paper, Grolmusz [9]
constructed set systems of
superpolynomial size Ω(exp(c log2n/log log n)) when q = 6. We
give a new, simpler construction achieving a slightly improved bound. Our construction
combines a technique of Frankl [6] of ‘applying polynomials to set systems’ with Grolmusz's
idea of employing polynomials introduced by Barrington, Beigel and Rudich [5]. We also
extend Frankl's original argument to arbitrary prime-power moduli: for any ε > 0, we
construct systems of size ns+g(s), where g(s) = Ω(s1−ε).
Our work overlaps with a very
recent technical report by Grolmusz [10].
Mental space embeddings, counterfactuality, and the use of unless
Authors: Dancygier Barbara
Published: October 2002

Unless-constructions have often been compared with conditionals. It was noted that unless can in most cases be paraphrased with if not, but that its meaning resembles that of except if (Geis, 1973; von Fintel, 1991). Initially, it was also assumed that, unlike if-conditionals, unless-sentences with counterfactual (or irrealis) meanings are not acceptable. In recent studies by Declerck and Reed (2000, 2001), however, the acceptability of such sentences was demonstrated and a new analysis was proposed.

The present article argues for an account of irrealis unless-sentences in terms of epistemic distance and mental space embeddings. First, the use of verb forms in irrealis sentences is described as an instance of the use of distanced forms, which are widely used in English to mark hypotheticality. In the second part, the theory of mental spaces is introduced and applied to show how different mental space set-ups (in conjunction with distanced forms) account for the construction of different hypothetical meanings. The so-called irrealis unless-sentences are then interpreted as a number of instances of mental space embeddings. Finally, it is shown how the account proposed explains the fact that some unless-constructions can be paraphrased only with if not while others only with except if.
Coupling Sap Flow Velocity and Amino Acid Concentrations as an Alternative Method to 15N Labeling for Quantifying Nitrogen Remobilization by Walnut Trees
Authors: Frak Ela , Millard Peter , Le Roux Xavier , Guillaumie Sabine , Wendler Renate
Published: October 2002

The temporal dynamics of N remobilization was studied in walnut (Juglans nigra × regia) trees growing in sand culture. Trees were fed with labeled N (15N) during 1999 and unlabeled N in 2000. Total N and15N contents in different tree compartments were measured during 80 d after bud burst and were used to estimate N remobilization for spring growth. The seasonal (and occasionally diurnal) dynamics of the concentration and 15N enrichment of the major amino acids in xylem sap were determined concurrently. Sap flow velocity was also measured for sample trees. A new approach coupling amino acid concentrations to sap flow velocity for quantifying N remobilization was tested. A decrease of the labeled N contents of medium roots, tap roots, and trunk was observed concurrently to the increase in the labeled N content of new shoots. Remobilized N represented from previous year storage 54% of N recovered in new shoots. Arginine, citruline, γ-amino butyric acid, glutamic acid, and aspartic acid always represented around 80% of total amino acid and amide N in xylem sap and exhibited specific seasonal trends and significant diurnal trends. N translocation was mainly insured by arginine during the first 15 d after bud burst, and then by glutamic acid and citruline. The pattern of N remobilization estimated by the new approach was consistent with that measured by the classical labeling technique. Implications for quantifying N remobilization for large, field-growing trees are discussed.
Endoplasmic Microtubules Configure the Subapical Cytoplasm and Are Required for Fast Growth of Medicago truncatulaRoot Hairs
Authors: Sieberer Björn J. , Timmers Antonius C.J. , Lhuissier Franck G.P. , Emons Anne Mie C.
Published: October 2002

To investigate the configuration and function of microtubules (MTs) in tip-growing Medicago truncatularoot hairs, we used immunocytochemistry or in vivo decoration by a GFP linked to a MT-binding domain. The two approaches gave similar results and allowed the study of MTs during hair development. Cortical MTs (CMTs) are present in all developmental stages. During the transition from bulge to a tip-growing root hair, endoplasmic MTs (EMTs) appear at the tip of the young hair and remain there until growth arrest. EMTs are a specific feature of tip-growing hairs, forming a three-dimensional array throughout the subapical cytoplasmic dense region. During growth arrest, EMTs, together with the subapical cytoplasmic dense region, progressively disappear, whereas CMTs extend further toward the tip. In full-grown root hairs, CMTs, the only remaining population of MTs, converge at the tip and their density decreases over time. Upon treatment of growing hairs with 1 μm oryzalin, EMTs disappear, but CMTs remain present. The subapical cytoplasmic dense region becomes very short, the distance nucleus tip increases, growth slows down, and the nucleus still follows the advancing tip, though at a much larger distance. Taxol has no effect on the cytoarchitecture of growing hairs; the subapical cytoplasmic dense region remains intact, the nucleus keeps its distance from the tip, but growth rate drops to the same extent as in hairs treated with 1 μm oryzalin. The role of EMTs in growing root hairs is discussed.
Splicing of the Maize Sh1 First Intron Is Essential for Enhancement of Gene Expression, and a T-Rich Motif Increases Expression without Affecting Splicing
Authors: Clancy Maureen , Hannah L. Curtis
Published: October 2002

Certain plant and animal introns increase expression of protein-coding sequences when placed in the 5′ region of the transcription unit. The mechanisms of intron-mediated enhancement have not been defined, but are generally accepted to be post- or cotranscriptional in character. One of the most effective plant introns in stimulating gene expression is the 1,028-bp first intron of the Sh1 gene that encodes maize (Zea mays) sucrose synthase. To address the mechanisms of intron-mediated enhancement, we used reporter gene fusions to identify features of the Sh1 first intron required for enhancement in cultured maize cells. A 145-bp derivative conferred approximately the same 20- to 50-fold stimulation typical for the full-length intron in this transient expression system. A 35-bp motif contained within the intron is required for maximum levels of enhancement but not for efficient transcript splicing. The important feature of this redundant 35-bp motif is T-richness rather than the specific sequence. When transcript splicing was abolished by mutations at the intron borders, enhancement was reduced to about 2-fold. The requirement of splicing for enhancement was not because of upstream translation initiation codons contained in unspliced transcripts. On the basis of our current findings, we conclude that splicing of theSh1 intron is integral to enhancement, and we hypothesize that transcript modifications triggered by the T-rich motif and splicing may link the mRNA with the trafficking system of the cell.
Marketing principles in the application of e‐commerce
Authors: Hughes Tim John
Published: October 2002

E‐commerce has been much hyped as a potentially transformational force in many industries, and financial services is an industry where its impact is expected to be particularly strong. In this qualitative research four case studies have been developed, from a series of in‐depth interviews, to investigate the way some UK financial services organisations have responded to this innovation. By taking a broad perspective, from a range of managers across a number of disciplines, this study particularly focuses on the application of marketing principles, on an organisation wide basis, to the new challenges presented by e‐commerce. E‐commerce can be seen to present considerable structural and cultural challenges for large established organisations. It is also potentially changing a number of aspects of customer management. Significant areas for further research are identified.
Coordinate Regulation of Transcription and Splicing by Steroid Receptor Coregulators
Authors: Auboeuf Didier , Hönig Arnd , Berget Susan M. , O'Malley Bert W.
Published: October 2002

Recent observations indicating that promoter identity influences alternative RNA-processing decisions have created interest in the regulatory interactions between RNA polymerase II transcription and precursor messenger RNA (pre-mRNA) processing. We examined the impact of steroid receptor–mediated transcription on RNA processing with reporter genes subject to alternative splicing driven by steroid-sensitive promoters. Steroid hormones affected the processing of pre-mRNA synthesized from steroid-sensitive promoters, but not from steroid-unresponsive promoters, in a steroid receptor–dependent and receptor-selective manner. Several nuclear receptor coregulators showed differential splicing effects, suggesting that steroid hormone receptors may simultaneously control gene transcription activity and exon content of the product mRNA by recruiting coregulators involved in both processes.
Penicillamine as a ligand in the catalytic asymmetric reduction of ketones
Authors: Hanessian Stephen , Jnoff Eric , Griffin Andrew M
Published: October 2002

Amino acids derived from D-penicillamine and thiazolidines were studied as ligands for the catalytic asymmetric reduction of ketones with borane. Enantioselectivities up to 83% ee were observed.Key words: asymmetric reduction, penicillamine, thiazolidine, amino acid.
The activation of fibroblast growth factors by heparin: Synthesis and structural study of rationally modified heparin-like oligosaccharides
Authors: Ojeda Rafael , Angulo Jesús , Nieto Pedro M , Martín-Lomas Manuel
Published: October 2002

Heparin-like hexasaccharide 3 and octasaccharide 4 have been synthesized using a convergent block strategy and their solution conformations have been determined by NMR spectroscopy. Both oligosaccharides contain the basic structural motif of the regular region of heparin but have been constructed as to display negatively charged sulfate groups only on one side of their solution helical structures. This charge distribution along the saccharide chain has been designed to get insight into the proposed mechanism for fibroblast growth factors (FGFs) activation that involves heparin-induced FGF dimerization.Key words: heparin oligosaccharides, synthesis design, conformational analysis, FGF activation.
Carbohydrate-antibody interactions by NMR for a13C-labelled disaccharide ligand
Authors: Uhrín Duan , Prasad A.V Krishna , Brisson Jean-Robert , Bundle David R
Published: October 2002

Incorporation of a13C label into a carbohydrate ligand, methyl 3-O-(3,6-dideoxy-α-D-xylohexopyranosyl)-2-O-methyl-α-D-mannopyranoside permitted by NMR spectroscopy the study of its binding to the Fab from a monoclonal antibody, Se 155-4. The signals of the free and bound form were observed in the13C spectrum of the carbohydrate-protein complex. The dissociation rate constants were consequently determined by full lineshape analysis of the13C spectrum. Comparison with simplified analyses relying only on the linewidth of the1H and13C signals of the free ligand were made and the justifications of underlying assumptions used in these analyses were discussed. For1H NMR, the protein resonances were purged with a13C filter to observe only the ligand resonances and NOEs between the ligand and the protein.Key words: carbohydrate, binding, NMR, C-13 label, chemical exchange.
Anomeric effects of sulfones
Authors: Chen Guangwu , Franck Richard W , Yang Guangli , Blumenstein Michael
Published: October 2002

The anomeric effect of the sulfone group in tetrahydropyrans has been determined. The value is >2 kcal mol1, which is larger than the A-value of a methyl group but less than the A-value of the sulfone in a tetrahydropyran. Hence, in an unsubstituted tetrahydropyranyl sulfone, the equatorial conformer predominates, whereas in a properly substituted methyltetrahydropyranyl sulfone, an axial sulfone is preferred over an axial methyl group.Key words: sulfone, tetrahydropyran, anomeric effect.
Cyclodextrin-, UV-, and high pH-induced fluorescence enhancement of the pesticide azinphos-methyl: Applications to its trace analysis
Authors: Wagner Brian D , Sherren Adam C , Rankin Matthew A
Published: October 2002

Various methods for the enhancement of the fluorescence of the pesticide azinphos-methyl are reported. The addition of hydroxypropyl-β-cyclodextrin was found to moderately enhance the fluorescence by a factor of three, presumably via inclusion of the pesticide into the cyclodextrin cavity. This complexation was found to occur with an association constant of 690 ± 140 M1. This enhancement was found to be too low to be useful in a fluorescence-based analytical method for this pesticide. Exposure of azinphos-methyl to UV light was also found to result in enhanced fluorescence, with much larger enhancement than in the case of addition of cyclodextrins. This enhancement was presumed to occur via photolysis of azinphos-methyl to a more fluorescent photoproduct. However, the difficulty of providing a constant UV dosage prevents its useful application as a fluorescence-based analytical method. Finally, it was found that base hydrolysis of azinphos-methyl resulted in a very large fluorescence enhancement. Although this enhancement was previously reported in the literature, it was found that contrary to the published reports, the hydrolysis occurred rapidly at room temperature, with no need for carrying out the reaction at increased temperature. Fluorescence enhancements of a factor of 300 were obtained by simply adding the appropriate amount of an aqueous NaOH solution to the aqueous azinphos-methyl sample. This procedure was used as the basis of a simple fluorescence-based analytical method for azinphos-methyl in water, with excellent linear calibration curves obtained down to concentrations of 5 ppb.Key words: fluorescence spectroscopy, pesticides, azinphos-methyl, fluorescence enhancement, hostguest inclusion.
Growth responses of subalpine fir to climatic variability in the Pacific Northwest
Authors: Peterson David W , Peterson David L , Ettl Gregory J
Published: October 2002

We studied regional variation in growth-limiting factors and responses to climatic variability in subalpine forests by analyzing growth patterns for 28 tree-ring growth chronologies from subalpine fir (Abies lasiocarpa (Hook.) Nutt.) stands in the Cascade and Olympic Mountains (Washington and Oregon, U.S.A.). Factor analysis identified four distinct time series of common growth patterns; the dominant growth pattern at any site varied with annual precipitation and temperature (elevation). Throughout much of the region, growth is negatively correlated with winter precipitation and spring snowpack depth, indicating that growth is limited primarily by short growing seasons. On the driest and warmest sites, growth is negatively correlated with previous summer temperature, suggesting that low summer soil moisture limits growth. Growth patterns in two regions were sensitive to climatic variability associated with the Pacific Decadal Oscillation, apparently responding to low-frequency variation in spring snowpack and summer soil moisture (one negatively, one positively). This regional-scale analysis shows that subalpine fir growth in the Cascades and Olympics is limited by different climatic factors in different subregional climates. Climategrowth relationships are similar to those for a co-occurring species, mountain hemlock (Tsuga mertensiana (Bong.) Carrière), suggesting broad biogeographic patterns of response to climatic variability and change by subalpine forest ecosystems in the Pacific Northwest.
Post-wildfire seedbeds and tree establishment in the southern mixedwood boreal forest
Authors: Charron I , Greene D F
Published: October 2002

We studied the post-wildfire establishment of jack pine (Pinus banksiana Lamb.), black spruce (Picea mariana (Mill.) BSP), and white spruce (Picea glauca (Moench) Voss) in the southern mixedwood boreal forest of Saskatchewan, Canada. The major objective of the study was to determine the influence of post-wildfire seedbed types on the juvenile survivorship of trees. Through a combination of permanent plots and sowing experiments, we demonstrated that mineral soil, thin Polytrichum Hedw. moss, and humus are much more favorable than the organic fermentation (Of) and litter seedbeds. We also show that differences among seedbeds are significantly more important than differences among species. In addition, the first year of a cohort has the highest rate of mortality, about 85% on mineral and humus seedbeds and 98% on Of seedbeds; differences in age-specific survivorship between seedbeds become muted by the end of the second year, and survivorship rates approach 1 by the end of the third summer. Finally, age structures showed that germination rates of black spruce and jack pine were very low the initial summer of the fire; that there was a peak in recruitment in the first post-fire summer; and that by the fourth year the recruitment declined to nearly zero.
AUXILIARY FIELD METHODS FOR THE SIMULATION OF QUANTUM COMPUTATION CIRCUITS
Authors: MATUTTIS HANS-GEORG , FISCHER KURT , ITO NOBUYASU , ISHIKAWA MASAMICHI
Published: October 2002

One obstacle in the simulation of quantum circuits is the high dimension of the Hilbert space. Using auxiliary field decompositions known from many-particle simulation, we can transform the mathematical description of the quantum circuit into a combination low-dimensional product states which can be sampled using Monte Carlo techniques. We demonstrate the method using Simon's algorithm for the detection of the period of a function.
POSITRON ANNIHILATION IN SiC
Authors: AMRANE N.
Published: October 2002

Valence electron and positron charge densities in SiC are obtained from wave functions derived in a model pseudopotential bandstructure calculation. It is observed that the positron density is maximum in the open interstices and is excluded not only from the ion cores but also, to a considerable degree, from the valence bonds. Electron–positron momentum densities are calculated for the (001–110) plane. The results are used to analyze the positron effect in large gap semiconductors.
A NO-GO THEOREM FOR de SITTER COMPACTIFICATIONS?
Authors: HARI DASS N. D.
Published: October 2002

A general framework for studying compactifications in supergravity and string theories was introduced by Candelas, Horowitz, Strominger and Witten1. This was further generalised to take into account the warp factor by de Wit, Smit and Hari Dass2. Though the prime focus of the latter was to find solutions with nontrivial warp factors (shown not to exist under a variety of circumstances), it was shown there that de Sitter compactifications are generically disfavoured (see also3). In this note we place these results in the context of a revived interest in de Sitter spacetimes.
SUPPRESSION OF SUPERCONDUCTIVITY BY Ni AND HOLE-DOPING EFFECT OF Ca IN (Y1-yCay)Ba2Cu3-xNixO7-δ
Authors: DEAC IOSIF G.
Published: October 2002

The superconducting and normal behavior of ( Y 1-y Ca y) Ba 2( Cu 3-x Ni x) O 7-δ compounds were investigated by using electrical resistivity and ac susceptibility measurements. For the samples with y = 0, Tc decrease from 91 K to 68 K as the level of Ni doping x increases from 0.0 to 0.25. The conduction mechanism of electrons appears to follow a crossover from a purely metallic regime to a semiconducting regime as the Ni content increases, i.e. for x ≥ 0.15. Ca incorporation in the YBa 2 Cu 2.85 Ni 0.15 O 7-δ samples, is manifested in the metallic behavior (of these samples), and the Tc decreases further to 72 K (for y = 0.05). The transition temperature of the Ni-Ca-doped samples, passes through a broadened maximum at 76 K (for y = 0.2) and then it decreases again. The co-substitution of calcium tends to counteract some of the effect induced by Ni, restoring the linear ρ - T regime and reducing the transition width, but it cannot recover the decrease of the critical temperature.
HOX11L2 expression defines a clinical subtype of pediatric T-ALL associated with poor prognosis
Authors: Ballerini Paola , Blaise Annick , Busson-Le Coniat Maryvonne , Su Xin Ying , Zucman-Rossi Jessica , Adam Mircea , van den Akker Jacqueline , Perot Christine , Pellegrino Beatrice , Landman-Parker Judith , Douay Luc , Berger Roland , Bernard Olivier A.
Published: October 2002

The most frequent oncogenic activation events characterized in childhood T acute lymphoblastic leukemia (T-ALL) result in the transcriptional activation of genes coding for transcription factors. The main genes are TAL1/SCL, a member of the basic region helix-loop-helix gene family, and HOX11L2, a member of the homeobox-containing protein family. To gain insight into the pathogenesis of this type of hematologic malignancy, we analyzed 28 T-ALL samples. SIL-TAL1/SCL fusion was detected in 6 patients; expression of HOX11L2 was observed in 6 patients and of HOX11 in 3 patients. With one exception, these activations did not occur simultaneously in the same patients, and they allowed the subclassification of 50% of the patients.SIL-TAL1 fusion was detected in association withHOX11 expression in one patient and with a t(8;14) (q24;q11) in another. High expression of LYL1,LMO2, or TAL1 was observed mainly in samples negative for HOX11L2 expression. HOX11L1 andHOX11 expression were observed in one instance each, in the absence of detectable chromosomal abnormality of their respective loci, on chromosomes 2 and 10, respectively. HOX11L2 expression was associated with a chromosome 5q abnormality, the location of theHOX11L2 locus in each case tested. Finally, our data show that HOX11L2 expression was a suitable marker for minimal residual disease follow-up and was significantly associated with relapse (P = .02).
Generation of minor histocompatibility antigen HA-1–specific cytotoxic T cells restricted by nonself HLA molecules: a potential strategy to treat relapsed leukemia after HLA-mismatched stem cell transplantation
Authors: Mutis Tuna , Blokland Els , Kester Michel , Schrama Ellen , Goulmy Els
Published: October 2002

Successful stem cell transplantation (SCT) across HLA barriers can be performed with cord blood, megadoses of stem cells, or with nonmyeloablative conditioning strategies. Because the HLA-mismatched transplants are often T-cell depleted, leukemia relapse rates are high. Treatment of relapsed leukemia after HLA-mismatched SCT is difficult. A novel potential strategy to treat relapsed leukemia after HLA-mismatched SCT is the use of patients' mismatched HLA molecules as antigen-presenting molecules to generate hematopoietic system–specific cytotoxic T cells (CTLs) from the stem cell donor. Adoptive transfer of these hematopoietic system–specific CTLs that are restricted by nonself HLA molecules may eliminate leukemia without affecting the patient's nonhematopoietic cells or donor hematopoietic cells. We investigated the feasibility of this strategy using the hematopoietic system–specific minor histocompatibility antigen HA-1, which is known to induce HLA-A2–restricted CTLs. HLA-A2−peripheral blood mononuclear cells were stimulated with HLA-A2+ T2 cells pulsed with synthetic HA-1 peptide or with dendritic cells transduced with the HA-1 cDNA. Tetrameric HLA-A2/HA-1 peptide complexes were used to monitor and enrich HA-1–specific CTLs. In the alloreactive cultures, HA-1–specific CTLs were enriched up to 7% by 3 rounds of antigen-specific stimulations and up to 87% by fluorescence-activated cell sorting of tetramer-positive T cells. The HA-1–specific CTLs showed specific lysis of the relevant target cells, including leukemic cells. Because the polyclonal CTL cultures also contained natural killer cells and allo–HLA-A2–specific CTLs, CTL clones were generated that showed the expected HA-1 specificity only. Thus, HA-1–specific CTLs restricted by nonself HLA-A2 molecules can be generated in an HLA-A2–mismatched setting.
The NFY transcription factor functions as a repressor and activator of the von Willebrand factor promoter
Authors: Peng Yiwen , Jahroudi Nadia
Published: October 2002

Human von Willebrand factor (VWF) gene sequences −487 to +247 function as an endothelial-specific promoter in vitro. Analysis of the activation mechanism of the VWF promoter has resulted in the identification of a number of cis-acting elements and trans-acting factors that regulate its activity. The GATA and Ets transcription factors were shown to function as activators of transcription, whereas NF1 and Oct1 were shown to repress transcription. We have reported the presence of another repressor element in exon 1 that interacted with a protein complex designated “R.” In the absence of NF1 binding, inhibition of this interaction resulted in promoter activation in nonendothelial cells. We have now identified the “R” protein complex as the NFY transcription factor. Using DNA methylation interference assay and base substitution mutation analysis, we show that NFY interacts with a novel DNA sequence corresponding to nucleotides +226 to +234 in the VWF promoter that does not conform to the consensus NFY binding sequence CCAAT. The VWF gene does contain a CCAAT element that is located downstream of the TATA box and we show that the NFY factor also interacts with this CCAAT element. Using antibodies specific against the A, B, and C subunits of NFY, we demonstrate that the NFY complexes interacting with the CCAAT sequence have a composition similar to that of the repressor binding to the first exon sequences. The results of mutation analysis and transfection studies demonstrated that the interaction of NFY with the upstream CCAAT element is required for VWF promoter activation. Based on these results, we hypothesize that NFY can function both as a repressor and activator of transcription and its function may be modulated through its DNA binding sequences.
Plasmodium yoelii uses the murine Duffy antigen receptor for chemokines as a receptor for normocyte invasion and an alternative receptor for reticulocyte invasion
Authors: Swardson-Olver Christine J. , Dawson Tracey C. , Burnett Robert C. , Peiper Stephen C. , Maeda Nobuyo , Avery Anne C.
Published: October 2002

Erythrocyte invasion by malaria parasites is a complex multistep process involving parasite and erythrocyte receptors. It is a critical stage in the parasite life cycle and, therefore, a logical step in which to intervene to prevent or ameliorate disease. Rodent models of malaria, commonly Plasmodium yoelii, are frequently used for studies of malaria pathogenesis. Little is known, however, about the invasion machinery of rodent malaria parasites. We have found previously that mice congenic for a region of chromosome 1, containing the Duffy antigen/receptor for chemokines (DARC), have different susceptibility to P yoelii infection. Because P vivax, a human parasite, and P knowlesi, a simian parasite, use DARC to enter human erythrocytes, we sought to identify the role of the murine DARC in P yoelii invasion. Using a novel in vivo invasion assay and DARC knock-out mice, we found that DARC knock-out normocytes (mature erythrocytes) had negligible levels of P yoelii invasion compared with wild-type normocytes, demonstrating that DARC is a receptor for invasion of murine erythrocytes. In contrast, DARC knock-out reticulocytes were invaded at a rate similar to that for wild-type reticulocytes. We conclude that there is a DARC- independent pathway for reticulocyte invasion. These findings represent the first identification of a murine malaria receptor on erythrocytes and the first determination that different pathways of invasion exist on normocytes and reticulocytes. Because we show conservation of host–receptor interactions between rodent and human malaria, we can now use this model to identify how immunity can interfere with the invasion process.
The chemokine receptor CCR7 and α4 integrin are important for migration of chronic lymphocytic leukemia cells into lymph nodes
Authors: Till Kathleen J. , Lin Ke , Zuzel Mirko , Cawley John C.
Published: October 2002

Malignant lymphocyte migration into lymph nodes is an important aspect of chronic lymphocytic leukemia (CLL), yet little is known about the processes involved. Here we demonstrate that CLL cells migrate across vascular endothelium in response to at least 3 chemokines, namely, CCL21, CCL19, and CXCL12. Moreover, transendothelial cell migration (TEM) in response to CCL21 and CCL19 was significantly higher for the malignant B cells of patients who had clinical lymph node involvement as compared with those of patients lacking such organomegaly. Furthermore, the expression of CCR7, the receptor for both CCL21 and CCL19, correlated with clinical lymphadenopathy, and blocking of CCR7 inhibited CLL cell TEM. By using immunohistochemistry we demonstrated that CCL21 and CCL19, but not CXCL12, are located in high endothelial venules and are, therefore, in an appropriate location to induce TEM. Regarding the adhesion receptors involved in TEM, α4 (most likely in association with β1) and αLβ2 were shown to be important in CLL cell TEM in vitro, but only the level of α4 expression correlated with the presence of clinical lymphadenopathy. The present studies are the first to shed light on the factors determining CLL cell entry into nodes and define the phenotype of circulating malignant cells likely to determine the pattern of lymph node enlargement in the disease.