bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel application of sRNA: Stimulation of ribosomal frameshifting: FIGURE 1.
Authors: OLSTHOORN R.C.L. , LAURS M. , SOHET F. , HILBERS C.W. , HEUS H.A. , PLEIJ C.W.A.
Published: October 2004

Small RNAs play an important role in regulation of gene expression in eukaryotic and eubacterial cells by modulating gene expression both at the level of transcription and translation. Here, we show that short complementary RNAs can also affect gene expression by stimulating ribosomal frameshifting in vitro. This finding has important implications for understanding the process of ribosomal frameshifting and for the potential application of small RNAs in the treatment of diseases that are due to frameshift mutations.
Genomic Expansion Across the Albumin Gene Family on Human Chromosome 4q Is Directional
Authors: Nishio Hitomi , Hamdi Hamdi K. , Dugaiczyk Achilles
Published: October 2004

The albumin gene family arose in a series of duplication events which gave rise to symmetry in its structure. The four genes are tandemly linked on human chromosome 4q in the order: 5′ ALB-5′ AFP-5′ ALF-5′ DBP-centromere, and their introns display a symmetrical and repetitive pattern that is shared by members of the gene family. These repetitive motifs provide an internal reference, allowing observations of evolutionary changes within a single line (human) of evolutionary descent. The four genes and three intergenic regions between them increase in size as they get closer to the centromere. An invasion by multiple repetitive DNA elements may account, in part, for this expansion.
Plasmin Produces an E-Cadherin Fragment That Stimulates Cancer Cell Invasion
Authors: Ryniers Filip , Stove Christophe , Goethals Marc , Brackenier Liesbeth , Noë Veerle , Bracke Marc , Vandekerckhove Joël , Mareel Marc , Bruyneel Erik
Published: October 2004

Matrix metalloproteases from the cell surface cleave an 80 kDa Ecadherin fragment (sECAD) that induces invasion of cancer cells into collagen type I and inhibits cellular aggregation. Conditioned media from MDCKts.srcCl2 cells at 40 C and 35 C, PCm.src5 and COLO-16 cells at 37 C contained spontaneously released sECAD; these 48 h old conditioned media were capable of inhibiting Ecadherin functions in a paracrine way. Here we show direct cleavage of the extracellular domain of Ecadherin by the serine protease plasmin. sECAD released by plasmin inhibits Ecadherin functions as evidenced by induction of invasion into collagen type I and inhibition of cellular aggregation. This functional inhibition by sECAD was reversed by aprotinin or by immunoadsorption on protein Sepharose 4 fast flow beads with antibodies against the extracellular part of Ecadherin. Our results demonstrate that plasmin produces extracellular Ecadherin fragments which regulate Ecadherin function in cells containing an intact Ecadherin/ catenin complex.
Interactions of Nitric Oxide and Peroxynitrite with Low-Density Lipoprotein
Authors: Rubbo H. , Trostchansky A. , Botti H. , Batthyány C.
Published: October 2004

Nitric oxide (NO) is a free radical species that diffuses and concentrates in the hydrophobic core of lowdensity lipoprotein (LDL) to serve as a potent inhibitor of lipid oxidation processes. Peroxynitrite (PN), the product of the diffusionlimited reaction between NO and superoxide (O2), represents a relevant mediator of oxidative modifications in LDL. The focus of this review is the analysis of interactions between NO and PN and its secondary reactions with oxygen radicals on LDL oxidation, which are relevant in the development of the early steps as well as progression of atherosclerosis. We propose that the balance between rates of PN and NO production, which greatly depends on oxidative stress processes within the vascular wall, will critically determine the final extent of oxidative LDL modifications leading or not to scavenger receptormediated LDL uptake and foam cell formation.
Analysis of the Structural Determinants for RNA Binding of the Human Protein AUF1/hnRNP D
Authors: Moraes Karen C.M. , Lee Wen Hwa , Kobarg Jörg
Published: October 2004

The protein AUF1/hnRNP D was one of the first factors identified that binds to the AUrich region of certain mRNAs and mediates their fast degradation. Here we describe experiments to address the structural determinants for the binding of AUF1 to the RNA by combining comparative molecular modeling with gel shift assays. From our model of the RNA binding region of AUF1 we predicted that it interacts with RNA predominantly through stacking interactions that do not provide basespecific recognition. Only two RNA positions bound by AUF1 show base preferences: one for pyrimidine bases and the second for a conserved adenine residue. Gel shift assays with a panel of RNA oligonucleotides largely confirmed these modelbased binding determinants. An alignment with proteins of the hnRNP family demonstrated that the amino acids involved in the stacking interactions are conserved whereas those that confer a basespecific recognition in AUF1 are variable.
Epoxysuccinyl Peptide-Derived Cathepsin B Inhibitors: Modulating Membrane Permeability by Conjugation with the C-Terminal Heptapeptide Segment of Penetratin
Authors: Schaschke Norbert , Deluca Dominga , Assfalg-Machleidt Irmgard , Höhneke Clara , Sommerhoff Christian P. , Machleidt Werner
Published: October 2004

Besides its physiological role in lysosomal protein
breakdown, extralysosomal cathepsin B has recently
been implicated in apoptotic cell death. Highly specific
irreversible cathepsin B inhibitors that are readily cellpermeant
should be useful tools to elucidate the effects
of cathepsin B in the cytosol. We have covalently
functionalised the poorly cellpermeant epoxysuccinyl
based cathepsin B inhibitor [RGlyGlyLeu(2S,
3S)tEpsLeuProOH; R=OMe] with the Cterminal
heptapeptide segment of penetratin (R=AhxArg
ArgNleLysTrpLysLysNH2). The high inhibitory potency
and selectivity for cathepsin B versus cathepsin
L of the parent compound was not affected by the conjugation
with the penetratin heptapeptide. The conjugate
was shown to efficiently penetrate into MCF-7
cells as an active inhibitor, thereby circumventing an
intracellular activation step that is required by other inhibitors,
such as the prodruglike epoxysuccinyl peptides
E64d and CA074Me.
Muscarinic Toxin-Like Proteins from Taiwan Banded Krait (Bungarus multicinctus) Venom: Purification, Characterization and Gene Organization
Authors: Chung C. , Wu B.-N. , Yang C.-C. , Chang L.-S.
Published: October 2004

Two novel proteins, BM8 and BM14, were isolated from Bungarus multicinctus (Taiwan banded krait) venom using the combination of chromatography on a SPSephadex C-25 column and a reversephase HPLC column. Both proteins contained 82 amino acid residues including 10 cysteine residues, but there were two amino acid substitutions at positions 37 and 38 (Glu37Ala38 in BM8; Lys37Lys38 in BM14). CD spectra and acrylamide quenching studies revealed that the gross conformation of BM8 and BM14 differed. In contrast to BM8, BM14 inhibited the binding of [3H]quinuclidinyl benzilate to the M2 muscarinic acetylcholine (mAchR) receptor subtype. Trinitrophenylation of Lys residues abolished the mAchRbinding activity of BM14, indicating that the Lys substitutions at positions 37 and 38 played a crucial role in the activity of BM14. The genomic DNA encoding the precursor of BM14 was amplified by PCR. The gene shared virtually identical structural organization with αneurotoxin and cardiotoxin genes. The intron sequences of these genes shared a sequence identity up to 84%, but the proteincoding regions were highly variable. These results suggest that BM8, BM14, neurotoxins and cardiotoxins may have originated from a common ancestor, and the evolution of snake venom proteins shows a tendency to diversify their functions.
An Efficient Method for the Preparation of Long Heteroduplex DNA as Substrate for Mismatch Repair by the Escherichia coli MutHLS System
Authors: Thomas E. , Pingoud A. , Friedhoff P.
Published: October 2004

We present a method that allows preparing long DNA containing defined mismatches without the use of gel electrophoretic or chromatographic purification steps. The preparation starts with the synthesis of two PCR products, which are identical except for those positions that will later form the mismatches. One of the PCR primers must be 5phosphorylated, such that in two separate reactions two PCR products are obtained, which are 5phosphorylated in one strand. After removal of the phosphorylated strands by λexonuclease, the resulting single strands are hybridized to form the mismatchcontaining heteroduplex. The application of this procedure is demonstrated for the analysis of the Escherichia coli MutHLS system.
Amylin-Induced Cytotoxicity Is Associated with Activation of Caspase-3 and MAP Kinases
Authors: Rumora L. , Hadzija M. , Bariic K. , Maysinger D. , Grubiic T. Zanic
Published: October 2004

Nanomolar concentrations of human amylin promote death of RINm5F cells in a time and concentrationdependent manner. Morphological changes of chromatin integrity suggest that cells are predominantly undergoing apoptosis. Human amylin induces significant activation of caspase-3 and strong and sustained phosphorylation of stressactivated protein kinases, cJun Nterminal kinase (JNK) and p38, that precedes cell death. Extracellular signalregulated kinase (ERK) activation was not concomitant with JNK and/or p38 activation. Activation of caspase-3 and mitogenactivated protein kinases (MAPKs) was detected by Western blot analysis. Addition of the MEK1 inhibitor PD 98059 had no effect on amylininduced apoptosis, suggesting that ERK activation does not play a role in this apoptotic scenario. A correlative inhibition of JNK activation by the immunosuppressive drug FK506, as well as a selective inhibition of p38 MAPK activation by SB 203580, significantly suppressed procaspase-3 processing and the extent of amylininduced cell death. Moreover, simultaneous pretreatment with both FK506 and SB 203580, or with the caspase-3 inhibitor AcDEVDCHO alone, almost completely abolished procaspase-3 processing and cell death. Thus, our results suggest that amylininduced apoptosis proceeds through sustained activation of JNK and p38 MAPK followed by caspase-3 activation.
Properties of Baculovirus Particles Displaying GFP Analyzed by Fluorescence Correlation Spectroscopy
Authors: Toivola J. , Ojala K. , Michel P.O. , Vuento M. , Oker-Blom C.
Published: October 2004

Recombinant baculovirus particles displaying green
fluorescent protein (GFP) fused to the major envelope
glycoprotein gp64 of the Autographa californica multicapsid
nucleopolyhedrovirus (AcMNPV) were characterized
by fluorescence correlation spectroscopy
(FCS). FCS detected Brownian motion of single, intact
recombinant baculovirus display particles with a diffusion
coefficient (D) of (2.89±0.74)10 8 cm2s 1 and
an apparent hydrodynamic radius of 83.35±21.22 nm.
In the presence of sodium dodecyl sulfate (SDS), Triton
X-100, and octylglucoside, the diffusion time was
reduced to the 0.2 ms range (D = 7.5710 7 cm2s 1),
showing that the fusion proteins were anchored in the
viral envelope. This allowed for a calculation of the
number of single gp64 fusion proteins incorporated in
the viral membrane. A mean value of 3.2 fluorescent
proteins per virus particle was obtained. Our results
show that FCS is the method of choice for studying
enveloped viruses such as a display virus with one
component being GFP.
Incorporation of 13C-Labeled Coniferyl Alcohol into Developing Ginkgo biloba L. Lignin Revealed by Analytical Pyrolysis and CuO Oxidation in Combination with Isotope Ratio Monitoring-Gas Chromatography-Mass Spectrometry
Authors: Eglinton T. I. , Goñi M. A. , Boon J. J. , Hage E. R. E. van der , Terashima N. , Xie Y.
Published: October 2004

A suite of four samples of xylem tissue from Ginkgo (Ginkgo biloba L.) shoots grown in a medium containing
coniferin 13C-labeled at differing side-chain carbon atoms were studied using thermal and chemical
degradation methods in combination with molecular-level isotopic analyses. The aims of the study
were threefold: (1) to verify conclusions drawn from Nuclear Magnetic Resonance experiments previously
performed on the same tissue samples, (2) to investigate degradation mechanisms and (3) to quantify
the proportion of labeled material in each sample.

Isotopic analysis of specific degradation products revealed the presence of the label exclusively within
lignin-derived (phenolic) products and that the label is retained in its original position on the side-chain.
These two results clearly indicate that there is no “scrambling” of carbon atoms as a result of thermal
or chemical degradation, and thus lend strong support to analytical pyrolysis and chemolysis as
viable approaches for structural investigations of the lignin macromolecule. Indeed, the isotopic enrichment
of specific degradation products provides new evidence for certain types of linkages within the
lignin polymer.

The distribution and isotopic composition of the degradation products also strongly suggest an origin
from newly-formed lignin as opposed to DHP-type products or unreacted substrate. As such, the data
provides added confidence in the selective labeling approach for elucidation of the structure and biosynthesis
of lignin. Isotopic mass balance calculations reveal that certain pyrolysis and CuO oxidation products
show enhanced labeling which may be indicative of preferential incorporation of their specific precursors
into the growing lignin macromolecule or heterogeneous lignin deposition.
Atomic Force Microscopy (AFM) Investigation of Langmuir-Blodgett (LB) Films of Sugar Cane Bagasse Lignin
Authors: Constantino C. J. L. , Dhanabalan A. , Cotta M. A. , Pereira-da-Silva M. A. , Curvelo A. A. S. , Oliveira O. N.
Published: October 2004

The morphological features of Langmuir-Blodgett (LB) films of pure lignin extracted from sugar cane
bagasse and composites of lignin and cadmium stearate have been investigated using atomic force
microscopy (AFM). Results indicated that despite the non-amphiphilic nature of lignin and associated
relatively poor stability and transferability of the lignin monolayer, the surface of the film is smooth at
the micron level and comparable to that of LB films from typical amphiphilic compounds. Distinct
domain structures from lignin and cadmium stearate could be visualized in the composite LB film
even in one monolayer thick LB films. The mean surface roughness increases with increasing numbers of
layers.
Monitoring of Lignin and Hemicelluloses in Spent Cooking Liquor during Kraft Delignification
Authors: Bikova T. , Klevinska V. , Treimanis A.
Published: October 2004

A direct and rapid method for determining the average molecular weight (MW) and content of lignin and
hemicelluloses in spent cooking liquor by high performance size-exclusion chromatography (HPSEC)
using a cartridge glass column and 2.5 mM NaOH as an eluent was developed. A Uv290 detector in line
with a RI detector was applied to characterise lignin and hemicelluloses, respectively, from liquor during
the kraft cooking of grey and black alder wood. During the main delignification stage, the concentration
of high-MW wood components in liquor changed through the maximum. The MW values of hemicelluloses
in the liquor decreased to DPn = 30 ± 5 and DPw = 55 ± 5. The M̄
n and M̄
w of lignin in spent
kraft cooking liquor during the main and final delignification stages did not exceed 3000 and 5000, respectively.
Preparation of Wood with Thermoplastic Properties, Part 1. Classical Synthesis
Authors: Timar Maria Cristina , Mihai Maria Daniela , Maher Kevin , Irle Mark
Published: October 2004

Aspen wood (Populus tremula) as sawdust was chemically modified through a two-step procedure: esterification
with maleic anhydride and subsequent oligoesterification with glycidyl methacrylate and maleic
anhydride. Chemical analyses and infra-red spectroscopy revealed the differences in the chemical
composition and structure of wood as a result of this treatment. These changes were also reflected by a
hygroscopicity test and thermal analyses such as thermogravimetry and thermomechanical analysis. The
esterified wood showed an increased hygroscopicity and a decreased thermal stability compared to
unmodified wood. In contrast, the oligoesterified wood demonstrated a reduced hygroscopicity and a
comparable thermal stability up to about 200°C. The thermomechanical analysis of oligoesterified wood
clearly showed a significant softening phenomenon in the range 80–140°C, a direct evidence of the thermoplastic
properties gained by this chemical modification.
Confirmation of the Presence of Formaldehyde and N-(Methylene)morpholinium Cations as Reactive Species in the Cellulose/NMMO/Water System by Trapping Reactions
Authors: Potthast A. , Rosenau T. , Kosma P. , Chen C.-L. , Gratzl J. S.
Published: October 2004

The presence of formaldehyde (4) in solutions of cellulose in N-methylmorpholine-N-oxide (NMMO, 1)
has been shown by trapping formaldehyde as dimedone adduct 8 in a two-phase system. o-Dichlorobenzene
was used as an inert solvent to extract the trapping product as soon as it had formed.

Morpholine is a degradation product of NMMO and is always present in systems containing NMMO.
Formaldehyde can react with morpholine to form an intermediate carbenium-iminium ion, N-(methylene)
morpholinium (6). The occurrence of 6 in the system cellulose/NMMO was demonstrated by trapping
this intermediate in a Mannich type reaction with 2-acetonaphthone (9). Both formaldehyde and N-(methylene)morpholinium cations are highly reactive species readily undergoing further reactions with
nucleophiles. These processes might contribute to the observed discoloration of the reaction mixture, and
might also be responsible for the decomposition of NMMO that is inducible by carbenium-iminium ions.
Removal of Phenolic Hydroxyl Groups in Lignin Model Compounds and Its Effect on Photostability
Authors: Hu Thomas Q. , Cairns Graham R. , James Brian R.
Published: October 2004

The phenolic hydroxyl groups in the lignin model compounds, 2-methoxy-4-propylphenol and 4-hydroxy-3-methoxyacetophenone, were removed by first converting the hydroxyl groups to the trifluoromethanesulfonates
(triflates) and then cleaving the triflate substituents via catalytic hydrogen transfer.
The products, 1-methoxy-3-propylbenzene and 3-methoxyacetophenone, were characterized by 1H and
13C NMR, mass spectrometry and elemental analyses. The effect of the removal of the phenolic groups
on the photostability of the model compounds was evaluated by impregnating the compounds into Whatman
filter paper sheets, and subjecting them to an accelerated yellowing experiment in a UV chamber.
The removal of the phenolic groups resulted in a significant yellowing inhibition, with a higher photostabilizing
effect than methylation or acetylation of the hydroxyl, particularly for the model compound
without an α-carbonyl group.
Chlorinated Phenolic Compounds in Bleaching Filtrates from a Mixed Eucalyptus and Acacia Pulp Using Different Sequences
Authors: Furtado João L. F. , Peralba Maria do Carmo R. , Zini Cláudia A. , Caramão Elina B.
Published: October 2004

Bench filtrates from three-stage conventional bleaching sequences (CEoD) with substitution degrees of
chlorine by chlorine dioxide in the first stage equals to zero, 25%, 75% and 100% have been analysed
for their content of chlorinated phenolic compounds (CPCs). Alternatively, CPCs filtrates content of an
AZEoPD sequence were also determined. A cellulose pulp obtained from a mixture of 85% Eucalyptus
saligna (young trees) and 15% Acacia mearnsii delignified with oxygen (kappa number 10.0) was
employed in all bleaching tests. Levels of CPCs were determined by using an in situ acetylation method
followed by GC/ECD technique. GC/MS of bleaching filtrates was employed in qualitative analyses.
CPCs content in filtrates and the Kovacs' equivalent toxicity for the total filtrates of the studied bleaching
sequences are presented. The lowest content of CPCs was found in AZEoPD filtrates, as expected
due to the utilised bleaching agents. CPCs were not detected in the filtrates of stage D from the AZEoPD
sequence probably due to the low lignin content of the pulp. Mixed filtrates of the sequence DEoD,
showed the lowest CPCs content among conventional bleachings. Results are in accordance with those
found in the literature for hardwood and softwood pulp. The equivalent toxicity in the sequences
Dc(75/25), DEoD and AZEoPD was found to be lower than the limit given by Kovacs to characterise
chronical toxicity.
Kinetic Studies on Oxidation of Veratryl Alcohol by Laccase-Mediator System. Part 1. Effects of Mediator Concentration
Authors: Balakshin Mikhail Yu. , Chen Chen-Loung , Gratzl Josef S. , Kirkman Adrianna G. , Jakob Harald
Published: October 2004

Kinetics of the laccase-catalyzed oxidation of veratryl alcohol with dioxygen in the presence of 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diamonium salt (ABTS), the mediator, were studied
to elucidate the possible reaction mechanism and the role of the mediator in this reaction. The reaction
follows a pseudo-first order reaction law. The first order rate constant (κ) is dependent on the Mediator/Substrate (M/S) ratio and has a maximum at M/S molar ratio of 0.15. The kinetic studies show
that the mechanism of veratryl alcohol oxidation with dioxygen-laccase-ABTS is rather complex and
includes different reaction pathways. The mediator is involved in competitive reactions. It has been suggested
that at low mediator concentration, the veratryl alcohol is oxidized via the laccase redox cycle.
The mediator acts mostly as a laccase activator at a M/S ratio lower than 0.15. With increasing ABTS
concentration with respect to the substrate concentration, ABTS acts increasingly as a cosubstrate competing
with the original substrate for active centers of the laccase. This results in inhibition of veratryl
alcohol oxidation in the enzyme cycle and increases the role of substrate oxidation by an oxidized
mediator.
Determination of Residual Stresses in Medium Density Fibreboard
Authors: Houts Jeroen van , Bhattacharyya Debes , Jayaraman Krishnan
Published: October 2004

Due to the moisture and temperature gradients developed during hot pressing of medium density fibre-board
(MDF), residual stresses occur within the board as it equilibrates to room conditions. It would be
extremely useful to measure these residual stresses and to determine their effects on board properties
such as moduli of elasticity and rupture in bending, internal bond strength and dimensional stability. In
this article two methods, namely dissection and hole drilling, have been adapted to measure residual
internal stress distributions in six different samples of industry produced MDF. The dissection method
involves cutting several pieces of MDF perpendicular to the thickness direction at different depths. The
residual stresses released by the dissection can be determined by measuring the curvatures of cut pieces
and knowing their elastic moduli. The hole drilling method, on the other hand, involves mounting three
strain gauges on the surface of a piece of MDF and drilling a hole to release residual stresses in close
proximity. The released stresses are manifested as strains in the forms of which can be measured in three
directions on the surface of the board.

A theoretical model for predicting residual stresses involving various parameters has been developed and
an excellent agreement with the experimental results from both the dissection and hole drilling methods
has been achieved. Linear moisture expansion coefficient appears to have the greatest influence on residual
stress. When compared against each other, the residual stresses measured by the hole drilling method
show some shortcomings towards the centre of the board. While all six of the MDF boards exhibited
similar trends in their residual stress distributions, significant differences were identified in the magnitudes
of residual stress measured. Finally, some preliminary results linking the residual stress with the
thickness swell of the samples and their surface densities have been presented.
Study of the System Wood – Coating Material. I. Wood – Liquid Coating Material
Authors: Liptáková Eva , Kúdela Jozef , Sarva Ján
Published: October 2004

This paper deals with the evaluation of wood—wetting process with coating materials on the basis of
interactions of surface forces on phase boundary. The obtained results are compared with the actual state
in the system wood—coating material. Primary ability of coating materials—spontaneous spreading over
the wood surface has been proved. There is also the secondary influence of rheological properties of coating
materials causing deformations of the phase boundary, non-perfect wetting of the wood surface and
apparent lowering of adhesion work. The influence of rheological properties has been expressed by using
the coefficient F the meaning of which follows from the comparison between results of adhesion work
computed according to modified Young-Dupré equation and of adhesion work determined on the basis
of the interactions of surface forces on the phase boundary between wood and liquid coating materials.
A direct dependence between the values of the coefficient F and coating materials viscosity has been
proved.
Time-Dependent Alterations in mRNA Expression of Brain Neuropeptides Regulating Energy Balance and Hypothalamo-Pituitary-Adrenal Activity after Withdrawal from Intermittent Morphine Treatment
Authors: Houshyar Hani , Manalo Sotara , Dallman Mary F.
Published: October 2004

Chronic stressors alter brain function and may leave traces after their relief. We used intermittent morphine treatment to examine the relationships between stress-induced changes in energy balance and hypothalamo-pituitary-adrenal (HPA) activity and the recovery thereafter. We studied the effects of morphine injections on energy balance, hormones and fat stores, brain neuropeptide expression, and the ACTH and corticosterone responses to restraint 12 hr after the final injection and 8 d later during recovery. Weight gain, food intake, and caloric efficiency decreased at morphine onset, and these were maintained throughout the morphine injections. At 12 hr, fat stores, leptin, insulin, and testosterone concentrations were reduced. Subsequently, body weight gain and food intake increased and caloric efficiency was above control during the final days. By the eighth recovery day, fat stores and peripheral hormones were no longer depressed. At 12 hr, an over-response of CRF mRNA to restraint occurred in the hypothalamus, similar to the facilitated ACTH and corticosterone responses. On day 8, the hypothalamic CRF mRNA response to restraint was still facilitated, opposite to inhibited ACTH responses. Hypothalamic CRF mRNA correlated highly with mesenteric fat weight in morphine-treated rats. We conclude that there is a prolonged recovery from chronic stressors involving interrelated changes in energy balance and HPA activity. Nonetheless, 8 d after withdrawal from morphine, rats still display facilitated central stress responses, similar to the HPA symptoms described in posttraumatic stress disorder patients. Repeated partial withdrawal associated with intermittent morphine treatment, compounded by complete withdrawal associated with termination of the treatment, is likely required for these metabolic and HPA derangements.
Localizing P300 Generators in Visual Target and Distractor Processing: A Combined Event-Related Potential and Functional Magnetic Resonance Imaging Study
Authors: Bledowski Christoph , Prvulovic David , Hoechstetter Karsten , Scherg Michael , Wibral Michael , Goebel Rainer , Linden David E. J.
Published: October 2004

Constraints from functional magnetic resonance imaging (fMRI) were used to identify the sources of the visual P300 event-related potential (ERP). Healthy subjects performed a visual three-stimulus oddball paradigm with a difficult discrimination task while fMRI and high-density ERP data were acquired in separate sessions. This paradigm allowed us to differentiate the P3b component of the P300, which has been implicated in the detection of rare events in general (target and distractor), from the P3a component, which is mainly evoked by distractor events. The fMRI-constrained source model explained >99% of the variance of the scalp ERP for both components. The P3b was mainly produced by parietal and inferior temporal areas, whereas frontal areas and the insula contributed mainly to the P3a. This source model reveals that both higher visual and supramodal association areas contribute to the visual P3b and that the P3a has a strong frontal contribution, which is compatible with its more anterior distribution on the scalp. The results point to the involvement of distinct attentional subsystems in target and distractor processing.
Prenatal Nicotine Exposure Alters Central Cardiorespiratory Responses to Hypoxia in Rats: Implications for Sudden Infant Death Syndrome
Authors: Neff Robert A. , Simmens Samuel J. , Evans Cory , Mendelowitz David
Published: October 2004

Maternal cigarette smoking and prenatal nicotine exposure are the highest risk factors for sudden infant death syndrome (SIDS). During hypoxia, respiratory frequency and heart rate transiently increase and subsequently decrease. These biphasic cardiorespiratory responses normally serve to prolong survival during hypoxia by reducing the metabolic demands of cardiac and respiratory muscles. However, exaggerated responses to hypoxia may be life threatening and have been implicated in SIDS. Heart rate is primarily determined by the activity of brainstem preganglionic cardioinhibitory vagal neurons (CVNs) in the nucleus ambiguus. We developed anin vitrorat brainstem slice preparation that maintains rhythmic inspiratory-related activity and contains fluorescently labeled CVNs. Synaptic inputs to CVNs were examined using patch-clamp electrophysiological techniques. Hypoxia evoked a biphasic change in the frequency of both GABAergic and glycinergic IPSCs in CVNs, comprised of an initial increase followed by a decrease in IPSC frequency. Prenatal exposure to nicotine changed the GABAergic response to hypoxia from a biphasic response to a precipitous decrease in spontaneous GABAergic IPSC frequency. This study establishes a likely neurochemical mechanism for the heart rate response to hypoxia and a link between prenatal nicotine exposure and an exaggerated bradycardia during hypoxia that may contribute to SIDS.
Biochemical, Ultrastructural, and Reversibility Studies on Huntingtin Filaments Isolated from Mouse and Human Brain
Authors: Díaz-Hernández Miguel , Moreno-Herrero Fernando , Gómez-Ramos Pilar , Morán María A. , Ferrer Isidro , Baró Arturo M. , Avila Jesús , Hernández Félix , Lucas José J.
Published: October 2004

Huntington's disease (HD) and eight additional inherited neurological disorders are caused by CAG triplet-repeat expansions leading to expanded polyglutamine-sequences in their respective proteins. These triplet-CAG repeat disorders have in common the formation of aberrant intraneuronal proteinaceous inclusions containing the expanded polyglutamine sequences. These aggregates have been postulated to contribute to pathogenesis caused by conformational toxicity, sequestration of other polyglutamine-containing proteins, or by interfering with certain enzymatic activities. Testing these hypotheses has been hampered by the difficulty to isolate these aggregates from brain. Here we report that polyglutamine aggregates can be isolated from the brain of the Tet/HD94 conditional mouse model of HD, by following a method based on high salt buffer homogenization, nonionic detergent extraction, and gradient fractionation. We then verified that the method can be successfully applied to postmortem HD brains. Immunoelectron microscopy, both in human and mouse samples, revealed that the stable component of the inclusions are mutant huntingtin-containing and ubiquitin-containing fibrils. Atomic-force microscopy revealed that these fibrils have a “beads on a string” morphology. Thus, they resemble thein vitroassembled filaments made of recombinant mutant-huntingtin, as well as the Aβ and α-synuclein amyloid protofibrils. Finally, by shutting down transgene expression in the Tet/HD94 conditional mouse model of HD, we were able to demonstrate that these filaments, although stablein vitro, are susceptible to revertin vivo,thus demonstrating that the previously reported reversal of ubiquitin-immunoreactive inclusions does not simply reflect disassembling of the inclusions into their constituent fibrils and suggesting that any associated conformational or protein-sequestration toxicity is also likely to revert.
Rapid, Activity-Induced Increase in Tissue Plasminogen Activator Is Mediated by Metabotropic Glutamate Receptor-Dependent mRNA Translation
Authors: Shin Chan Y. , Kundel Mitchell , Wells David G.
Published: October 2004

Long-term synaptic plasticity is both protein synthesis-dependent and synapse-specific. Therefore, the identity of the newly synthesized proteins, their localization, and mechanism of regulation are critical to our understanding of this process. Tissue plasminogen activator (tPA) is a secreted protease required for some forms of long-term synaptic plasticity. Here, we show tPA activity is rapidly increased in hippocampal neurons after glutamate stimulation. This increase in tPA activity corresponds to an increase in tPA protein synthesis that results from the translational activation of mRNA present at the time of stimulation. Furthermore, the mRNA encoding tPA is present in dendrites and is rapidly polyadenylated after glutamate stimulation. Both the polyadenylation of tPA mRNA and the subsequent increase in tPA protein is dependent on metabotropic glutamate receptor (mGluR) activation. A similar mGluR-dependent increase in tPA activity was detected after stimulation of a synaptic fraction isolated from the hippocampus, suggesting tPA synthesis is occurring in the synaptodendritic region. Finally, we demonstrate that tPA mRNA is bound by the mRNA-binding protein CPEB (cytoplasmic polyadenylation element binding protein-1), a protein known to regulate mRNA translation via polyadenylation. These results indicate that neurons are capable of synthesizing a secreted protein in the synaptic region, that mGluR activation induces mRNA polyadenylation and translation of specific mRNA, and suggest a model for synaptic plasticity whereby translational regulation of an immediate early gene precedes the increase in gene transcription.
Step‐Stress Testing
Authors: Gouno Evans
Published: October 2004

Step‐stress accelerated life test have been studied at least since the 1950s. The strategy consists in testing items successively under different levels of stresses. The main advantage of this strategy is to overcome the issue of selecting the proper level of stress that generates enough failures to make inference in classical accelerated life test where the stress is constant. It reduces test time and the variability of the failure times. Various types of data are obtained from step‐stress tests. According the nature of the basic assumptions, different statistical techniques can be used. The following work gives an overview of various approaches to handle step‐stress accelerated life test data.
CERESPlots
Authors: Berk Kenneth N. , Booth David E.
Published: October 2004

In a multiple linear regression, it is assumed that the dependence on each of the predictors is linear. The partial residual plot has been available as a diagnostic, but it can fail if there are nonlinear relationships among the predictors. The Mallows augmented partial residual plot is effective even if there are quadratic relationships among the predictors. Dennis Cook developed the CERES plot to show a curve in the relationship of the dependent variable to a predictor, in spite of any nonlinear relationships among the predictors.
Geographic Information Systems
Authors: Griffith Daniel A.
Published: October 2004

A geographic information system (GIS) is a computer hardware and software information system designed to capture, edit, manage, house, manipulate, analyze, and display georeferenced data. It comprises high‐resolution scientific visualization capabilities, large‐capacity electronic storage devices, efficient and effective structures for data storage and retrieval, high‐volume communication channels, specialized algorithms for data integration and reliability analysis, and specialized query languages. Its reference point is a digital map. The first GIS was developed by the Canadian government and implemented in 1964. A differentiating feature among GISs is whether the underlying map involves a raster or vector surface partitioning. Spatial statistics requires attribute data, a map, and the tagging of each data observation to a location on a map, items furnished by a GIS. A GIS also supplies a practical and useful way to reveal spatial and temporal relationships among data. The UCGIS is an organization whose mission is to serve as an effective unified voice for the community of GIS users.
Income and Wealth Distributions,Dagum System of
Authors: Dagum Camilo
Published: October 2004

This entry presents the Dagum generating system of income and wealth distributions from which can be derived the Dagum Type I, II, and III as well as other well‐known models, specified in the literature on income distribution. The supports of the Dagum Type I, II, and III models are (0, ∞), [0, ∞), and (y0, ∞),y0 > 0 respectively. This family of models has been further generalized to fit net wealth distributions with support (−∞, ∞). Eight basic properties are introduced to validate the income and wealth distribution models. The models are illustrated with applications to real‐life data; the fit of each is excellent, meeting the requirements of the eight properties retained as essential.
Rainfall, Landforms, and Streamflow
Authors: Troutman Brent M.
Published: October 2004

A wide variety of stochastic modeling procedures has been applied to rainfall, landforms, and streamflow. A representative selection of these procedures is reviewed in this article. Emphasis is placed on interesting features that pose a challenge to modeling, such as the intermittency of rainfall in both space and time, the discrete branching structure of channel networks, and small streamflow measurement samples necessitating regional analysis methods. In all three areas, traditional modeling notions are discussed and modern scaling approaches introduced. Dependence of streamflow on rainfall and landforms is discussed in the final section, and it is demonstrated how stochastic and physical process ideas come together in understanding the relationships among these areas.
Signal Processing, Selection Approach in
Authors: Chen Pinyuen , Panchapakesan S.
Published: October 2004

This article considers selection and ranking goals and techniques in studying the problems of simultaneous detection of signals at several sites and also estimating the number of signals.
Geostatistics
Authors: Wackernagel Hans
Published: October 2004

Geostatistics is an application of the theory of random functions to spatially distributed data. The methods, initially proposed by Matheron in mining and petroleum exploration, found their way back to mainstream statistics more than a decade ago. The geostatistical methodology can be subdivided into linear and multivariate geostatistics, nonstationary geostatistics, nonlinear geostatistics, geostatistical simulation.
Kurtosis
Authors: Zenga Michele
Published: October 2004

The interpretation of the kurtosis index β2proposed by Karl Pearson is first examined. The Moors' indexTbased on quantiles and some partial orderings of kurtosis (by Van Zwet, Laurence, and Loh) are presented. Zenga's new approach to kurtosis, working for symmetrical as well as for asymmetrical distribution, is introduced. This latter approach is based on the definition of a particular transformation increasing kurtosis; a kurtosis curve, for the left and the right side of a distribution, can thus be obtained.
Forensic Science, Statistics in
Authors: Aitken Colin G. G.
Published: October 2004

Forensic statistics requires careful consideration and weighing of scientific evidence under two opposing propositions, that of the defence and the other of the prosecution. In this entry, some of the important concepts and ideas that are practiced in forensic statistics are described and some considerations for future direction are also outlined.
Human Capital
Authors: Dagum Camilo
Published: October 2004

This entry deals with the concept of human capital and its monetary value estimation. The basic assumptions and limitations of the traditional prospective (actuarial) and retrospective (cost of production) methods are discussed.

A more efficient estimation procedure, the latent variable‐actuarial method, is presented and illustrated using information from the 1983 US Federal Reserve Board sample survey of income and wealth distribution. The main results obtained are the standardized value of each household HC latent variable, the average HC by age of the household heads, the average national HC, the monetary value of each household HC, and its size distribution.
Log‐Gamma Distribution
Authors: Chan Ping‐Shing
Published: October 2004

The density function of a log‐gamma distribution is given. Its moment generating function and hence the mean, variance, coefficients of skewness, and kurtosis are derived. Two other forms of the distribution under reparametrization are also given such that the normal distribution is included as a member of the distribution. Its relationship to the generalized gamma distribution will also be discussed
Sequential Order Statistics
Authors: Cramer Erhard
Published: October 2004

Sequential order statistics have been introduced in order to model effects of component failures on the reliability ofk‐out‐of‐nsystems. Aside from this interpretation, they are related to several other models of ordered random variables such as Pfeifer's record values and generalized order statistics.
Income Inequality Measures
Authors: Dagum Camilo
Published: October 2004

This study purports to present, analyze, and evaluate the following:

The income inequality measures (IIMs) proposed since Pareto and Gini and to derive their corresponding utility and disutility functions from the specification of a fundamental equation of income. Furthermore, a dual relationship between utility and disutility functions and between IIMs and social welfare functions are established.

The decomposition approach of the generalized entropy measure (GEM) and the Gini ratio showing the extreme limitations of GEM to meaningful account for the contribution of the between‐group inequalities.

The directional distance ratio (DDR) between binary combinations of income distributions showing that it is a better alternative to the decomposition approach, and unlike the latter, DDR offers sound policy implications.

The distance function between income distributions.
EmpiricalBayes
Authors: Datta Somnath
Published: October 2004

This article presents a brief overview of the empirical Bayes approach to statistical inference and decision problems. Various methods of constructing empirical Bayes procedures are discussed through illustrative examples. Its relationship to the compound decision problem and shrinkage estimation are also discussed.
Bayesian Networks
Authors: Castillo Enrique , Hadi Ali S.
Published: October 2004

Many practical applications require the specification of the joint probability density (JPD) of a large set of random variables. This task can be very difficult in practice. Bayesian and Markov networks are two graphically based models that make the specification of the JPD and the propagation of uncertainty simple and efficient because they exploit the conditional independence structure of the JPD. This entry deals with Bayesian networks, also known as Belief networks. Markov networks are discussed in another entry. Bayesian networks are defined and their usefulness is illustrated by examples of the two most commonly used Bayesian networks, namely, the multinomial and Gaussian networks. The questions about how Bayesian networks can be constructed, how Bayesian networks can be learnt from data, and how uncertainty can be propagated when new evidence becomes available are also discussed.
Markov Networks
Authors: Castillo Enrique , Hadi Ali S.
Published: October 2004

Many practical applications require the specification of the joint probability density (JPD) of a large set of random variables. This task can be very difficult in practice. Bayesian and Markov networks are two graphically based models that make the specification of the JPD and the propagation of uncertainty simple and efficient because they exploit the conditional independence structure of the JPD. This entry deals with Markov networks. Bayesian networks are discussed in another entry. Markov networks are defined and the questions about how Markov networks can be constructed, how Markov networks can be learnt from data, and how uncertainty can be propagated when new evidence becomes available are also discussed.
Functional Networks
Authors: Castillo Enrique , Hadi Ali S.
Published: October 2004

Functional networks (FNs) are a general framework useful for solving a wide range of problems in various fields. In FNs, the network structure is not necessarily a black box; it is derived from the reality being modeled, that is, it is design‐driven. Unlike in neural networks (NNs), the neural functions in FNs are true multiargument, and different for all neurons. In FNs, neural functions are learned instead of weights as in NNs. In addition, neural functions can be forced to output the same values, thus leading to a system of functional equations that impose strong conditions on the neuron functions and allow simplification of the topology. FNs are illustrated by an example of application.
Generalized Order Statistics
Authors: Kamps Udo
Published: October 2004

Order statistics and record values appear in many statistical applications and are widely used in statistical modeling and inference. Both models describe random variables arranged in ascending order of magnitude. Generalized order statistics provide a unified approach to a variety of models of ordered random variables with different interpretations, such as ordinary order statistics, sequential order statistics, progressively type II censored order statistics, record values,kth record values, and Pfeifer's records. These models can be effectively applied, for example, in reliability theory. Here, an order statistic represents the life length of somek‐out‐of‐nsystem, which is an important technical structure. For this application, sequential order statistics serve to describe influences of failures on the life‐length distributions of the remaining components. Record values are used in shock models, and they are closely connected with the occurrence times of some corresponding nonhomogeneous Poisson process, with some minimal repair scheme, and with the relevation transform. The distribution theory of generalized order statistics is established along the lines of ordinary order statistics. By this, we find that many well‐known properties of order statistics and record values are also valid for generalized order statistics. The results on generalized order statistics concern their distribution theory, relations and bounds for moments, characterizations of distributions, preservation of aging properties and stochastic ordering, extreme‐value theory, and statistical inference with respect to model and distribution parameters.
Antieigenvalues, Antieigenvectors
Authors: Khattree Ravindra
Published: October 2004

In this entry, the concepts of antieigenvalues and antieigenvectors are first introduced. Then, various statistical situations wherein these entities arise naturally are explained.