bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrospray Mass Spectrometry as a Technique for Elemental Analysis: Quantitative Aspects
Authors: Agnes George R. , Horlick Gary
Published: October 2005

The quantitative aspects of elemental electrospray mass spectrometry are investigated with particular emphasis on the factors affecting the ability to establish linear calibration curves. It is shown that linear calibration curves can be obtained for trace elements if the analyte signal is ratioed to the signal from a constant amount of a similarly charged electrolyte species. Linear calibration curves can be established over a concentration dynamic range of at least four orders of magnitude. The added component seems to function as a stabilizer and monitor of the electrospray process and as an internal standard. In certain cases, species generated by acidification of the solvent may be used as electrospray stabilizers.
Speciation of Ambient Sulfate Particulate Matter Using FT-IR-Based Absorption to Complement Wet Chemical and Thermal Speciation Measurements
Authors: McClenny W. A. , Krost K. J. , Daughtrey E. H. , Williams D. D. , Allen G. A.
Published: October 2005

The direct, nondestructive, infrared transmission measurement of fine particles (<2.5 μm) on Teflon® filters was successfully used to unambiguously identify and to quantify ammonium bisulfate in particle samples collected from the ambient air. The samples were collected at 10 L/min over 23 hours for 24 consecutive summer days (21 July-14 August) in 1991 in a rural setting near State College, PA. These measurements were combined with wet chemical measurements of the same samples to infer the partition of particulate sulfate as ammonium sulfate, ammonium bisulfate, and sulfate associated with excess free hydrogen ion. A second set of independent wet chemical measurements of samples taken during the same time period were included in the analysis. The evidence for particle reactions on the filter and of some neutralization of acid sulfate by ammonia during sample processing is examined. Highly variable sulfate speciation is observed, including sulfuric acid and ammonium sulfate without ammonium bisulfate. Subject to the current limitations of the technique, sulfate as ammonium sulfate, ammonium bisulfate, and sulfuric acid is estimated in the approximate proportions of 3.0:5.5:1 for the overall study.
Sex Differences in Hormonal Modulation of Anxiety Measured with Light-Enhanced Startle: Possible Role for Arginine Vasopressin in the Male
Authors: Toufexis Donna , Davis Carrie , Hammond Alexis , Davis Michael
Published: September 2005

Increased acoustic startle in the presence of bright ambient light, a phenomenon called light-enhanced startle (LES), is dependent on the bed nucleus of the stria terminalis. In contrast to gonadally intact male rats, LES was seen reliably in castrated male rats and in female rats, although it fluctuated significantly with reproductive state. Replacement with testosterone (T) or combined estradiol (E2) and dihydrotestosterone (DHT), but not with either E2 or DHT alone, attenuated LES in castrated rats. However, replacement with T or E2 in ovariectomized rats did not decrease LES. In contrast, no sex difference was seen in the central amygdala-dependent acquisition or expression of fear-potentiated startle. In addition, T did not reduce expression of fear-potentiated startle in castrated rats. T-replaced castrated males injected centrally with mixed arginine vasopressin (AVP) V1a/b receptor antagonists daily throughout the replacement period failed to show a reduction in the expression of LES. These data suggest that T attenuates LES, but not fear-potentiated startle, through a mechanism that may involve AVP.
Encoding of Movement Direction in Different Frequency Ranges of Motor Cortical Local Field Potentials
Authors: Rickert Jörn , de Oliveira Simone Cardoso , Vaadia Eilon , Aertsen Ad , Rotter Stefan , Mehring Carsten
Published: September 2005

Recent studies showed that the low-frequency component of local field potentials (LFPs) in monkey motor cortex carries information about parameters of voluntary arm movements. Here, we studied how different signal components of the LFP in the time and frequency domains are modulated during center-out arm movements. Analysis of LFPs in the time domain showed that the amplitude of a slow complex waveform beginning shortly before the onset of arm movement is modulated with the direction of the movement. Examining LFPs in the frequency domain, we found that direction-dependent modulations occur in three frequency ranges, which typically increased their amplitudes before and during movement execution: ≤4, 6–13, and 63–200 Hz. Cosine-like tuning was prominent in all signal components analyzed. In contrast, activity in a frequency band ≈30 Hz was not modulated with the direction of movement and typically decreased its amplitude during the task. This suggests that high-frequency oscillations have to be divided into at least two functionally different regimes: one ≈30 Hz and one >60 Hz. Furthermore, using multiple LFPs, we could show that LFP amplitude spectra can be used to decode movement direction, with the best performance achieved by the combination of different frequency ranges. These results suggest that using the different frequency components in the LFP is useful in improving inference of movement parameters from local field potentials.
A Reduced Number of Metabotropic Glutamate Subtype 5 Receptors Are Associated with Constitutive Homer Proteins in a Mouse Model of Fragile X Syndrome
Authors: Giuffrida Raffaella , Musumeci Sebastiano , D'Antoni Simona , Bonaccorso Carmela Maria , Giuffrida-Stella Anna Maria , Oostra Ben A. , Catania Maria Vincenza
Published: September 2005

Fragile X (FRAX) syndrome is a common inherited form of mental retardation resulting from the lack of fragile X mental retardation protein (FMRP) expression. The consequences of FMRP absence in the mechanism underlying mental retardation are unknown. Here, we tested the hypothesis that glutamate receptor (GluR) expression might be altered in FRAX syndrome. Initialin situhybridization and Western blotting experiments did not reveal differences in mRNA levels and protein expression of AMPA and NMDA subunits and metabotropic glutamate subtype 5 (mGlu5) receptors between control andFmr1knock-out (KO) mice during postnatal development. However, a detergent treatment (1% Triton X-100) revealed a selective reduction of mGlu5 receptor expression in the detergent-insoluble fraction of synaptic plasma membranes (SPMs) from KO mice, with no difference in the expression of NR2A, GluR1, GluR2/3, GluR4, and Homer proteins. mGlu5 receptor expression was also lower in Homer immunoprecipitates fromFmr1KO SPMs. Homer, but not NR2A, mGlu5, and GluR1, was found to be less tyrosine phosphorylated inFmr1KO than control mice. Our data indicate that, in FRAX syndrome, a reduced number of mGlu5 receptors are tightly linked to the constituents of postsynaptic density and, in particular, to the constitutive forms of Homer proteins, with possible consequent alterations in synaptic plasticity.
Overexpression of PrPCby Adenovirus-Mediated Gene Targeting Reduces Ischemic Injury in a Stroke Rat Model
Authors: Shyu Woei-Cherng , Lin Shinn-Zong , Chiang Ming-Fu , Ding Dah-Ching , Li Kuo-Wei , Chen Shih-Fen , Yang Hui-I , Li Hung
Published: September 2005

Prion diseases are induced by pathologically misfolded prion protein (PrPSc), which recruit normal sialoglycoprotein PrPCby a template-directed process. In this study, we investigated the expression of PrPCin a rat model of cerebral ischemia to more fully understand its physiological role. Immunohistochemical analysis demonstrated that PrPC-immunoreactive cells increased significantly in the penumbra of ischemic rat brain compared with the untreated brain. Western blot analysis showed that PrPCprotein expression increased in ischemic brain tissue in a time-dependent manner. In addition, PrPCprotein expression was seen to colocalize with neuron, glial, and vascular endothelial cells in the penumbric region of the ischemic brain. Overexpression of PrPCby injection of rAd (replication-defective recombinant adenoviral)-PGK (phosphoglycerate kinase)-PrPC-Flag into ischemic rat brain improved neurological behavior and reduced the volume of cerebral infarction, which is supportive of a role for PrPCin the neuroprotective adaptive cellular response to ischemic lesions. Concomitant upregulation of PrPCand activated extracellular signal-regulated kinase (ERK1/2) under hypoxia–reoxygenation in primary cortical cultures was shown to be dependent on ERK1/2 phosphorylation. During hypoxia–reoxygenation, mouse neuroblastoma cell line N18 cells transfected with luciferase rat PrPCpromoter reporter constructs, containing the heat shock element (HSE), expressed higher luciferase activities (3- to 10-fold) than those cells transfected with constructs not containing HSE. We propose that HSTF-1 (hypoxia-activated transcription factor), phosphorylated by ERK1/2, may in turn interact with HSE in the promoter of PrPCresulting in gene expression of the prion gene. In summary, we conclude that upregulation of PrPCexpression after cerebral ischemia and hypoxia exerts a neuroprotective effect on injured neural tissue. This study suggests that PrPChas physiological relevance to cerebral ischemic injury and could be useful as a therapeutic target for the treatment of cerebral ischemia.
Rapid Reshaping of Human Motor Generalization
Authors: Thoroughman Kurt A. , Taylor Jordan A.
Published: September 2005

People routinely learn how to manipulate new tools or make new movements. This learning requires the transformation of sensed movement error into updates of predictive neural control. Here, we demonstrate that the richness of motor training determines not only what we learn but how we learn. Human subjects made reaching movements while holding a robotic arm whose perturbing forces changed directions at the same rate, twice as fast, or four times as fast as the direction of movement, therefore exposing subjects to environments of increasing complexity across movement space. Subjects learned all three environments and learned the low- and medium-complexity environments equally well. We found that subjects lessened their movement-by-movement adaptation and narrowed the spatial extent of generalization to match the environmental complexity. This result demonstrated that people can rapidly reshape the transformation of sense into motor prediction to best learn a new movement task. We then modeled this adaptation using a neural network and found that, to mimic human behavior, the modeled neuronal tuning of movement space needed to narrow and reduce gain with increased environmental complexity. Prominent theories of neural computation have hypothesized that neuronal tuning of space, which determines generalization, should remained fixed during learning so that a combination of neuronal outputs can underlie adaptation simply and flexibly. Here, we challenge those theories with evidence that the neuronal tuning of movement space changed within minutes of training.
Calcium/Calmodulin-Dependent Protein Kinase II Alters Structural Plasticity and Cytoskeletal Dynamics inDrosophila
Authors: Andersen Ryan , Li Yimei , Resseguie Mary , Brenman Jay E.
Published: September 2005

Drosophiladendritic arborization (da) neurons contain subclasses of neurons with distinct dendritic morphologies. We investigated calcium/calmodulin-dependent protein kinase II (CaMKII) regulation of dendritic structure and dynamicsin vivousing optically transparentDrosophilalarvae. CaMKII increases the dynamic nature and formation of dendritic filopodia throughout larval development but only affects neurons that normally contain dendritic filopodia. In parallel, we examined the effects of Rac1 activity on dendritic structure to explore signaling specificity. In contrast to CaMKII activity, Rac1 does not alter filopodia stability but instead causesde novofilopodia formation on all da neurons. Although both mediators increase cytoskeletal turnover, measured by fluorescence recovery after photobleaching experiments, only CaMKII increases the dynamic nature of dendritic filopodia. CaMKII signaling thus appears to use mechanisms and machinery distinct from Rac1 signaling. This study illustrates a molecular means of uncoupling cytoskeletal regulation from morphological regulation. Our results suggest thatDrosophiladendritic filopodia may share some cytoskeletal regulatory mechanisms with mammalian dendritic filopodia. Furthermore, general dendrite cytoskeletal compartmentalization is conserved in multipolar neurons.
Configural Processing of Biological Motion in Human Superior Temporal Sulcus
Authors: Thompson James C. , Clarke Michele , Stewart Tennille , Puce Aina
Published: September 2005

Observers recognize subtle changes in the movements of others with relative ease. However, tracking a walking human is computationally difficult, because the degree of articulation is high and scene changes can temporarily occlude parts of the moving figure. Here, we used functional magnetic resonance imaging to test the hypothesis that the superior temporal sulcus (STS) uses form cues to aid biological movement tracking. The same 10 healthy subjects detected human gait changes in a walking mannequin in two experiments. In experiment 1, we tested the effects of configural change and occlusion. The walking mannequin was presented intact or with the limbs and torso apart in visual space and either unoccluded or occluded by a set of vertical white bars. In experiment 2, the effects of inversion and occlusion were investigated, using an intact walking mannequin. Subjects reliably detected gait changes under all stimulus conditions. The intact walker produced significantly greater activation in the STS, inferior temporal sulcus (ITS), and inferior parietal cortex relative to the apart walker, regardless of occlusion. Interestingly, STS and ITS activation to the upright versus inverted walker was not significantly different. In contrast, superior parietal lobule and parieto-occipital cortex showed greater activation to the apart relative to intact walker. In the absence of an intact body configuration, parietal cortex activity increased to the independent movements of the limbs and torso. Our data suggest that the STS may use a body configuration-based model to process biological movement, thus forming a representation that survives partial occlusion.
How Much Afterhyperpolarization Conductance Is Recruited by an Action Potential? A Dynamic-Clamp Study in Cat Lumbar Motoneurons
Authors: Manuel Marin , Meunier Claude , Donnet Maud , Zytnicki Daniel
Published: September 2005

We accurately measured the conductance responsible for the afterhyperpolarization (medium AHP) that follows a single spike in spinal motoneurons of anesthetized cats. This was done by using the dynamic-clamp method. We injected an artificial current in the neurons that increased the AHP amplitude, and we made use of the fact that the intensity of the natural AHP current at the trough of the voltage trajectory was related linearly to the AHP amplitude. We determined at the same time the conductance and the reversal potential of the AHP current. This new method was validated by a simple theoretical model incorporating AHP and hyperpolarization-activated (Ih) currents and could be applied when the decay time constant of the AHP conductance was at least five times shorter than the estimatedIhactivation time. This condition was fulfilled in 33 of 44 motoneurons. The AHP conductance varied from 0.3 to 1.4 μS in both slow- and fast-type motoneurons, which was approximately the same range as the input conductance of the entire population. However, AHP and input conductances were not correlated. The larger AHP in slow-type motoneurons was mainly attributable to their smaller input conductance compared with fast motoneurons. The likeness of the AHP conductance in both types of motoneurons is in sharp contrast to differences in AHP decay time and explains why slow- and fast-type motoneurons have similar gain.
Downregulation of Cytosolic Prostaglandin E2Synthase Results in Decreased Nociceptive Behavior in Rats
Authors: Hofacker Annette , Coste Ovidiu , Nguyen Hong-Van , Marian Claudiu , Scholich Klaus , Geisslinger Gerd
Published: September 2005

Nociception-evoked prostaglandin E2(PGE2) release in the spinal cord contributes considerably to the development of hyperalgesia and allodynia. Biosynthesis of PGE2involves the conversion of arachidonic acid to PGH2by cyclooxygenases (COXs), followed by an isomerization of PGH2to PGE2by PGE2synthases (PGESs). The roles of COX-1, COX-2, and the inducible microsomal PGES-1 have been studied in models of pain and inflammation. In contrast, in nociceptive processes, very little is known about the role of cytosolic PGES (cPGES), which has been described as being functionally coupled to COX-1. Here we show byin situhybridization and immunohistological analysis that COX-1 and cPGES are constitutively expressed in neuronal and non-neuronal cells of the dorsal and ventral horns in the spinal cord of adult rats. The protein levels of both enzymes were not regulated by nociceptive stimuli; however, reduction of cPGES in rat spinal cord with intrathecal application of cPGES antisense oligonucleotides reduced the nociceptive behavior in zymosan-evoked thermal hyperalgesia and in the formalin assay. The data indicate that cPGES plays an important role in mediating early responses during spinal nociceptive processing.
Hippocampal Inactivation Disrupts the Acquisition and Contextual Encoding of Fear Extinction
Authors: Corcoran Kevin A. , Desmond Timothy J. , Frey Kirk A. , Maren Stephen
Published: September 2005

In recent studies, inactivation of the dorsal hippocampus before the retrieval of extinguished fear memories disrupted the context-dependent expression of these memories. In the present experiments, we examined the role of the dorsal hippocampus in the acquisition of extinction. After pairing an auditory conditional stimulus (CS) with an aversive footshock [unconditional stimulus (US)], rats received an extinction session in which the CS was presented without the US. In experiment 1, infusion of muscimol, a GABAAreceptor agonist, into the dorsal hippocampus before the extinction training session decreased the rate of extinction. Moreover, when later tested for fear to the extinguished CS, all rats that had received hippocampal inactivation before extinction training demonstrated renewed fear regardless of the context in which testing took place. This suggests a role for the dorsal hippocampus in both acquiring the extinction memory and encoding the CS–context relationship that yields the context dependence of extinction. In experiment 2, inactivation of the dorsal hippocampus before testing also disrupted the context dependence of fear to the extinguished CS. In experiment 3, quantitative autoradiography revealed the boundaries of muscimol diffusion after infusion into the dorsal hippocampus. Together, these results reveal that the dorsal hippocampus is involved in the acquisition, contextual encoding, and context-dependent retrieval of fear extinction. Learning and remembering when and where aversive events occur is essential for adaptive emotional regulation.
Constitutive Secretion of Protease Nexin-1 by Glial Cells and Its Regulation by G-Protein-Coupled Receptors
Authors: Giau Ronald , Carrette Josiane , Bockaert Joël , Homburger Vincent
Published: September 2005

Extracellular serine proteases and their inhibitors (serpins) play a key role for synaptic plasticity in the developing and adult CNS. Serpins also counteract the extravasated proteases during brain injury. We studied the mechanisms by which one of the most important serpins, serpinE2 or protease nexin-1 (PN-1), is secreted by glial cells and how its secretion is regulated by extracellular signals. Using time-lapse videomicroscopy and biochemical methods, we demonstrate that PN-1 is constitutively secreted through small vesicles animated by a discontinuous movement using microtubules as tracks. The F-actin network underneath the plasma membrane acting as a barrier hindered PN-1 vesicle exocytosis. Vasointestinal/pituitary adenylate cyclase peptides and the G-protein activator mastoparan increased PN-1 secretion by disrupting the F-actin barrier. The receptor-mediated regulation of PN-1 constitutive secretion may be an important mechanism adapting extracellular proteolytic activity to synaptic activity.
Depression of Synaptic Transmission by Vascular Endothelial Growth Factor in Adult Rat Hippocampus and Evidence for Increased Efficacy after Chronic Seizures
Authors: McCloskey Daniel P. , Croll Susan D. , Scharfman Helen E.
Published: September 2005

In addition to its potent effects on vasculature, it has become clear that vascular endothelial growth factor (VEGF) has effects on both neurons and glia, and recent studies suggest that it can be neuroprotective. To determine potential mechanisms underlying this neuroprotection, recombinant human VEGF was bath applied to adult rat hippocampal slices, and both extracellular and intracellular recordings were used to examine intrinsic properties and synaptic responses of hippocampal principal neurons. Initial studies in area CA1 showed that VEGF significantly reduced the amplitude of responses elicited by Schaffer collateral stimulation, without influencing membrane properties. Similar effects occurred in CA3 pyramidal cells and dentate gyrus granule cells when their major glutamatergic afferents were stimulated. Because VEGF expression is increased after seizures, effects of VEGF were also examined in rats with recurrent spontaneous seizures. VEGF reduced spontaneous discharges in slices from these rats but had surprisingly little effect on epileptiform discharges produced by disinhibition of slices from control rats. These results demonstrate a previously unknown effect of VEGF on neuronal activity and also demonstrate a remarkable potency in the epileptic brain. Based on this, we suggest that VEGF or VEGF-related targets could provide useful endpoints to direct novel therapeutic strategies for epilepsy.
Lipopolysaccharide-Induced Inflammation Exacerbates Tau Pathology by a Cyclin-Dependent Kinase 5-Mediated Pathway in a Transgenic Model of Alzheimer's Disease
Authors: Kitazawa Masashi , Oddo Salvatore , Yamasaki Tritia R. , Green Kim N. , LaFerla Frank M.
Published: September 2005

Inflammation is a critical component of the pathogenesis of Alzheimer's disease (AD). Although not an initiator of this disorder, inflammation nonetheless plays a pivotal role as a driving force that can modulate the neuropathology. Here, we characterized the time course of microglia activation in the brains of a transgenic model of AD (3xTg-AD) and discerned its relationship to the plaque and tangle pathology. We find that microglia became activated in a progressive and age-dependent manner, and this activation correlated with the onset of fibrillar amyloidβ-peptide plaque accumulation and tau hyperphosphorylation. To determine whether microglial activation can exacerbate the pathology, we exposed young 3xTg-AD mice to lipopolysaccharide (LPS), a known inducer of CNS inflammation. Although amyloid precursor protein processing appeared unaffected, we find that LPS significantly induced tau hyperphosphorylation at specific sites that were mediated by the activation of cyclin-dependent kinase 5 (cdk5) through increased formation of the p25 fragment. We further show that administration of roscovitine, a selective and potent inhibitor of cdk5, markedly blocked the LPS-induced tau phosphorylation in the hippocampus. Therefore, this study clearly demonstrates that microglial activation exacerbates key neuropathological features such as tangle formation.
Differential Roles of Nuclear and Cytoplasmic Cyclin-Dependent Kinase 5 in Apoptotic and Excitotoxic Neuronal Death
Authors: O'Hare Michael J. , Kushwaha Neena , Zhang Yi , Aleyasin Hossein , Callaghan Steven M. , Slack Ruth S. , Albert Paul R. , Vincent Inez , Park David S.
Published: September 2005

Cyclin-dependent kinase 5 (cdk5) is a member of the cyclin-dependent kinase family whose activity is localized mainly to postmitotic neurons attributable to the selective expression of its activating partners p35 and p39. Deregulation of cdk5, as a result of calpain cleavage of p35 to a smaller p25 form, has been suggested to be a central component of neuronal death underlying numerous neurodegenerative diseases. However, the relevance of cdk5 in apoptotic death that relies on the mitochondrial pathway is unknown. Furthermore, evidence that cdk5 can also promote neuronal survival has necessitated a more complex understanding of cdk5 in the control of neuronal fate. Here we explore each of these issues using apoptotic and excitotoxic death models. We find that apoptotic death induced by the DNA-damaging agent camptothecin is associated with early transcription-mediated loss of p35 and with late production of p25 that is dependent on Bax, Apaf1, and caspases. In contrast, during excitotoxic death induced by glutamate, neurons rapidly produce p25 independent of the mitochondrial pathway. Analysis of the localization of p35 and p25 revealed that p35 is mainly cytoplasmic, whereas p25 accumulates selectively in the nucleus. By targeting a dominant-negative cdk5 to either the cytoplasm or nucleus, we show that cdk5 has a death-promoting activity within the nucleus and that this activity is required in excitotoxic death but not apoptotic death. Moreover, we also find that cdk5 contributes to pro-survival signaling selectively within the cytoplasm, and manipulation of this signal can modify death induced by both excitotoxicity and DNA damage.
Bestimmung der Drahtvorschubgeschwindigkeit beim Schweißen mittels optischer Messverfahren und Waveletmethoden (Optical Measurement of Wire Speed in Welding Processes Using Wavelets)
Authors: Matthes Klaus-Jürgen , Kohler Thomas
Published: September 2005

Bei heute eingesetzten Systemen zur Drahtvorschubgeschwindigkeitsmessung beim Schweißen wurden Abweichungen bis 30% ermittelt. Es stand das Ziel, auf der Basis von optischen 2D-Sensoren eine Messeinrichtung zu entwickeln, welche echtzeitfähig arbeitet. Zur Verarbeitung der anfallenden großen Datenmengen kommen Wavelets zur Anwendung. Der Messfehler konnte für Stahl- und Kupferwerkstoffe deutlich unter 10% gesenkt werden.
Neue Formalismen zum Schätzen von Messunsicherheiten – Ausgleich nach kleinsten Quadraten (A new Formalism for the Estimation of Measurement Uncertainties – Least Squares Adjustment)
Authors: Grabe Michael
Published: September 2005

In zwei vorangehenden Artikeln wurde ein zum ISO-Guide alternatives Fehlermodell diskutiert. Der vorliegende Beitrag überträgt letzteres auf die Methode der kleinsten Quadrate. Dabei zeigt sich, dass die minimierte Summe der Residuenquadrate die ihr konventionell zugeschriebenen statistischen Eigenschaften verliert, das Gauß-Markoff’sche Theorem zusammenbricht und in Konsequenz dessen die Methode der kleinsten Quadrate nicht mehr in der Lage ist, so genannte „Optimal-Schätzer“ bereitzustellen.

Die Arbeit stellt einen Formalismus vor, der die wahren Werte der Messgrößen zuverlässig lokalisiert. Die Kopplungen der Schätzer des Ausgleichs sind sowohl durch zufällige als auch durch systematische Fehler bedingt. Folglich tritt eine neue, durch systematische Fehler bedingte Klasse geometrischer Körper neben die begrifflich bekannten Konfidenz-Ellipsoide, die zufälligen Fehlern Ausdruck verleihen. Der Verfasser bezeichnet die neuen Körper als Sekuritäts-Polytope.
Symmetries of coincidence site lattices of cubic lattices
Authors: Zeiner Peter
Published: September 2005

We consider the symmetries of coincidence site lattices of 3-dimensional cubic lattices. This includes the discussion of the symmetry groups and the Bravais classes of the CSLs. We derive various criteria and necessary conditions for symmetry operations of CSLs. They are used to obtain a complete list of the symmetry groups and the Bravais classes of those CSLs that are generated by a rotation through the angle π.
About the degree of hydration in potassiumtrisoxalatochromate hydrate
Authors: Hu Chunhua , Heger Gernot , Kalf Irmgard , Englert Ullrich
Published: September 2005

Data obtained from single crystal X-ray and neutron diffraction experiments have been combined with results from thermogravimetry in order to derive an improved structure model for potassium tris(oxalato)chromate hydrate. The degree of hydration for this compound has been reinvestigated: Earlier work assumed a trihydrate stoichiometry and had to accept an unusually short K···O distance of 2.3 Å. Our neutron data reveal the position of the hydrogen atoms in the water molecules; they prove that abnormally short separations between a cation and atoms of a water molecule can only occur between sites of mutually exclusive occupancy and hence remain without chemical relevance. Closest K···O distances in our revised hydration model amount to 2.6 Å, in good agreement with expectation. Both diffraction experiments and thermogravimetric data agree with the stoichiometry K3[Cr(ox)3] · 2.7 H2O for the title compound.
To crystal chemistry of compounds of MHgYX (M = Cu, Ag, Y = S, Se, X = Cl, Br, I)
Authors: Borisov Stanislav V. , Magarill Svetlana A. , Pervukhina Natalie V.
Published: September 2005

In the crystal structures MHgYX (M = Cu, Ag, Y = S, Se, X = Cl, Br, I) and also in CuHg2S2I and Ag2HgSI2 the packing of anions X and Y varies from the hexagonal closest packing (CuHgSI, CuHg2S2I, and α-AgHgSI) to a cubic space-centered packing (Ag2HgSI2, CuHgSBr (295 K), β-AgHgSI, and CuHgSBr (358 K). The packing regularity for large (I–) and smaller (S2–) anions is ensured because Hg2+ has linear coordination S—Hg—S (S—S ≈ 4.5 Å), which is comparable with I—I contacts in a joint close packing. S2–(Se2–) are surrounded in a tetrahedral manner and form stable groups (Hg,M)4
Y where the most strong chemical bonds Hg—Y, M—Y, Hg—Hg (∼3.5 Å), Hg—M are concentrated. The chains, layers, and frameworks of (Hg,M)4
Y tetrahedra form a “skeleton” and, thus, determine the structure form and the sizes of elementary cells.
The crystal structures of solvent-free alkali-metal squarates from powder diffraction data
Authors: Dinnebier Robert E. , Nuss Hanne , Jansen Martin
Published: September 2005

The crystal structures of solvent-free lithium, sodium, rubidium, and cesium squarates have been determined from high resolution synchrotron and X-ray laboratory powder patterns. Crystallographic data at room temperature of Li2C4O4: a = 7.1073(3) Å, b = 9.5627(4) Å, c = 3.2973(1) Å, β = 101.11(1)°, V = 219.91(1) Å3, monoclinic, C2/m, Z = 2, Na2C4O4: a = 3.4925(1) Å, b = 6.8152(1) Å, c = 10.3525(2) Å, β = 91.56(1)° V = 246.32(1) Å3, monoclinic, P21/c, Z = 2; Rb2C4O4: a = 10.7908(5) Å, b = 6.8494(3) Å, c = 4.4521(2) Å, β = 92.39(0), V = 328.77(4) Å3, monoclinic, C2/m, Z = 2; Cs2C4O4: a = 11.1768(3) Å, b = 7.0453(2) Å, c = 4.7424(1) Å, β = 92.89(1)°; V = 372.97(4) Å3, monoclinic, C2/m, Z = 2. The packing features of lithium squarate can be deduced from the AlB2 structure type, while sodium, rubidium, and cesium squarate are related to the CdI2 type. The relation between the two types of crystal structures of the squarate dianion is discussed.
PDF from X-ray powder diffraction for nanometer-scale atomic structure analysis of quasicrystalline alloys
Authors: Brühne Stefan , Uhrig Eckhard , Luther Klaus-Dieter , Assmus Wolf , Brunelli Michela , Masadeh Ahmad S. , Billinge Simon J. L.
Published: September 2005

For three icosahedral alloys in the Mg—Zn-RE(RE = Ho, Y) systems, the atomic pair distribution functions (PDFs) have been obtained from sealed X-ray tube (in-house) and synchrotron (ESRF and APS) powder diffraction experiments. The PDFs are at least qualitatively comparable and are suitable for least squares r ≈ 2 nm local structure refinements. A recent local model for si-Ho—Mg—Zn from in-house data can be confirmed using the synchrotron data. Acquisition and the quality of the data from the different sources are discussed. The better resolved synchrotron data open perspectives for larger scale and thus more detailed models.
Synthesis and crystal structure of a homotrinuclear Ni(II) complex
Authors: Durmus Sefa , Ates B. Meltem , Atakol Orhan , Ercan Filiz
Published: September 2005

A tetradentate ONNO type Schiff base was synthesized from salicyaldehyde and 1,4-diaminobutane. Thermogravimetric analysis, elemental analysis and X-ray diffraction results showed this Schiff base to give a trinuclear complex with Ni(II) ions in presence of acetate ions. The complex crystallizes in the triclinic P-1 space group with a = 9.7510(2), b = 10.6854(2), c = 12.4781(4) Å, α = 112.101(3), β = 100.621(4) and γ = 91.733(3)°. Similar to those found in the literature the terminal Ni(II) ions are coordinated to the Schiff base and have a N2O4 coordination sphere. The central Ni(II) ion has a O6 coordination sphere formed by the phenolic oxygens and the acetate bridges. The conformation of the chelate ring formed between the Ni(II) ions and the iminic nitrogens were examined.
Two new mononuclear Ni(II) complexes with reduced ONNO type Schiff base
Authors: Durmus Sefa , Tatar Leyla , Arıcı Cengiz , Dinçer Nazlı , Atakol Orhan , Svoboda Ingrid , Fuess Hartmut
Published: September 2005

N,N′-bis(salicylidene)-1,3-propanediamine (LH2) and N,N′-bis(salicylidene)-2,2′-dimethyl-1,3-propanediamine (DMLH2) were reduced to phenolic amines by using NaBH4. Mononuclear complexes were obtained with Ni (II) in a N3O6 coordination sphere with these amines and N3– ions, in DMF media. It was established with the XRD studies that the coordination spheres were distorted octahedral and the complex obtained with LH2 formed dimeric structures via phenolic OH bonds. The other complex was seen to have monomeric structure. The complexes were characterized by X-ray diffraction, elemental analysis, termogravimetry, IR spectroscopy and simple magnetic susceptibility (Gouy method). In addition, cyclic voltammetric studies have been performed.
The cubic limiting complexes of lattice complexes with trigonal characteristic symmetry
Authors: Koch Elke , Sowa Heidrun
Published: September 2005

Point configurations with cubic inherent symmetry may be generated within certain trigonal space groups. The corresponding limiting-complex relationships were studied. They are caused by a specialization of the axial ratio c/a and require also special coordinate parameters in most cases.

The limiting complexes were derived with the aid of group-subgroup relationships. The material was checked making use of the occurrence of cubic sphere packings within trigonal space groups. The results are presented in a table referring to all lattice complexes with rhombohedral characteristic space groups (two invariant, five univariant, four bivariant, four trivariant) and to one univariant, one bivariant and one trivariant lattice complex with trigonal characteristic space groups.
The Relationship between Economic Hardship and Crime: The Case of Israel and the Palestinians
Authors: Herzog Sergio
Published: October 2005

Numerous theories of crime posit a positive relation between economic hardship and crime, among them rational choice, strain, anomie, social control, and even neo-Marxist models. The present study focuses on the unique framework provided by the large integrated labor force of Palestinian workers employed in Israel over the past few decades. The study was based on time-series analysis of a restricted time period characterized by severe economic hardship among Palestinians due to loss of employment in Israel and increases of crime rates in Israel. A significant positive relationship between economic hardship among Palestinians and property and general crime in Israel was not found; however, a significant positive relationship was obtained in the specific case of motor vehicle theft. The implications of the findings are discussed.
The Trajectory of the United States in the World-System: A Quantitative Reflection
Authors: Chase-Dunn Christopher , Jorgenson Andrew K. , Reifer Thomas E. , Lio Shoon
Published: October 2005

Using improved estimates of world and country GDPs, population, and GDP per capita published by Angus Maddison (2001), we report findings of a quantitative study of the trajectory of the United States in world historical perspective. We compare the U.S. economic hegemony of the twentieth century with the seventeenth-century Dutch hegemony and the British hegemony of the nineteenth century. We also track the trajectories of challengers and discuss the future of hegemonic rivalry and global governance. Our findings support the existence of a sequence of hegemonic rises and declines. Despite a recent plateau in the decline of U.S. economic hegemony, we contend that the United States will continue to decline.
Availability of Clupeid Prey to Primary Piscivores in Smith Mountain Lake, Virginia
Authors: Cyterski Michael J. , Ney John J.
Published: September 2005

Prey supply to predators is limited by the morphology, behavior, and spatial distributions of both predator and prey. To be eaten, prey must co‐occur spatially and temporally with the predator (distribution), the predator must recognize the prey as potential food and successfully capture it (behavior), and the predator must have a mouth large enough to ingest its target (morphology). We quantified the cumulative effect of these three factors on clupeid prey availability to both largemouth bass Micropterus salmoides and striped bass Morone saxatilis in Smith Mountain Lake, Virginia. As expected, morphological constraints were more severe for small predators. Alewives Alosa pseudoharengus were morphologically more available than gizzard shad Dorosoma cepedianum. Incongruent spatial distributions, the result of lake stratification, prevented striped bass from feeding on gizzard shad during summer and limited largemouth bass consumption of alewives. For unknown behavioral reasons, largemouth bass and striped bass consumed only clupeids between 40 and 160 mm total length. For largemouth bass, the available supply of alewives was equivalent to demand and that of gizzard shad exceeded consumption by 53%. For striped bass, the available supply of gizzard shad surpassed consumption by 26% and that of alewives was 4% greater than consumption. Annual consumption by all clupeid predators, including largemouth bass and smallmouth bass Micropterus dolomieu, striped bass, walleye Sander vitreus, flathead catfish Pylodictis olivaris, channel catfish Ictalurus punctatus, white catfish Ameiurus catus, and crappies Pomoxis spp., was 94% of the total available clupeid supply. Our analysis indicates that increased predation on the clupeid forage base of Smith Mountain Lake would lead to decreased prey production and produce prey shortages for piscivores that are dependent on this food resource.
Seasonal Movement Patterns and Habitat Preferences of Age‐0 Lake Sturgeon in the Lower Peshtigo River, Wisconsin
Authors: Benson Angela C. , Sutton Trent M. , Elliott Robert F. , Meronek Thomas G.
Published: September 2005

Efforts to restore lake sturgeonAcipenser fulvescensto former population levels in the Great Lakes will benefit from a thorough understanding of the species' early life history. The rehabilitation of this species will be aided by identifying nursery habitats in riverine environments through characterizing the habitat use and movements of age‐0 fish. The objectives of this study were to determine the habitat preferences and movement patterns of age‐0 lake sturgeon in the lower Peshtigo River, Wisconsin, a tributary of Lake Michigan. Fish were captured from June through October 2002 and 2003 by means of wading, snorkeling, haul‐seine, and backpack electrofishing surveys, and radio transmitters were attached to individuals larger than 74 g. For each capture and relocation site, habitat features were evaluated by measuring water depth, velocity, and temperature and by characterizing substrate type and macroinvertebrate assemblage. Age‐0 lake sturgeon were collected and relocated at water depths less than 2 m over sand substrates and at current velocities less than 0.60 m/s. Capture and relocation sites were dominated by dipteran larvae, and the median macroinvertebrate density was lower at these sites than in the remainder of the study area. Macroinvertebrate diversity index values were also lower at capture sites than in the overall study area. Daily movements of age‐0 lake sturgeon showed that fish exhibited greater activity after dark, whereas seasonal movement patterns were related to changes in water temperature, particularly during fall months as fish moved from the river to Green Bay. These results suggest that shallow, riverine areas with sand substrates, low current velocity, and a predominance of dipteran larvae should be protected as important nursery habitats in Great Lakes tributaries that support spawning populations of lake sturgeon.
Dissolution of whey protein concentrate gels in alkali
Authors: Mercadé‐Prieto Ruben , Chen Xiao Dong
Published: September 2005

The dissolution of whey protein concentrate (WPC) gels has been studied in detail, and the different mechanisms involved have been quantitatively analyzed. The NaOH diffusivity in gels has been determined at different pH at 22°C. Dissolution experiments of gels under several conditions have been performed and compared. Both heat‐induced gels (HIG) and caustic‐induced gels (CIG) have been studied as models to heat‐exchanger fouling deposits. It is proposed that the constant dissolution rate observed at low pH is controlled by the reactions that break down the gel structure, particularly the β‐elimination of intermolecular disulfide bonds. Alkali dissolution of CIG is reduced with increasing the gelation pH, as more crosslinks are present in the gel. It is proposed that a similar mechanism of crosslink formation may explain the low dissolution rates observed in HIG at dissolution pH above 13.1. NaOH diffusion is observed to limit the dissolution process at high temperatures and pH close to 13. © 2005 American Institute of Chemical Engineers AIChE J, 2006
Global multiproduct production–Distribution planning with duty drawbacks
Authors: Oh Hong‐Choon , Karimi I. A.
Published: September 2005

Duty drawback refers to a full or partial refund of paid import duties when an imported merchandise is destroyed, exported, or consumed as a raw material to produce an export. Despite their extensive international trading operations, many manufacturers fail to save costs by claiming duty drawbacks. In the United States alone, estimates of unclaimed duty drawbacks range from US$1.5–10 billion per annum. In light of this hefty sum of unclaimed duty drawbacks, it is astounding that only one existing production–distribution model in the literature has attempted to include duty drawback. This article is the first to address this neglect of duty drawback in supply chain research by industry practitioners and academicians. To this end, it introduces the key concepts of duty drawback and explains its importance in the new economic era. Second, it presents a linear programming model incorporating three key regulatory factors—corporate taxes, import duties, and duty drawbacks—for solving a production–distribution problem in the chemical industry. Finally, through illustrative examples, it demonstrates the importance of incorporating duty drawback and other regulatory factors in production–distribution planning models. © 2005 American Institute of Chemical Engineers AIChE J, 2006
Interstitial deletion of chromosome 12q: Genotype–phenotype correlation of two patients utilizing array comparative genomic hybridization
Authors: Klein Ophir D. , Cotter Philip D. , Schmidt Ann M. , Bick David P. , Tidyman William E. , Albertson Donna G. , Pinkel Daniel , Rauen Katherine A.
Published: September 2005

Interstitial deletions of chromosome 12q are rare, with only 11 reported cases in the literature. We recently described two cases with cytogenetically identical interstitial deletions of the long arm of chromosome 12. Here, we report on a third patient, a 26‐month‐old male with a cytogenetically‐identical interstitial deletion: 46,XY,del(12)(q21.2q22). Phenotypic features of this male proband included craniofacial and ectodermal anomalies, genitourinary anomalies, minor cardiac abnormalities, mild ventriculomegaly on brain MRI, hyperopia, and developmental delay. To further define the extent of the chromosomal aberration, microarray‐based comparative genomic hybridization (array CGH) analysis was performed and the array data was compared to one of our previously reported cases. Although cytogenetic analysis of the two patients was concordant, molecular analysis by array CGH revealed that the patients had discordant distal breakpoints. The determination of molecular breakpoints and phenotypic analyses in these two patients, in conjunction with previously reported cases, leads us to propose a 12q deletion phenotype and a possible genetic locus for hyperkeratosis pilaris/ulerythema ophryogenes. © 2005 Wiley‐Liss, Inc.
Reduction of the efficacy of methotrexate by the use of folic acid: Post hoc analysis from two randomized controlled studies
Authors: Khanna Dinesh , Park Grace S. , Paulus Harold E. , Simpson Karen M. , Elashoff David , Cohen Stanley B. , Emery Paul , Dorrier Catharine , Furst Daniel E.
Published: September 2005

Objective

To examine the effect of folic acid on the efficacy of methotrexate (MTX) treatment in rheumatoid arthritis (RA) at 12 months in 2 phase III randomized controlled trials (RCTs) of leflunomide in which MTX was used as a comparator.

Methods

Analyses were restricted to patients randomized to receive MTX who had rheumatoid factor data. The US study recruited 482 patients with active RA; 179 received at least 1 dose of MTX, and all were mandated to receive 1 mg of oral folic acid once or twice daily. The multinational European study recruited 999 patients with active RA; 489 received at least 1 dose of MTX, and oral folic acid was not required, although 50 received folate after developing an adverse event. Because of similar entry criteria for both studies, the data for patients with available primary outcome data at week 52 were pooled (n = 668), and the patients were grouped by folic acid use (n = 225) and nonuse (n = 443). To account for the significant between‐study differences in the MTX groups, baseline covariates were adjusted using propensity scores so that folic acid users could be matched with nonusers. This allowed for a comparison of differences in American College of Rheumatology (ACR) 20% improvement criteria at week 52.

Results

At study entry, non–folic acid users had a significantly lower mean body weight, shorter mean RA duration, and higher mean disease activity (measured by joint counts, patient's and physician's global assessments, and acute‐phase reactant levels). The mean MTX dosage at week 52 was similar in the 2 RCTs. Using propensity score matching techniques, the proportion of patients achieving an ACR 20% response at week 52 averaged 17% higher in the non–folic acid group than in the folic acid group (range 15–21%). Similarly, the proportion of patients achieving ACR 50% and ACR 70% responses averaged 14% (range 12–16%) and 12% (range 9–14%) higher, respectively, in the non–folic acid group. Adverse events were reported in 93% of US study patients and 94% of the multinational study patients. Elevated liver transaminase levels (above the upper limit of normal) were reported in 29% of the US study patients (majority receiving folic acid) and 62% of the multinational study patients (majority not receiving folic acid).

Conclusion

After using propensity scores to adjust for differences in the baseline characteristics of folic acid users and non–folic acid users, 9–21% fewer MTX‐treated RA patients taking folic acid had ACR 20%, 50%, or 70% improvement at 52 weeks compared with those who did not receive folic acid in the 2 phase III RA clinical trials. As a post hoc analysis, the results of this data analysis should be considered “hypothesis generating” and an impetus for future studies regarding the effects of folic acid on the efficacy of MTX in RA.