bluuebunny/crossref_metadata_2025 huggingface dataset:
Systemic and local ibandronate enhance screw fixation
Authors: Skoglund Björn , Holmertz Jonas , Aspenberg Per
Published: February 2004

The trauma involved with inserting implants into bone leads to an activation of the inflammatory response and an activation of osteoclasts. In addition, apoptosis of osteocytes in the surrounding area has been implicated in further activation of osteoclasts. If the balance between resorption and bone formation shortly after implantation favours resorption, an impairment of early fixation might ensue.

Because bisphosphonates inhibit resorption, this study analyses whether they can improve early fixation. Stainless steel screws (M 1.7) were inserted into the tibiae of 76 male Sprague‐Dawley rats. Daily subcutaneous injections of ibandronate (3 μg) or saline were given to 20 rats. The remaining rats received ibandronate or saline directly applied into the drill hole before the screw was inserted. Tibiae were harvested at 14 days. Mechanical tests were performed on 50 tibiae. Systemically treated tibiae were tested for pull‐out strength alone. Locally treated tibiae were tested for either pull‐out or torque resistance. The remaining 18 tibiae were prepared for histology.

Systemic ibandronate increased the pull‐out force at failure by 30% (p = 0.04). Local treatment increased the force at failure by 15% (p = 0.02) and stiffness by 28% (p = 0.01). In the removal torque measurements, local ibandronate increased the torque‐moment at failure by 60% (p = 0.04), and the maximum friction moment by 51% (p = 0.04). Energy for turning the screw 1/4 revolution was increased by 68% (p = 0.02).

These results demonstrate that early remodeling events plays an important role in screw fixation, and that systemic or local bisphosphonate treatment could be an effective pharmacological path to improve early implant fixation. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
IRT-basierter Vergleich zweier Varianten automatisiert erstellter Matrizentestaufgaben
Authors: Arendasy Martin E. , Gittler Georg
Published: February 2004

Zusammenfassung: In der vorliegenden Arbeit wird über 2 Pilotstudien im Vorfeld der Entwicklung eines Itemgenerators zur vollautomatisierten Herstellung von Matrizentestaufgaben berichtet. Besonderes Augenmerk wurde auf den Vergleich zweier theoriegeleitet erstellter Varianten von Items gelegt und ob sich diese als geeignet erweisen, bei automatisierter Itemgenerierung mit erwünscht hoher psychometrischer Qualität (Geltung des Modells von Rasch, 1960/1980 ) erstellt werden zu können. Die durchgeführten Studien weisen aus Sicht der IRT auf prinzipielle Gleichwertigkeit der beiden Itemvarianten bei unterschiedlicher Robustheit der erzielbaren psychometrischen Qualität hin. Dieses Ergebnis wird im Lichte von “affordances” und “constraints” im Hinblick auf Konstruktrepräsentativität der beiden Itemvarianten diskutiert ( Greeno, Moore & Smith, 1993 ). Zusätzlich konnten wertvolle Erkenntnisse für die Erweiterung des generativen Regelwerks zur Einbindung in den Itemgenerator gewonnen werden. Abschließend werden mögliche weitere Entwicklungsrichtungen kurz skizziert.
Die “ARES-Skalen” zur Erfassung der individuellen BIS- und BAS-Sensitivität
Authors: Hartig Johannes , Moosbrugger Helfried
Published: February 2004

Zusammenfassung: Das psychobiologische Modell von J.A. Gray nimmt zwei grundlegende Emotionssysteme als Basis zweier korrespondierender grundlegender Persönlichkeitsdimensionen an: Das Behavioral Inhibition System (BIS) und das Behavioral Approach System (BAS). Zur Erfassung der Dimensionen BIS- und BAS-Sensitivität stellen die BIS/BAS-Skalen von Carver und White (1994) die bisher viel versprechendste Skalenkonstruktion dar, jedoch sind diese hinsichtlich der Skaleneigenschaften noch nicht völlig zufrieden stellend. Aufbauend auf dem Grayschen Modell und unter Rückgriff auf zentrale Überlegungen von Carver und White wurden deutsche Skalen zur Erfassung der Sensitivität der beiden Emotionssysteme (Action Regulating Emotion Systems; ARES) in einer Langfassung (58 Items) und einer Kurzfassung (20 Items) neu konstruiert. Die ARES-Skalen enthalten die Subskalen BIS I “Ängstlichkeit” und BIS II “Frustration” zur Erfassung der individuellen BIS- und die Subskalen BAS I “Antrieb” und BAS II “Freude” zur Erfassung der individuellen BAS-Sensitivität. Die Skalen weisen sehr zufrieden stellende psychometrische Eigenschaften und eine mit Grays Modell übereinstimmende faktorielle Struktur.
Faktorstruktur, Gütekriterien und Konstruktvalidität der deutschen Übersetzung des Aggressionsfragebogens von Buss und Perry
Authors: Herzberg Philipp Yorck
Published: February 2004

Zusammenfassung: Für die deutsche Übersetzung des Aggressionsfragebogens von Buss und Perry (1992) konnte gezeigt werden, dass nach Ausschluss von zwei Items und der Einführung von drei korrelierten Fehlertermen die postulierte vierfaktorielle Struktur des AF-BP mit den Primärfaktoren körperliche Aggression, verbale Aggression, Ärger und Feindseligkeit, die einen Faktor höherer Ordnung konstituieren, psychometrischen Standards genügt. Die internen Konsistenzen und zeitliche Stabilität der Skalen ist mit Ausnahme der verbalen Aggression als gut einzustufen. Erste Befunde zur konvergenten und diskrimanten Validität stützen die Konstruktvalidität des BP-AF, allerdings zeigt die Skala verbale Aggression nicht das erwartete Zusammenhangsmuster.
A Social Identidy Model of Media Usage and Effects
Authors: Reid Scott A. , Giles Howard , Abrams Jessica R.
Published: February 2004

Abstract. We propose a social identity model of media usage and effects. This model explains how the media might cultivate power arrangements (i.e., promote social stasis) on the one hand, and contribute to social change on the other. We argue that current media theories are ill-equipped to meet both of these explanatory challenges. The model integrates (1) social identity processes with (2) Herman and Chomsky’s (1988) propaganda model, and (3) Abrams, Eveland, and Giles’s (2003) work on media images and group vitality. Social stasis is produced when the social environment is stable, and when people with status quo-consistent beliefs (i.e., social mobility and social creativity) engage with the media to confirm their beliefs. Social change occurs when people with socially competitive beliefs engage in actions (e.g., riots, peace marches) that re-inform others as to the instability and illegitimacy (among other things) of the current status and power relations in the world. If these actions are sufficiently persuasive, people’s social beliefs will change and, with them, the social world.
Debattenwahrnehmung und Kandidatenorientierung
Authors: Maier Jürgen , Faas Thorsten
Published: February 2004

Zusammenfassung. Bei der Bundestagswahl 2002 wurden erstmals Fernsehduelle nach US-amerikanischem Vorbild durchgeführt. Mit Hilfe von experimentell erhobenen Daten geht der vorliegende Beitrag folgenden Fragen nach: Wie wird die Debattenleistung von Schröder und Stoiber bewertet? Welche Faktoren sind für die Wahrnehmung der Debattenleistung verantwortlich? Welche Rolle spielt die wahrgenommene Debattenleistung für die Bewertung der beiden Kandidaten, und welche Rolle kommt hier non-verbalen Verhaltensmustern zu? Die Ergebnisse zeigen, dass die Auftritte beider Kontrahenten vorwiegend positiv beurteilt wurden. Die Wahrnehmung der Debattenleistung hängt dabei vor allem von bereits vor den Duellen existierenden Einstellungen, aber auch von den non-verbalen Signalen ab, die die beiden Kandidaten aussenden. Die perzipierte Debattenleistung wiederum beeinflusst die Einstellung zu den Kandidaten - und hier vor allem die Bewertung des politischen Gegners - erheblich.
Protein kinase A regulates ATP hydrolysis and dimerization by a CFTR (cystic fibrosis transmembrane conductance regulator) domain
Authors: HOWELL L. Daniel , BORCHARDT Roy , KOLE Jolanta , KAZ Andrew M. , RANDAK Christoph , COHN Jonathan A.
Published: February 2004

Gating of the CFTR Cl− channel is associated with ATP hydrolysis at the nucleotide-binding domains (NBD1, NBD2) and requires PKA (protein kinase A) phosphorylation of the R domain. The manner in which the NBD1, NBD2 and R domains of CFTR (cystic fibrosis transmembrane conductance regulator) interact to achieve a properly regulated ion channel is largely unknown. In this study we used bacterially expressed recombinant proteins to examine interactions between these soluble domains of CFTR in vitro. PKA phosphorylated a fusion protein containing NBD1 and R (NBD1–R–GST) on CFTR residues Ser-660, Ser-700, Ser-712, Ser-737, Ser-768, Ser-795 and Ser-813. Phosphorylation of these serine residues regulated ATP hydrolysis by NBD1–R–GST by increasing the apparent Km for ATP (from 70 to 250 µM) and the Hill coefficient (from 1 to 1.7) without changing the Vmax. When fusion proteins were photolabelled with 8-azido-[α-32P]ATP, PKA phosphorylation increased the apparent kd for nucleotide binding and it caused binding to become co-operative. PKA phosphorylation also resulted in dimerization of NBD1–R–GST but not of R–GST, a related fusion protein lacking the NBD1 domain. Finally, an MBP (maltose-binding protein) fusion protein containing the NBD2 domain (NBD2–MBP) associated with and regulated the ATPase activity of PKA-phosphorylated NBD1–R–GST. Thus when the R domain in NBD1–R–GST is phosphorylated by PKA, ATP binding and hydrolysis becomes co-operative and NBD dimerization occurs. These findings suggest that during the activation of native CFTR, phosphorylation of the R domain by PKA can control the ability of the NBD1 domain to hydrolyse ATP and to interact with other NBD domains.
alphaII-Spectrin is an in vitro target for caspase-2, and its cleavage is regulated by calmodulin binding
Authors: ROTTER Björn , KROVIARSKI Yolande , NICOLAS Gaël , DHERMY Didier , LECOMTE Marie-Christine
Published: February 2004

The spectrin–actin scaffold underlying the lipid bilayer is considered to participate in cell-shape stabilization and in the organization of specialized membrane subdomains. These structures are dynamic and likely to undergo frequent remodelling during changes in cell shape. Proteolysis of spectrin, which occurs during apoptosis, leads to destabilization of the scaffold. It is also one of the major processes involved in membrane remodelling. Spectrins, the main components of the membrane skeleton, are the targets for two important protease systems: m- and µ-calpains (Ca2+-activated proteases) and caspase-3 (activated during apoptosis). In this paper, we show that caspase-2 also targets spectrin in vitro, and we characterize Ca2+/calmodulin-dependent regulation of spectrin cleavage by caspases. Yeast two-hybrid screening reveals that the large isoform (1/L) of procaspase-2 specifically binds to αII-spectrin, while the short isoform does not. Like caspase-3, caspase-2 cleaves αII-spectrin in vitro at residue Asp-1185. This study emphasizes a role of executioner caspase for caspase-2. We also demonstrated that the executioner caspase-7 but not caspase-6 cleaves spectrin at residue Asp-1185 in vitro. This spectrin cleavage by caspases 2, 3 and 7 is inhibited by the Ca2+-dependent binding of calmodulin to spectrin. In contrast, calmodulin binding enhances spectrin cleavage by calpain at residue Tyr-1176. These results indicate that αII-spectrin cleavage is highly influenced by Ca2+ homoeostasis and calmodulin, which therefore represent potential regulators of the stability and the plasticity of the spectrin-based skeleton.
Regulation of protein synthesis by eIF4E phosphorylation in adult cardiocytes: the consequence of secondary structure in the 5′-untranslated region of mRNA
Authors: TUXWORTH William J. , SAGHIR Atif N. , SPRUILL Laura S. , MENICK Donald R. , McDERMOTT Paul J.
Published: February 2004

In adult cardiocytes, eIF4E (eukaryotic initiation factor 4E) activity and protein synthesis are increased concomitantly in response to stimuli that induce hypertrophic growth. We tested the hypothesis that increases in eIF4E activity selectively improve the translational efficiency of mRNAs that have an excessive amount of secondary structure in the 5´-UTR (5´-untranslated region). The activity of eIF4E was modified in primary cultures of adult cardiocytes using adenoviral gene transfer to increase either the amount of eIF4E or the extent of endogenous eIF4E phosphorylation. Subsequently, the effects of eIF4E on translational efficiency were assayed following adenoviral-mediated expression of luciferase reporter mRNAs that were either ‘stronger’ (less structure in the 5´-UTR) or ‘weaker’ (more structure in the 5´-UTR) with respect to translational efficiency. The insertion of G+C-rich repeats into the 5´-UTR doubled the predicted amount of secondary structure and was sufficient to reduce translational efficiency of the reporter mRNA by 48±13%. Translational efficiency of the weaker reporter mRNA was not significantly improved by overexpression of wild-type eIF4E when compared with the stronger reporter mRNA. In contrast, overexpression of the eIF4E kinase Mnk1 [MAP (mitogen-activated protein) kinase signal-integrating kinase 1] was sufficient to increase the translational efficiency of either reporter mRNA, independent of the amount of secondary structure in their respective 5´-UTRs. The increases in translational efficiency produced by Mnk1 occurred in association with corresponding decreases in mRNA levels. These findings indicate that the positive effect of eIF4E phosphorylation on translational efficiency in adult cardiocytes is coupled with the stability of mRNA.
Paenibacillus sp. TS12 glucosylceramidase: kinetic studies of a novel sub-family of family 3 glycosidases and identification of the catalytic residues
Authors: PAAL Krisztina , ITO Makoto , WITHERS Stephen G.
Published: February 2004

GCase (glucosylceramidase) from Paenibacillus sp. TS12, a family 3 glycosidase, hydrolyses the β-glycosidic linkage of glucosylceramide with retention of anomeric configuration via a two-step, double-displacement mechanism. Two carboxyl residues are essential for catalysis, one functioning as a nucleophile and the other as a general acid/base catalyst. p-Nitrophenyl β-d-glucopyranoside [Km=0.27±0.02 mM and kcat/Km=(2.1±0.2)×106 M−1·s−1] and 2,4-dinitrophenyl β-d-glucopyranoside [Km=0.16±0.02 mM and kcat/Km=(2.9±0.4)×106 M−1·s−1] were used for continuous assay of the enzyme. The dependence of kcat (and kcat/Km) on pH revealed a dependence on a group of pKa≤7.8 in the enzyme–substrate complex which must be protonated for catalysis. Incubation of GCase with 2,4-dinitrophenyl 2-deoxy-2-fluoro-β-d-glucopyranoside caused time-dependent inactivation (Ki=2.4±0.7 mM and ki=0.59±0.05 min−1) due to the accumulation of a trapped glycosyl–enzyme intermediate. Electrospray ionization MS analysis of the peptic digest of this complex showed that the enzyme was covalently labelled by the reagent at Asp-223, consistent with its role as nucleophile. A mutant modified at this residue (D223G) showed substantially reduced activity compared with the wild type (>104), but this activity could be partially restored by addition of formate as an external nucleophile. Kinetic analysis of the mutant E411A indicated that Glu-411 serves as the general acid/base catalytic residue since this mutant was pH-independent and since considerable GCase activity was restored upon addition of azide to E411A, along with formation of a glycosyl azide product.
Phosphorylation of 20S proteasome alpha subunit C8 (alpha7) stabilizes the 26S proteasome and plays a role in the regulation of proteasome complexes by gamma-interferon
Authors: BOSE Suchira , STRATFORD Fiona L. L. , BROADFOOT Kerry I. , MASON Grant G. F. , RIVETT A. Jennifer
Published: February 2004

In animal cells there are several regulatory complexes which interact with 20S proteasomes and give rise to functionally distinct proteasome complexes. γ-Interferon upregulates three immuno beta catalytic subunits of the 20S proteasome and the PA28 regulator, and decreases the level of 26S proteasomes. It also decreases the level of phosphorylation of two proteasome alpha subunits, C8 (α7) and C9 (α3). In the present study we have investigated the role of phosphorylation of C8 by protein kinase CK2 in the formation and stability of 26S proteasomes. An epitope-tagged C8 subunit expressed in mammalian cells was efficiently incorporated into both 20S proteasomes and 26S proteasomes. Investigation of mutants of C8 at the two known CK2 phosphorylation sites demonstrated that these are the two phosphorylation sites of C8 in animal cells. Although phosphorylation of C8 was not absolutely essential for the formation of 26S proteasomes, it did have a substantial effect on their stability. Also, when cells were treated with γ-interferon, there was a marked decrease in phosphorylation of C8, a decrease in the level of 26S proteasomes, and an increase in immunoproteasomes and PA28 complexes. These results suggest that the down-regulation of 26S proteasomes after γ-interferon treatment results from the destabilization that occurs after dephosphorylation of the C8 subunit.
Bax-induced cytochrome c release from mitochondria depends on alpha-helices-5 and -6
Authors: HEIMLICH Gerd , McKINNON Alastair D. , BERNARDO Katussevani , BRDICZKA Dieter , REED John C. , KAIN Renate , KRÖNKE Martin , JÜRGENSMEIER Juliane M.
Published: February 2004

The pro-apoptotic protein Bax plays a key role in the mitochondrial signalling pathway. Upon induction of apoptosis, Bax undergoes a conformational change and translocates to mitochondrial membranes, where it inserts and mediates the release of cytochrome c from the intermembrane space into the cytosol. However, the domains of Bax that are essential for the induction of cytochrome c release are still elusive. Therefore various Bax deletion mutants were generated and expressed in Escherichia coli. The proteins were then purified in order to delineate the function of the transmembrane domain, the BH3 (Bcl-2 homology 3) domain and the putative pore-forming α-helices-5 and -6. These proteins were used to analyse the mechanism of Bax-induced cytochrome c release from mitochondria. None of the Bax proteins caused cytochrome c release merely through physical perturbation of the mitochondrial outer membrane. The α-helices-5 and -6 of Bax were shown to mediate the insertion of the protein into mitochondrial membranes and to be essential for the cytochrome c-releasing activity of Bax. In contrast, neither the transmembrane domain nor a functional BH3 domain is required for the Bax-mediated release of cytochrome c from mitochondria.
The heptapeptide LSARLAF mediates platelet activation through phospholipase Cgamma2 independently of glycoprotein IIb-IIIa
Authors: PEARCE Andrew C. , WONEROW Peter , MARSHALL Stuart J. , FRAMPTON Jon , GARTNER T. Kent , WATSON Steve P.
Published: February 2004

The seven-amino-acid peptide LSARLAF has been reported to activate platelets via the integrin GPIIb-IIIa (glycoprotein IIb-IIIa). Activation by LSARLAF is reinforced by release of ADP and thromboxanes, but the initiating event in the signalling cascade is not known. In the present study, we demonstrate that LSARLAF stimulates Src kinase-dependent tyrosine phosphorylation of many of the proteins in the GPIIb-IIIa cascade, including the tyrosine kinase Syk, the adapter SLP-76 (SH2-containing leucocyte phosphoprotein of 76 kDa) and PLCγ2 (phospholipase Cγ2). A critical role for PLCγ2 in signalling by LSARLAF was demonstrated by abolition of aggregation in PLCγ2−/− murine platelets to low concentrations of the peptide, although a partial recovery was seen with higher concentrations. In sharp contrast with the GPIIb-IIIa-regulated signalling cascade, aggregation was inhibited in murine platelets deficient in the adapter LAT (linker for activation of T-cells) and the Fc receptor γ-chain. Aggregation was also partially inhibited by the cholesterol-lowering reagent, β-methyl-cyclodextrin, at concentrations that disrupt membrane rafts, but do not interfere with signalling by GPIIb-IIIa. Furthermore, LSARLAF also stimulated tyrosine phosphorylation in GPIIb-deficient murine platelets, confirming that the integrin is not critical for activation of intracellular signalling pathways. LSARLAF also stimulated Ca2+ elevation in RBL-2H3 cells, which lack the platelet glycoproteins GPIIb, GPVI and GPIb. These results demonstrate that LSARLAF activates platelets through a PLCγ2-dependent pathway that lies downstream of Src kinases and which is partially dependent on the Fc receptor γ-chain, LAT and lipid rafts. The mechanism of cell activation by LSARLAF remains to be established, although the present results indicate that more than one surface glycoprotein may mediate this response.
Acylation of SC4 dodecapeptide increases bactericidal potency against Gram-positive bacteria, including drug-resistant strains
Authors: LOCKWOOD Nathan A. , HASEMAN Judith R. , TIRRELL Matthew V. , MAYO Kevin H.
Published: February 2004

We have conjugated dodecyl and octadecyl fatty acids to the N-terminus of SC4, a potently bactericidal, helix-forming peptide 12-mer (KLFKRHLKWKII), and examined the bactericidal activities of the resultant SC4 ‘peptide-amphiphile’ molecules. SC4 peptide-amphiphiles showed up to a 30-fold increase in bactericidal activity against Gram-positive strains (Staphylococcus aureus, Streptococcus pyogenes and Bacillus anthracis), including S. aureus strains resistant to conventional antibiotics, but little or no increase in bactericidal activity against Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). Fatty acid conjugation improved endotoxin (lipopolysaccharide) neutralization by 3- to 6-fold. Although acylation somewhat increased lysis of human erythrocytes, it did not increase lysis of endothelial cells, and the haemolytic effects occurred at concentrations 10- to 100-fold higher than those required for bacterial cell lysis. For insight into the mechanism of action of SC4 peptide-amphiphiles, CD, NMR and fluorescence spectroscopy studies were performed in micelle and liposome models of eukaryotic and bacterial cell membranes. CD indicated that SC4 peptide-amphiphiles had the strongest helical tendencies in liposomes mimicking bacterial membranes, and strong membrane integration of the SC4 peptide-amphiphiles was observed using tryptophan fluorescence spectroscopy under these conditions; results that correlated with the increased bactericidal activities of SC4 peptide-amphiphiles. NMR structural analysis in micelles demonstrated that the two-thirds of the peptide closest to the fatty acid tail exhibited a helical conformation, with the positively-charged side of the amphipathic helix interacting more with the model membrane surface. These results indicate that conjugation of a fatty acid chain to the SC4 peptide enhances membrane interactions, stabilizes helical structure in the membrane-bound state and increases bactericidal potency.
Alteration of the bioenergetic phenotype of mitochondria is a hallmark of breast, gastric, lung and oesophageal cancer
Authors: ISIDORO Antonio , MARTÍNEZ Marta , FERNÁNDEZ Pedro L. , ORTEGA Álvaro D. , SANTAMARÍA Gema , CHAMORRO Margarita , REED John C. , CUEZVA José M.
Published: February 2004

Recent findings indicate that the expression of the β-catalytic subunit of the mitochondrial H+-ATP synthase (β-F1-ATPase) is depressed in liver, kidney and colon carcinomas, providing further a bioenergetic signature of cancer that is associated with patient survival. In the present study, we performed an analysis of mitochondrial and glycolytic protein markers in breast, gastric and prostate adenocarcinomas, and in squamous oesophageal and lung carcinomas. The expression of mitochondrial and glycolytic markers varied significantly in these carcinomas, when compared with paired normal tissues, with the exception of prostate cancer. Overall, the relative expression of β-F1-ATPase was significantly reduced in breast and gastric adenocarcinomas, as well as in squamous oesophageal and lung carcinomas, strongly suggesting that alteration of the bioenergetic function of mitochondria is a hallmark of these types of cancer.
Glucocorticoids regulate mRNA levels for subunits of the 19 S regulatory complex of the 26 S proteasome in fast-twitch skeletal muscles
Authors: COMBARET Lydie , TAILLANDIER Daniel , DARDEVET Dominique , BÉCHET Daniel , RALLIÈRE Cécile , CLAUSTRE Agnès , GRIZARD Jean , ATTAIX Didier
Published: February 2004

Circulating levels of glucocorticoids are increased in many traumatic and muscle-wasting conditions that include insulin-dependent diabetes, acidosis, infection, and starvation. On the basis of indirect findings, it appeared that these catabolic hormones are required to stimulate Ub (ubiquitin)–proteasome-dependent proteolysis in skeletal muscles in such conditions. The present studies were performed to provide conclusive evidence for an activation of Ub-proteasome-dependent proteolysis after glucocorticoid treatment. In atrophying fast-twitch muscles from rats treated with dexamethasone for 6 days, compared with pair-fed controls, we found (i) increased MG132-inhibitable proteasome-dependent proteolysis, (ii) an enhanced rate of substrate ubiquitination, (iii) increased chymotrypsin-like proteasomal activity of the proteasome, and (iv) a co-ordinate increase in the mRNA expression of several ATPase (S4, S6, S7 and S8) and non-ATPase (S1, S5a and S14) subunits of the 19 S regulatory complex, which regulates the peptidase and the proteolytic activities of the 26 S proteasome. These studies provide conclusive evidence that glucocorticoids activate Ub-proteasome-dependent proteolysis and the first in vivo evidence for a hormonal regulation of the expression of subunits of the 19 S complex. The results suggest that adaptations in gene expression of regulatory subunits of the 19 S complex by glucocorticoids are crucial in the regulation of the 26 S muscle proteasome.
Space allocation in Melanophila knoteki knoteki (Reitt.) var. hellenica (Obenberger) (Col., Buprestidae) in the attack of Greek fir [Abies cephalonica Loud. var. graeca (Fraas) Liu]: a pattern to process approach
Authors: Petrakis P. V.
Published: February 2004

The phloeo‐cambiophagous buprestid Melanophila knoteki knoteki (Reitt.) var. hellenica (Obenberger.) is not a primary factor of fir decline problem although the beetle substantially contributes to Greek fir Abies cephalonica Loud. var. graeca (Fraas) Liu mortality. By using mapping depiction of the exit holes of the insect on a set of fir trees located on a line transect in a randomized point‐centred quarter scheme and employing pattern analysis techniques we were able to reveal various scales of the infestation pattern. Four scales were recognized, two of them corresponding to the pattern of microsite selection on the bark of a fir tree. While the dispersed exit holes exhibited a statistically significant random dispersion on the bark, within each aggregation the pattern was uniform. The area of compartments created by Dirichlet partition approximated very well the sizes of the actual larval galleries. The Dirichlet tessellation of the bark space and the analysis of the parameter of the resulting partitions showed the predominance of the hexagonal conformation of the larval spaces when space was limited. When some exit holes were positioned close together it was found that they were directed away from each other so the resulting galleries were well separated. Several hypotheses are presented as to the mechanisms underpinning the observed patterns. The allocation of space is in accordance with the widely accepted ‘central place theory’ of W. Christaller, a general theory of pattern generated in the geographical dispersion of human settlements. The revealed pattern was also in accordance with the predictions of the theory of ‘central place foraging’ of R. H. MacArthur and the theory of ‘resource concentration hypothesis’ of R. Root.
Absence of non‐target effects of two Bacillus thuringiensis coleopteran active δ‐endotoxins on the bulb mite, Rhizoglypus robini (Claparède) (Acari, Acaridae)
Authors: Carter M. E. , Villani M. G. , Allee L. L. , Losey J. E.
Published: February 2004

Transgenic crops with plant‐incorporated protectants are often more specific than synthetic insecticides and have the potential to reduce impacts on non‐target organisms. In this study we assessed the impact of Cry3Aa and Cry3Bb1 coleopteran‐active δ‐endotoxins on the bulb mite, Rhizoglypus robini. The effect of Cry3Aa prototoxin in solutions of the biopesticide Novodor® on mite survival was assessed in laboratory studies. Survival of R. robini exposed to Cry3Aa in a short‐term contact and ingestion experiment was not affected, although R. robini was significantly affected by the insecticide Fipronil® used as a positive control. Similarly, R. robini exposed in a longer duration feeding trial to the Cry3Aa toxin in artificial diet were also not significantly affected. When Cry3Aa was tested on the positive control insect, Leptinotarsa decemlineata, reduced weight of larvae and increased mortality was recorded. The effect of Cry3Bb1 toxin in transgenic corn tissues on R. robini food choice was assessed in a laboratory study. In no‐choice tests a greater proportion of R. robini were found on garlic roots than on Cry3Bb1 transgenic corn and a near‐isogenic non‐transgenic corn. In a choice test, more R. robini was recovered on garlic roots than on either corn variety, and on Cry3Bb1 corn than on non‐transgenic corn. In large field plots using specific mite traps across the growing season, R. robini mite populations were not significantly different between Cry3Bb1 corn and non‐transgenic corn alone or non‐transgenic corn treated with different combinations of two insecticides. Our results, combined with results from other studies, suggest that transgenic plants expressing the Cry3Aa or Cry3Bb1 Bacillus thuringiensis toxins are likely to have negligible impact on R. robini mite populations.
Effects of metaldehyde and methiocarb on feeding preferences and survival of a slug predator (Pterostichus melanarius (F.): Carabidae, Pterostichini)
Authors: Langan A. M. , Taylor A. , Wheater C. P.
Published: February 2004

The potential for reducing slug populations in crops through predation by generalist carabid beetles is well documented. However, few studies have considered interactions between biological and chemical control agents of slugs. Laboratory assays supported previous findings that the consumption of metaldehyde by slugs (Deroceras reticulatum) leads to increased duration of feeding bouts by carabid beetles (such as Pterostichini) on sub‐lethally affected individuals. However, a similar effect was not found for Pterostichus melanarius exposed to slugs fed on the other widely applied pelleted molluscicide formulation (methiocarb). Examination of beetle survival after consumption of slugs containing molluscicides demonstrated the strong biocidal properties of methiocarb, whereas metaldehyde consumption (ingested through slug predation) did not differ from control slugs killed by freezing. Beetle avoidance of slugs containing a more toxic molluscicide compound and the interaction between slug mucus production and beetle attack rates are discussed.
Apple and peach fruit volatiles and the apple constituent butyl hexanoate attract female oriental fruit moth, Cydia molesta, in the laboratory
Authors: Natale D. , Mattiacci L. , Pasqualini E. , Dorn S.
Published: February 2004

Volatiles emitted from immature and mature peach and apple fruits were all attractive to mated female oriental fruit moth, Cydia molesta (Busck), in a dual choice arena. Females did not discriminate between odours emitted by these two major host plants. The same natural blends were behaviourally ineffective for virgin females. A major component of apple fruit volatiles, butyl hexanoate, also attracted female C. molesta. Mated females were attracted to two medium dosages, while virgin females responded positively to the lowest of the five dosages tested. The time course of the captures of the moths shows a diurnal activity cycle known from the field. The possible implications of a semiochemical which attracts females are discussed in the context of previous findings that gravid females may immigrate from peaches into apple orchards particularly in the later phase of the season.
Effects of host on functional response of offspring in two populations of Trissolcus grandis on the sunn pest
Authors: Allahyari H. , Fard P. A. , Nozari J.
Published: February 2004

Trissolcus grandis Thompson is the most important egg parasitoid of Eurygaster integriceps Put. in Iran. It can be reared on some alternative hosts such as eggs of Podisus maculiventris (Say). In this study, the functional response of female wasps that emerged from the factitious host, P. maculiventris, has been compared with that of females that emerged from the primary host, E. integriceps. In both wasp groups, at 23 ± 1°C, 70 ± 10% relative humidity and 15.00 : 9.00 hours (L : D) photoperiod, a type III functional response was observed. Parameters of Holling's disk equation for both populations were estimated and compared with an equation with indicator variable. Estimated handling time for females that emerged from Eurygaster and Podisus eggs are 0.62 and 0.77 h and parameter b, which describes the change in attack rate with host density in a type III functional response, was 0.004 and 0.005, respectively. The results indicated that the functional responses of the two populations differed in handling time. Longer handling time in wasps that emerged from factitious host showed that the wasps have lower quality in comparison with the wasps that emerged from primary host. This may be the first evidence of the effect of host on functional response of offspring and a promising result for use of functional response in quality testing.
Catches of vine bud moth Theresimima ampellophaga (Lep., Zygaenidae: Procridinae) males in pheromone traps: effect of the purity and age of baits, design, colour and height of the traps, and daily sexual activity of males
Authors: Subchev M. , Toshova T. , Tóth M. , Voigt E. , Mikulás J. , Francke W.
Published: February 2004

Pure (2R)‐butyl (7Z)‐tetradecenoate, as well as racemic 2‐butyl (7Z)‐tetradecenoate, in a dose of 100 μg (calculated for the active (2R)‐enantiomer) applied onto serum bottle caps of grey rubber, were an effective pheromone bait for Theresimima ampellophaga (Bayle‐Barelle, 1808) (Lepidoptera: Zygaenidae: Procridinae). This bait remained active for longer than one full flight of the pest in the regions with one generation per year. Colourless transparent as well as red and yellow sticky traps were the cheapest and most simple design for trapping T. ampellophaga, while green and blue traps performed worse. Among the traps tested, VARL (CSALOMON®) funnel traps had the highest capture ability for the pest. Traps had to be mounted at least 1.0–2.0 m above ground level. T. ampellophaga males flew to a source of sex pheromone all day long with a main peak between 07.00 and 09.00 hours and a much smaller one between 19.00 and 21.00 hours.
Interference between male‐targeted and female‐targeted lures of the Mediterranean fruit fly Ceratitis capitata (Dipt., Tephritidae) in Italy
Authors: Tóth M. , Nobili P. , Tabilio R. , Ujváry I.
Published: February 2004

The efficacy of male‐targeted and female‐targeted baits was compared when lures were presented together or singly in traps for capturing the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). For male‐targeted baits, either trimedlure or ceralure presented singly attracted large numbers of flies, supporting data from many previous reports. The present results are the first published data on the attractiveness of ceralure to a European population of C. capitata. The quaternary female bait consisting of ammonium carbonate, putrescine, trimethylamine and acetic acid was a potent attractant for female flies (and also showed some activity for males). Replacing acetic acid with ammonium acetate in the quaternary female bait did not influence activity. Traps with female‐targeted and male‐targeted baits together always showed a tendency of catching fewer flies than traps with only one type of bait. The decrease was significant in females, regardless of whether ceralure or trimedlure was the male‐targeted bait. In males, the tendency was the same for traps with trimedlure or ceralure alone, catching higher numbers than those with both male and female baits. Our present results suggest that both types of baits mutually decrease the numbers of the non‐target sex in the trap. In conclusion, it is advisable to use both male‐ and female‐targeted baits in separate and distant traps and not jointly in the same trap, lest the efficacy of detection or monitoring trials be compromised.
Slow manifold for a bimolecular association mechanism
Authors: Fraser Simon J.
Published: February 2004

Finding the slow manifold for two-variable ordinary differential equation (ODE) models of chemical reactions with a single equilibrium is generally simple. In such planar ODEs the slow manifold is the unique trajectory corresponding to the slow relaxation of the system as it moves towards the equilibrium point. One method of finding the slow manifold is to use direct iteration of a functional equation; another method is to obtain a series solution of the trajectory differential equation of the system. In some cases these two methods agree order-by-order in the singular perturbation parameter controlling the fast relaxation of the intermediate (complex). However, de la Llave has found a model ODE where the series method always diverges. Bimolecular association is an example of a chemical reaction where the series method for finding the slow manifold diverges but the iterative method converges. In this mechanism a complex is formed which can then undergo unimolecular decay, i.e., A+B⇌ lim k−1k1C→ lim k2P. The kinetics of this reaction are investigated and its properties compared with two other two-step mechanisms where series expansion and iteration methods are equivalent: the Michaelis–Menten mechanism for enzyme kinetics, and the Lindemann–Christiansen mechanism of unimolecular decay in gas kinetics.
“Exact” surface free energies of iron surfaces using a modified embedded atom method potential and λ integration
Authors: Grochola Gregory , Russo Salvy P. , Yarovsky Irene , Snook Ian K.
Published: February 2004

Previously a new universal λ-integration path and associated methodology was developed for the calculation of “exact” surface and interfacial free energies of solids. Such a method is in principle applicable to any intermolecular potential function, including those based on ab initio methods, but in previous work the method was only tested using a relatively simple embedded atom method iron potential. In this present work we apply the new methodology to the more sophisticated and more accurate modified embedded atom method (MEAM) iron potential, where application of other free- energy methods would be extremely difficult due to the complex many-body nature of the potential. We demonstrate that the new technique simplifies the process of obtaining “exact” surface free energies by calculating the complete set of these properties for the low index surface faces of bcc and fcc solid iron structures. By combining these data with further calculations of liquid surface tensions we obtain the first complete set of exact surface free energies for the solid and liquid phases of a realistic MEAM model system. We compare these predictions to various experimental and theoretical results.
Effect of exchangeable cation on the swelling property of 2:1 dioctahedral smectite—A periodic first principle study
Authors: Chatterjee Abhijit , Ebina Takeo , Onodera Yoshio , Mizukami Fujio
Published: February 2004

We used both localized and periodic calculations on a series of monovalent (Li+,Na+,K+,Rb+,Cs+) and divalent (Mg2+,Ca2+,Sr2+,Ba2+) cations to monitor their effect on the swelling of clays. The activity order obtained for the exchangeable cations among all the monovalent and divalent series studied: Ca2+>Sr2+>Mg2+>Rb+>Ba2+>Na+>Li+>Cs+>K+. We have shown that, in case of dioctahedral smectite, the hydroxyl groups play a major role in their interaction with water and other polar molecules in the presence of an interlayer cation. We studied both type of clays, with a different surface structure and with/without water using a periodic calculation. Interlayer cations and charged 2:1 clay surfaces interact strongly with polar solvents; when it is in an aqueous medium, clay expands and the phenomenon is known as crystalline swelling. The extent of swelling is controlled by a balance between relatively strong swelling forces and electrostatic forces of attraction between the negatively charged phyllosilicate layer and the positively charged interlayer cation. We have calculated the solvation energy at the first hydration shell of an exchangeable cation, but the results do not correspond directly to the experimental d-spacing values. A novel quantitative scale is proposed with the numbers generated by the relative nucleophilicity of the active cation sites in their hydrated state through Fukui functions within the helm of the hard soft acid base principle. The solvation effect thus measured show a perfect match with experiment, which proposes that the reactivity index calculation with a first hydration shell could rationalize the swelling mechanism for exchangeable cations. The conformers after electron donation or acceptance propose the swelling mechanism for monovalent and divalent cations.
Monolayer/bilayer transition in Langmuir films of derivatized gold nanoparticles at the gas/water interface: An x-ray scattering study
Authors: Fukuto Masafumi , Heilmann Ralf K. , Pershan Peter S. , Badia Antonella , Lennox R. Bruce
Published: February 2004

The microscopic structure of Langmuir films of derivatized gold nanoparticles has been studied as a function of area/particle on the water surface. The molecules (AuSHDA) consist of gold particles of mean core diameter D∼22 Å that have been stabilized by attachment of carboxylic acid terminated alkylthiols, HS–(CH2)15–COOH. Compression of the film results in a broad plateau of finite pressure in the surface pressure versus area/particle isotherm that is consistent with a first-order monolayer/bilayer transition. X-ray specular reflectivity (XR) and grazing incidence diffraction show that when first spread at large area/particle, AuSHDA particles aggregate two dimensionally to form hexagonally packed monolayer domains at a nearest-neighbor distance of a=34 Å. The lateral positional correlations associated with the two-dimensional (2D) hexagonal order are of short range and extend over only a few interparticle distances; this appears to be a result of the polydispersity in particle size. Subsequent compression of the film increases the surface coverage by the monolayer but has little effect on the interparticle distance in the close-packed domains. The XR and off-specular diffuse scattering (XOSDS) results near the onset of the monolayer/bilayer coexistence plateau are consistent with complete surface coverage by a laterally homogeneous monolayer of AuSHDA particles. On the high-density side of the plateau, the electron-density profile extracted from XR clearly shows the formation of a bilayer in which the newly formed second layer on top is slightly less dense than the first layer. In contrast to the case of the homogeneous monolayer, the XOSDS intensities observed from the bilayer are higher than the prediction based on the capillary wave model and the assumption of homogeneity, indicating the presence of lateral density inhomogeneities in the bilayer. According to the results of Bragg rod measurements, the 2D hexagonal order in the two layers of the bilayer are only partially correlated.
van der Waals interactions across stratified media
Authors: Podgornik R. , Parsegian V. A.
Published: February 2004

Working at the Lifshitz level, we investigate the van der Waals interactions across a series of layers with a periodic motif. We derive the complete form of the van der Waals interaction as an explicit function of the number of periodic layers. We then compare our result with an approximation based on an anisotropic-continuum representation of the stratified medium. Satisfactory agreement between discrete-layer and continuum models is reached only for thicknesses of ten or more layers.
Ultrafast carrier dynamics in single-walled carbon nanotubes probed by femtosecond spectroscopy
Authors: Ma Ying-Zhong , Stenger Jens , Zimmermann Jörg , Bachilo Sergei M. , Smalley Richard E. , Weisman R. Bruce , Fleming Graham R.
Published: February 2004

Ultrafast carrier dynamics in individual semiconducting single-walled carbon nanotubes was studied by femtosecond transient absorption and fluorescence measurements. After photoexcitation of the second van Hove singularity of a specific tube structure, the relaxation of electrons and holes to the fundamental band edge occurs to within 100 fs. The fluorescence decay from this band is dependent on the excitation density and can be rationalized by exciton annihilation theory. In contrast to fluorescence, the transient absorption has a distinctly different time and intensity dependence for different tube structures, suggesting a branching to emissive and trap states following photoexcitation.
Electron–intramolecular–vibration interactions in positively charged phenanthrene-edge-type hydrocarbons
Authors: Kato Takashi , Yamabe Tokio
Published: February 2004

Electron–phonon interactions in positively charged phenanthrene-edge-type hydrocarbons such as phenanthrene, chrysene, and picene are studied. The C–C stretching modes around 1500 cm−1 and the low-frequency modes around 500 cm−1 strongly couple to the highest occupied molecular orbitals (HOMO) in phenanthrene-edge-type hydrocarbons. The total electron–phonon coupling constants for the monocations (lHOMO) of 0.251, 0.135, and 0.149 eV for phenanthrene, chrysene, and picene, respectively, are estimated to be larger than those of 0.130, 0.107, and 0.094 eV for anthracene, tetracene, and pentacene, respectively. The phase patterns difference between the HOMO localized on carbon atoms which are located at the molecular edge in acene-edge-type hydrocarbons and the delocalized HOMO in phenanthrene-edge-type hydrocarbons is the main reason for the result. Strengths of orbital interactions between two neighboring carbon atoms in the HOMO become weaker with an increase in molecular size because the electron density on each carbon atom in the HOMO becomes smaller with an increase in molecular size in phenanthrene-edge-type hydrocarbons. On the other hand, the frontier orbitals of acene-edge-type hydrocarbons have somewhat nonbonding characters and thus cannot strongly couple to the totally symmetric vibrational modes compared with the frontier orbitals of phenanthrene-edge-type hydrocarbons. This is the reason why the lHOMO value for phenanthrene-edge-type hydrocarbons decreases with an increase in molecular size more significantly than that for acene-edge-type hydrocarbons, and the reason why the lHOMO value for polyphenanthrene with C2v geometry (0.033 eV) is estimated to be similar to that for polyacene (0.036 eV). The reorganization energies between the neutral molecules and the corresponding monocations for phenanthrene-edge-type hydrocarbons with large molecular size are estimated to be larger than those for acene-edge-type hydrocarbons with large molecular size.