bluuebunny/crossref_metadata_2025 huggingface dataset:
Endothelial dysfunction and systemic inflammation in persons with echolucent carotid plaques
Authors: Mathiesen Ellisiv , Amiral Jean , Vissac Anne , Hansen John-Bjarne , Notø Ann-Trude
Published: June 2006

Echolucent carotid plaques are associated with high risk for future ischemic cerebrovascular events independent of the degree of stenosis. Elevated levels of markers of systemic inflammation and endothelial dysfunction are predictors for future myocardial infarction and stroke.The present study was undertaken to investigate the relations between plaque morphology, endothelial dysfunction assessed by tissue-plasminogen activator antigen (t-PA ag) and von Willebrand factor (vWF), and systemic inflammation in persons with carotid stenosis.We conducteda crosssectional study including 133 persons with carotid stenosis and 138 controls without stenosis recruited from the populationbased Tromsø Study. High-resolution B-mode and colour Doppler/pulsed-wave Doppler ultrasonography of both carotid arteries was performed, and plaque morphology in terms of echogenicity was assessed. Persons with carotid stenosis had significantly higher plasma t-PA and vWF concentrations than controls. There was a significant inverse relationship between t-PA ag and plaque echogenicity (p=0.034).The increased plasma t-PA ag in persons with carotid stenosis was not associated with increased plasminogen activator inhibitor-I (PAI-1).Persons with echolucent carotid plaques had higher degree of systemic inflammation, and plasma t-PA and vWF concentration increased significantly across quartiles of WBC, fibrinogen, and hs-CRP. Our findings may suggest that plasma t-PA may be superior to vWF asa marker for endothelial dysfunction due to its ability to discriminate between various plaque echogenicity, and that the predictive role of t-PA ag in cardiovascular disease is independent of inhibited fibrinolysis.
Identification of factor inhibitors by diagnostic haemostasis laboratories
Authors: Bonar Roslyn , Duncan Elizabeth , Earl Gail , Low Joyce , Aboud Margaret , Just Sarah , Sioufi John , Street Alison , Marsden Katherine , Favaloro Emmanuel ,   on behalf of the RCPA QAP in Haematology Haemostasis Committe
Published: June 2006

We have assessed the proficiency of diagnostic haemostasis facilities to correctly identify coagulation factor abnormalities and inhibitors. Forty-two laboratories participating in the external Quality Assurance Program (QAP) conducted by the RCPA agreed to participate and were each sent a set of eight sample (each 3x1ml) for evaluation. They were asked to blind test these samples for the presence or absence of inhibitors, and wher identified, to perform further analysis (including specific inhibitor analysis). In order to make the exercise more challenging, in addition to true factor inhibitors, samples were provided that reflected potential pre-analytical variables that might arise and complicate inhibitor detection or lead to false inhibitor identification. In brief, the sample set comprised a true high level factor (F)V inhibitor, a true moderate level FVIII inhibitor (but sample was defibrinogenated),a true lupus anticoagulant (LA),a normal (but slightly aged) plasma sample, a normal serum sample, a normal EDTA sample, an oral anticoagulant/vitamin K deficiency sample, and a gross heparin (∼10U/ml) contaminated sample. Sixty-three percent of participants correctly identified the true FV inhibitor as such, although the reported range varied greatly [10 to >250 Bethesda units (BU/ml)] and 46% correctly identi fied the true FVIII inhibitor, despite the complication of the sample presentation, although the reported range also varied (7 to 64 BU/ml). Some laboratories either failed to identify the inhibitor present, or misidentified the inhibitor type. The LA, the oral anticoagulant/vitamin K deficiency, the normal serum sample, and the normal (aged) sample were also correctly identified by most laboratories, as was the absence of specific factor inhibitors in these samples. However, a small subset of laboratories incorrectly identified the presence of specific factor inhibitors in some of these samples. The heparin sample was also correctly identified by most (68%) laboratories. In contrast, the normal EDTA sample was misidentified as a FV and/or FVIII inhibitor by most (68%) laboratories, and only one laboratory correctly identified this as an EDTA sample. Thus, we conclude that although laboratories are able, in most cases, to identify the presence of true factor inhibitors, there is a large variation in identified inhibitor levels and there are also some significant errors in identification (i.e. false negatives and misidentifications). In addition, there is a significant false positive error rate where some laboratories will identify the presence of specific factor inhibitors where no such inhibitor exists (i.e. false positives).
Antithrombotic properties of Ixolaris, a potent inhibitor of the extrinsic pathway of the coagulation cascade
Authors: Nazareth Rômulo , Tomaz Luana , Ortiz-Costa Susana , Atella Geórgia , Ribeiro José , Francischetti Ivo , Monteiro Robson
Published: June 2006

Ixolaris is a two-Kunitz tick salivary gland protein identified in Ixodes scapularis that presents extensive sequence homology t TFPI.It binds to FXa or FX as scaffolds and inhibits tissue factor/ FVIIa complex (extrinsic Xnase). Differently from TFPI, ixolaris does not bind to the active site cleft of FXa. Instead, comple formation is mediated by the FXa heparin-binding exosite,which may also results in decreased FXa activity into the prothrombi nase complex.In this report,we show that recombinant 125I-ixo laris interacts with rat and human FX in plasma and prolongs the prothrombin time (PT) and activated partial thromboplastin time (aPTT) in vitro.We have also investigated the effects of ixo laris in vivo, using a venous thrombosis model. Subcutaneous (s.c.) or intravenous (i.v.) administration of ixolaris in rats caused a dose-dependent reduction in thrombus formation, with complete inhibition attained at 20 µg/kg and 10 µg/kg, re spectively. Antithrombotic effects were observed 3 h after s.c. administration of ixolaris and lasted for 24 h thereafter. Ex vivo experiments showed that ixolaris (up to 100 µg/kg) did not affect the aPTT,while the PT was increased by ∼0.4-fold at the hig hest ixolaris concentration. Remarkably, effective antithrom botic doses of ixolaris (20 µg/kg) was not associated with bleed ing which was significant only at higher doses of the anticoagulant (40 µg/kg).Our experiments demonstrate that ixolaris is an effective and possibly safe antithrombotic agen in viv .
Thermal Expansion of Aluminum–Fly Ash Cenosphere Composites Synthesized by Pressure Infiltration Technique
Authors: Rohatgi P. K. , Gupta N. , Alaraj Simon
Published: June 2006

The coefficients of thermal expansion (CTEs) of commercially available pure aluminum and aluminum alloy composites containing hollow fly ash particles (cenospheres) of average size 125 mm are measured using a dilatometer. Three types of composites are made using the pressure infiltration technique at applied pressures and infiltration times of 35 kPa for 3 min, 35 kPa for 7 min, and 62 kPa for 7 min. The volume fractions of the fly ash cenospheres in the composites are around 65%. The CTE of the composites is measured to be in the range of 13.1×10-6-11×10-6/°C, which is lower than that of pure aluminum (25.3×10-6/°C). The infiltration processing conditions are found to influence the CTE of the composites. A higher applied pressure and a longer infiltration time lead to a lower CTE. The theoretical value of the CTE of fly ash cenospheres is estimated to be 6.1×10-6/°C.
Regional Identities and the Limits of Democratic Centralism in the GDR
Authors: Palmowski Jan
Published: June 2006

Through the administrative reform of 1952, which replaced the five federal states with fourteen districts, the GDR became by far the most centralized state in German history. There has been a remarkable scholarly consensus that following on from this reform state and party were successful in overcoming regional and local identifications. Historians and social scientists discerned a revival of regional identifications from the late 1970s, and explained this as a popular response to the re-evaluation of regional traditions by state and party. This article demonstrates, by contrast, that regional traditions were alive and well throughout the existence of the GDR. Whereas it is true that during the 1960s and the 1970s the state tried to popularize its districts, state and party were always constrained by other, conflicting concerns. Most importantly, the popular demand for leisure and entertainment could be met most easily (and most cheaply) with folklore. Moreover, accentuating regional diversity through local tradition became crucial in a small country in which travel opportunities abroad were extremely restricted. The evolution of local identifications in the GDR points to the limits of a dictatorship. The SED was severely constrained by the divergent interests of different cultural actors, and by the party's acceptance that it needed to respond to popular cultural desires. This article also shows how, over the 40 years of the GDR's existence, distinctive local identities developed and evolved without ever being closely linked to socialism or the state. This insight is indispensable for understanding how the GDR dissolved in 1990, and the persistence of regional specificities and identifications that long outlasted the GDR.
Last Chance to Avoid War: Sadat's Peace Initiative of February 1973 and its Failure
Authors: Bar-Joseph Uri
Published: June 2006

Most studies of the attempts to reach a political solution to the Egyptian–Israeli dispute between the wars of 1967 and 1973 focus predominantly on the Jarring mission (1968–71), the Rogers plan (1969–70) and Sadat's plan for a partial agreement in the Canal sector (early 1971). However, as this article shows on the basis of new archival documents, the most important diplomatic initiative during this period was Sadat's proposal for a comprehensive settlement of the Egyptian–Israeli dispute, which was secretly submitted to Kissinger in February 1973. Despite the fact that it met most of Israel's requirements regarding peace, Sadat's proposal was rejected by Golda Meir, who refused to return the territories occupied in 1967. Meir's stand did not change even when, in April 1973, Israel's leadership concluded that the only alternative to the diplomatic process was war — which would break out soon. By making this decision, Golda Meir and her colleagues opted for war rather than peace and turned the October 1973 Yom Kippur War into ‘a war of choice’.
On the Stability of the Passive Dynamics of Quadrupedal Running with a Bounding Gait
Authors: Poulakakis Ioannis , Papadopoulos Evangelos , Buehler Martin
Published: June 2006

This paper examines the passive dynamics of quadrupedal bounding. First, an unexpected difference between local and global behavior of the forward speed versus touchdown angle in the self-stabilized Spring Loaded Inverted Pendulum (SLIP) model is exposed and discussed. Next, the stability properties of a simplified sagittal plane model of our Scout II quadrupedal robot are investigated. Despite its simplicity, this model captures the targeted steady state behavior of Scout II without dependence on the fine details of the robot structure. Two variations of the bounding gait, which are observed experimentally in Scout II, are considered. Surprisingly, numerical return map studies reveal that passive generation of a large variety of cyclic bounding motion is possible. Most strikingly, local stability analysis shows that the dynamics of the open loop passive system alone can confer stability to the motion! These results can be used in developing a general control methodology for legged robots, resulting from the synthesis of feedforward and feedback models that take advantage of the mechanical system, and might explain the success of simple, open loop bounding controllers on our experimental robot.
How Technology Has Influenced the Field of Corporate Communication
Authors: Argenti Paul A.
Published: June 2006

This commentary serves as a sequel to and an update of the author's earlier article “Corporate Communication as a Discipline: Toward a Definition.” In addition to presenting new information about the field of corporate communication, the author discusses the particular effect that technology has had on the field as both a function in business and a discipline within the academy. He focuses specifically on the challenges and opportunities that new technologies have brought to the field and explores possibilities for teaching and research.
Downsize My Polity? The Impact of Size on Party Membership and Member Activism
Authors: Weldon Steven
Published: June 2006

This study examines a long-standing concern in democratic theory: the relationship between polity size and democratic participation. Size is thought to have a direct effect on the individual's proclivity to take part in collective action, as well as indirect effects through increased bureaucratic complexity and group heterogeneity – two factors often related to group size. The study operates at two levels. At the nation-state level, it examines the relationship between size and party membership rates in 27 representative democracies. It then extends the analysis to the party organization level, examining the effect of party size on members' activism in 29 parties across 5 advanced industrial democracies. The results show that increasing size strongly diminishes participation at both levels.
CBC.ca
Authors: O’Neill Brian
Published: June 2006

Canadian Broadcasting Corporation (CBC), like many public broadcasters, has identified the value of branding their services on the world wide web as a crucial element in the strategy to bring radio into the digital era. Their approach highlights a number of strategically important issues facing broadcasters in the current environment. The internet, in Canadian terms, is an unregulated space and a not particularly Canadian space. Just as in the terrestrial environment, broadcasters like CBC have to operate in an environment dominated by United States-based interests. The regulatory solutions that Canada has previously pursued in order to preserve cultural sovereignty may be either inadequate or inappropriate for the new media environment. Evidence shows that, despite producing distinctive and innovative radio content informed by public service values, the new media marketplace in which internet and other forms of digital radio operate is one in which even significant brands such as CBC will find success difficult.
The 5-HT2C receptor and antipsychoticinduced weight gain – mechanisms and genetics
Authors: Reynolds Gavin P. , Hill Matthew J. , Kirk Shona L.
Published: June 2006

The mechanisms underlying weight gain resulting from antipsychotic drugs are not fully understood, although antagonism of the 5-HT2C receptor is likely to contribute. Animal studies indicate that the drugs most likely to cause weight gain, clozapine and olanzapine, have direct effects on the NPY-containing neurons of the hypothalamus; these neurons mediate the effects of the circulating anorexigenic hormone leptin on the control of food intake.

The substantial differences between individuals in the extent of antipsychotic-induced weight gain suggest that genetic factors may be important. We have been studying pharmacogenetic correlates and find that a common 5-HT2C receptor promoter region polymorphisms demonstrates strong associations with weight gain in two first episode psychotic samples. In both series, we have found further association of antipsychotic drug-induced weight gain with a common and functional polymorphism of the gene for leptin. Along with initial BMI, these two pharmacogenetic factors account for almost 30% of the variance in drug-induced weight gain. Interestingly, the 5-HT2C polymorphism appears to determine levels of circulating leptin, providing a potential mechanism underlying the genetic association of the 5-HT2C receptor with weight gain. We have undertaken functional studies of haplotypes of the 5-HT2C promoter region and find the allele associated with protection from weight gain results in reduced promoter activity.

These findings demonstrate the value of pharmacogenetics in determining liability to a major side effect of antipsychotic treatment, and indicate both the molecular and physiological mechanisms underlying this side effect.
Relevance of assessing drug concentration exposure in pharmacogenetic and imaging studies
Authors: Lotrich Francis E. , Bies Robert R. , Smith Gwenn S. , Pollock Bruce G.
Published: June 2006

Pharmacodynamic differences are difficult to interpret without drug concentration data. In particular, variability in drug exposure may confound the interpretation of pharmacogenetic, therapeutic outcome, and neuroimaging studies. Inter-individual variability in concentrations can be quite high due to variable adherence and pharmacokinetics. For example, clearance may be influenced by genetics, drug interactions, age and illness. We review findings that acute responses to selective serotonin reuptake inhibitors can have a concentration–response relationship using positron emission tomography and neuroendocrine measures. We also present preliminary evidence that the concentration–response relationship for paroxetine is influenced by genotypic differences at the serotonin transporter promoter.

In large clinical studies, the accurate assessment of drug exposure can be challenging, with several techniques used to assess exposure. Population pharmacokinetics (Pop PK) is a method that is ideally suited for analysing concentration data from large trials because both patient-specific and population parameters can be determined with only a small number of plasma samples per patient. As opposed to relying on prescribed doses or a single trough level, the ability to determine more accurately exposure with Pop PK reduces the heterogeneity introduced by exposure variability. Pop PK hierarchic Bayesian approaches have been effective for characterizing anticonvulsants, antibiotics, antineoplastics and antiarrhythmics. We have recently successfully incorporated these pop PK analyses into routine assessments of elderly patients in clinical trials of selective serotonin reuptake inhibitors (SSRIs) and second generation antipsychotics. For the design and interpretation of neuroimaging, pharmacogenetic, and behavioural studies, the assessment of drug concentration exposure is therefore feasible and has potentially important ramifications.
Psychopathy
Authors: Vien Anh , Beech Anthony R.
Published: June 2006

The purpose of this article is to link empirical literature to the theoretical background of the concept of psychopathy and the impact that this has had on the development of treatment and intervention procedures for psychopathic offenders. This article begins with a discussion of the different theories of psychopathy, which leads into considerations of different developmental pathways of psychopathy in the individual. The discussion will then lead on to the psychometrics and measurement tools used to assess psychopathy in the individual. The measurement section will primarily be focused on Hare's Psychopathy Checklist–Revised (PCL-R), as this is the most frequently used and validated measure of psychopathy. The relationship between psychopathy and different types of crime is also discussed.The final section of the article considers the treatment and interventions that are available to psychopathic offenders and the implications this has for future research.
The contractile vacuole in Ca2+-regulation in Dictyostelium: its essential function for cAMP-induced Ca2+-influx
Authors: Malchow Dieter , Lusche Daniel F , Schlatterer Christina , De Lozanne Arturo , Müller-Taubenberger Annette
Published: June 2006

Background

cAMP-induced Ca2+-influx in Dictyostelium is controlled by at least two non-mitochondrial Ca2+-stores: acidic stores and the endoplasmic reticulum (ER). The acidic stores may comprise the contractile vacuole network (CV), the endosomal compartment and acidocalcisomes. Here the role of CV in respect to function as a potential Ca2+-store was investigated.

Results

Dajumin-GFP labeled contractile vacuoles were purified 7-fold by anti-GFP-antibodies in a magnetic field. The purified CV were shown for the first time to accumulate and release Ca2+. Release of Ca2+ was elicited by arachidonic acid or the calmodulin antagonist W7, the latter due to inhibition of the pump. The characteristics of Ca2+-transport and Ca2+-release of CV were compared to similarly purified vesicles of the ER labeled by calnexin-GFP. Since the CV proved to be a highly efficient Ca2+-compartment we wanted to know whether or not it takes part in cAMP-induced Ca2+-influx. We made use of the LvsA--mutant expected to display reduced Ca2+-transport due to loss of calmodulin. We found a severe reduction of cAMP-induced Ca2+-influx into whole cells.

Conclusion

The contractile vacuoles in Dictyostelium represent a highly efficient acidic Ca2+-store that is required for cAMP-induced Ca2+-influx.
In vitro antimicrobial activity of natural toxins and animal venoms tested against Burkholderia pseudomallei
Authors: Perumal Samy R , Pachiappan A , Gopalakrishnakone P , Thwin Maung M , Hian Yap E , Chow Vincent TK , Bow Ho , Weng Joseph T
Published: June 2006

Background

Burkholderia pseudomallei are the causative agent of melioidosis. Increasing resistance of the disease to antibiotics is a severe problem in treatment regime and has led to intensification of the search for new drugs. Antimicrobial peptides are the most ubiquitous in nature as part of the innate immune system and host defense mechanism.

Methods

Here, we investigated a group of venoms (snakes, scorpions and honey bee venoms) for antimicrobial properties against two strains of Gram-negative bacteria Burkholderia pseudomallei by using disc-diffusion assay for in vitro susceptibility testing. The antibacterial activities of the venoms were compared with that of the isolated L-amino acid oxidase (LAAO) and phospholipase A2 (PLA2s) enzymes. MICs were determined using broth dilution method. Bacterial growth was assessed by measurement of optical density at the lowest dilutions (MIC 0.25 mg/ml). The cell viability was measured using tetrazolium salts (XTT) based cytotoxic assay.

Results

The studied venoms showed high antimicrobial activity. The venoms of C. adamanteus, Daboia russelli russelli, A. halys, P. australis, B. candidus and P. guttata were equally as effective as Chloramphenicol and Ceftazidime (30 μg/disc). Among those tested, phospholipase A2 enzymes (crotoxin B and daboiatoxin) showed the most potent antibacterial activity against Gram-negative (TES) bacteria. Naturally occurring venom peptides and phospholipase A2 proved to possess highly potent antimicrobial activity against Burkholderia pseudomallei. The XTT-assay results showed that the cell survival decreased with increasing concentrations (0.05–10 mg/mL) of Crotalus adamanteus venom, with no effect on the cell viability evident at 0.5 mg/mL.

Conclusion

This antibacterial profile of snake venoms reported herein will be useful in the search for potential antibacterial agents against drug resistant microorganisms like B. pseudomallei.
High incidence of metastatic disease in primary high grade and large extremity soft tissue sarcomas treated without chemotherapy
Authors: Leidinger Benedikt , Heyse Thomas , Schuck Andreas , Buerger Horst , Mommsen Philipp , Bruening Thomas , Fuchs Susanne , Gosheger Georg
Published: June 2006

Background

The risk of metastasis and the survival in patients with primary extremity soft tissue sarcomas is worse when tumour size is large and the grade of malignancy is high. Such tumours may receive chemotherapy and/or radiation therapy (RTX) for optimising local control. Irradiation can either be applied preoperatively or after tumour resection. The question arises if the kind of RTX in the absence of chemotherapy influences the outcome concerning local control, metastatic disease, survival and complications.

Methods

We retrospectively reviewed the clinical outcome of 233 patients with a primary extremity soft tissue sarcoma treated between 1990 – 2000 with a mean follow-up of 35.8 (4–120) months in our institute. 41 patients had high grade, deep and large tumours (>8 cm), an AJCC stage III (no evidence of metastasis prior to treatment) and were treated with limb salvage surgery and irradiation but stayed without additional chemotherapy. Two groups of patients were compared: the first group received postoperative RTX after tumour resection (n = 33); the second group was treated with preoperative RTX (n = 8). Both groups did not differ concerning clinical parameters. We analysed primary and secondary outcomes.

Results

56% (23/41) of the population developed metastatic disease, 24% (10/41) local recurrence. The risk of metastasis was higher in the group with preoperative irradiation (p = 0.046). The overall (p = 0.0248) and relapse free survival (p = 0.104) were worse in this group. The delay to tumour resection amounted 8 weeks on average in the preoperative group. Local control was not different (p = 0.38) in both study groups. Wound infections and other combined therapy related complications were equally distributed (p = 0.22).

Conclusion

Without chemotherapy there remains a high risk of metastasis in AJCC grade 3 patients. In high risk patients treated without chemotherapy the elapsed time to tumour resection after preoperative radiation might contribute to the development of metastasis. This outcome may support the thesis that a combination of RTX and offensive multimodal treatment protocols is advantageous in such a subset of patients
Effect of pH on trout blood vessels and gill vascular resistance
Authors: Smith Michael P. , Dombkowski Ryan A. , Wincko Jeffrey T. , Olson Kenneth R.
Published: June 2006

pH is recognized as a modulator of vascular smooth muscle (VSM) tone in mammalian vessels, but little is known about its effects on fish VSM. We investigated the effects of extracellular and intracellular pH (pHoand pHi, respectively) on isolated vessels from steelhead and rainbow trout (Oncorhynchus mykiss, Skamania and Kamloops strains,respectively) and of pHo on perfused gills from rainbow trout. In otherwise unstimulated (resting) efferent branchial (EBA) and coeliaco-mesenteric arteries (CMA), anterior cardinal veins (ACV) and perfused gills, increasing pHo from 6.8 to 8.8–9.0 produced a dose-dependent contraction or increase in gill resistance(RGILL) with an estimated half-maximal response of 8.0–8.2. pHo interactions with other contractile stimuli were agonist specific; more force was developed at low pHo in ligand-mediated (arginine vasotocin) contractions, whereas depolarization-mediated (40–80 mmol l–1 KCl)contractions were greatest at high pHo. Increasing pHiby application of 40 mmol l–1 NH4Cl produced sustained contraction in afferent branchial arteries (ABA) suggesting that these vessels could not readily restore pHi. NH4Cl application only transiently contracted EBA and CMA in Hepes buffer, whereas it produced a slight, but prolonged, relaxation of EBA and CMA in Cortland buffer. The buffer effect was due to the presence of Hepes and in this environment EBA and CMA appeared to readily restore pHi. Increasing pHi in KCl-contracted EBA in Hepes produced an additional contraction, whereas ligand-contracted (thromboxane A2 analog,U-46619) EBA relaxed. Reducing pHi (NH4Cl washout)transiently contracted resting EBA and CMA in both Hepes and Cortland buffer. NH4Cl washout produced an additional, transient contraction of both KCl- and U-46619-contracted EBA in Hepes. EBA contractions produced by increased pHi depend primarily on intracellular Ca2+,whereas both intracellular and extracellular Ca2+ contributed to the response to decreased pHi. Three cycles of perfusate acidification (pHo 7.8 to 6.2 and back to 7.8) reproducibly halved,then restored RGILL with no adverse effects, indicating that this was not a pathophysiological response. These studies show that the general effects of pH on VSM are phylogenetically conserved from fish to mammals but even within a species there are vessel-specific differences. Furthermore, as fish are exposed to substantial fluctuations in environmental(and therefore plasma) pH, the obligatory response of fish VSM to these changes may have substantial impact on cardiovascular homeostasis.
Synthesis of and Ferromagnetic Coupling in Poly(phenylenevinylene)s Bearing Built-in t-Butyl Nitroxides
Authors: Nishide Hiroyuki , Kaneko Takashi , Toriu Shuichi , Kuzumaki Yoshihiro , Tsuchida Eishun
Published: June 2006

Poly[[2- or 4-[N-t-butyl-N-(triethylsiloxy- or t-butyldimethylsiloxy)amino]-1,4- or 1,2-phenylene]vinylene] was synthesized by polymerizing 4- or 2-bromo-2- or 4-[N-t-butyl-N-(triethylsiloxy- or t-butyldimethylsiloxy)amino]styrene with a palladium catalyst, respectively. They were deprotected and chemically oxidized to yield poly(1,4- or 1,2-phenylenevinylene)s bearing a 2- or 4-substituted built-in nitroxide radical. The polyradicals were chemically stable, and their spin concentration was increased to 0.8 spin/unit. A SQUID measurement which included the corresponding diradicals and triradicals indicated that a partial, but strong, intramolecular ferromagnetic coupling was established through the conjugated backbone, despite a spin defect in the side radical moiety, for the poly(1,2- phenylenevinylene) bearing 4-substituted built-in nitroxide radical.
Photooxygenation of 1,1-Diarylethylenes via Addition of Oxygen to the 1,4-Dimer Radical Cations, Catalyzed by 10-Methylacridinium Ion
Authors: Fujita Morifumi , Shindo Akira , Ishida Akito , Majima Tetsuro , Takamuku Setsuo , Fukuzumi Shunichi
Published: June 2006

Photooxygenation of 1,1-diarylethylene occurs efficiently using 10-methylacridinium ion as a photocatalyst to yield the 1,2-dioxane and/or the diaryl ketone depending on the substituents on the aryl groups. The reaction mechanism is revealed based on the dependence of the quantum yields on the concentrations of the alkene and oxygen, the fluorescence quenching of 10-methylacridinium ion by the alkene, and the direct detection of reactive intermediates by applying laser flash spectroscopy as well as pulse radiolysis. The photooxygenation proceeds via photoinduced electron transfer from the alkene to the singlet excited state of 10-methylacridinium ion. The alkene radical cation formed by the photoinduced electron transfer reacts with alkene to give the 1,4-dimer radical cation, which then reacts with oxygen to produce the oxygenated 1,6-radical cation. The subsequent one-electron reduction of the 1,6-radical cation results in formation of the 1,6-biradical which cyclizes to yield 1,2-dioxane derivative or fragmentates to yield diaryl ketone. When the 1,6-biradical is reduced by the alkene itself, the alkene radical cation is regenerated to repeat the radical chain process.
Reactivities and Properties of Lanthanide Catalysts Prepared by Thermal Degradation of Liquid Ammonia Solutions of Eu or Yb Metal
Authors: Imamura Hayao , Konishi Tomohiro , Suda Eisaku , Sakata Yoshihisa , Tsuchiya Susumu
Published: June 2006

Studies of X-ray diffraction, Fourier-transform infrared spectra and catalytic properties of lanthanide catalysts (Eu/AC and Yb/AC) prepared by impregnation of active carbon (AC) with liquid ammonia solutions of Eu or Yb metal were carried out for the catalytic hydrogenation of ethene. The lanthanides thus deposited on AC were changed through varied steps (metal, amide, imide or nitride) by thermal treatments and simultaneously the hydrogenation activity varied markedly. Eu/AC and Yb/AC which were subjected to the evacuation treatment around 573 and 773 K, respectively, showed a high activity even at 203 K. The catalytic properties of lanthanide amide (Eu(NH2)2, Yb(NH2)2, and Yb(NH2)3) prepared separately, imide and nitride were investigated for comparison. It was concluded that imide or imide-like species formed during the thermal decomposition processes of europium(II) and ytterbium(II and III) amides to nitride at 503—573 and 423—773 K was active catalysts for Eu/AC and Yb/AC, respectively.
Aqueous Media Effect on Molecular Recognition. II. Temperature Dependence of Chemical Selectivity in Alcohols and Water
Authors: Endo Tadashi , Aono Yoshihiro , Yazawa Takashi , Hayashi Munetoshi , Yokose Yuuichi , Iida Takahiro , Isago Takashi
Published: June 2006

Oxidation of a pair of associating thiols (1 and 2), each having the binding site [–C(=O)NHC(=O)NH–] and the recognition site (R1 or R2), is examined at several temperatures in alcohols (MeOH, EtOH, n-PrOH, and i-PrOH) and water. The selectivity (r), a measure of molecular recognition of 1 by 2 (or of 2 by 1), in the oxidation is defined as the logarithmic ratio of the yield of an unsymmetrical disulfide (4) to twice that of a symmetrical one (3). It is found that the selectivity in the alcohols each decreases markedly with increasing temperature except for one case, whereas that in water increases with increasing temperature. Correlation of the observed selectivity with factors affecting the selectivity (e.g., intermolecular association, physicochemical properties of solvents, and hydrophobic interaction) is discussed.
Catalysis by Organic Solids. Stereoselective Intramolecular Ene Reaction of Citronellal Promoted by Microporous Molecular Crystals Having an Extensive Hydrogen-Bonded Network
Authors: Sawaki Tomoya , Endo Ken , Kobayashi Kenji , Hayashida Osamu , Aoyama Yasuhiro
Published: June 2006

5,5′-(9,10-Anthracenediyl)diresorcinol (1) (host) and a terpenoid aldehyde citronellal (2, guest) form a 1 : 2 adduct 1·2(2), in which the guest molecules hydrogen-bonded to the host are closely packed in an extended conformation in the microporous crystal structure of the host. When heated in vacuo, the 1 : 2 adduct loses ca. 1 molecule of the guest to give a 1 : 1 adduct 1·2. The guest 2 included in both adducts undergoes a facilitated intra-adduct ene reaction to afford isopulegol as the main product. Such a reaction in the 1 : 1 adduct occurs smoothly and in a highly stereoselective (ca. 98%) manner. The reaction in the 1 : 2 adduct is less stereoselective and exhibits a sigmoidal progression curve having a significant “induction period”. The present ene reaction of citronellal (2) as either a neat liquid or in a cyclohexane solution is catalyzed by host 1 in the solid state. The allosteric cooperativity observed is discussed in view of a big conformational change associated with the present cyclization reaction.
Superstition and Rational Learning
Authors: Fudenberg Drew , Levine David K
Published: June 2006

We argue that some, but not all, superstitions can persist when learning is rational and players are patient, and illustrate our argument with an example inspired by the Code of Hammurabi. The code specified an “appeal by surviving in the river” as a way of deciding whether an accusation was true. According to our theory, a mechanism that uses superstitions two or more steps off the equilibrium path, such as “appeal by surviving in the river,” is more likely to persist than a superstition where the false beliefs are only one step off the equilibrium path.
Zur Rolle der Logik in der Linguistik: Formale Modellbildung und funktionale Sprachtheorie
Authors: Winkler Marco
Published: June 2006

This paper discusses the relationship of logic and linguistics and pleads for logic-based formal model building in linguistic theory. At first, I describe the assignments and the purpose of logic in arts in general and the interrelation between logic and linguistics. Taking into account philosophical conditions and the subject of both, language, I argue for a functional-linguistic point of view. A detailed investigation is devoted to the concept of predicates. Based on logical theory, namely the non-traditional theory of predication and the term-theory developed by A. A. Sinowjew and H. Wessel, a formal approach to modelling linguistic comprehensions of predicates is devised. On this base I carry out a logical reconstruction of some concepts of linguistic theory, like the quantitative and qualitative features of arguments and their thematic roles, and explain their relations to logical predicate-argument-structures. In a further step predicate forming operations are used to describe and to reconstruct diatheses, argument deletion and the influence of mass terms on predication. By this, I want to introduce formal tools for the explanation of such natural-language phenomena and line out how the formal results allow to solve several puzzles.
Pneumatic Impact Ignition of Sebum Oil Film in High-Pressure Oxygen
Authors: Tapia SA , Smith SR , Hshieh F-Y , Stoltzfus JM
Published: June 2006

Whenever oxygen systems are assembled or maintained, a risk of introducing contamination arises. Potential contaminants include oils from a person's hands and body left behind in the form of fingerprints. The oil on the surface of skin is a complex mixture of sebum oil, lipids, sweat, and environmental materials. In high-pressure systems, heat from rapid pressurization is a high-risk ignition mechanism for the sebum contaminant. The rapid pressurization or pneumatic impact ignition of hydrocarbon-based oil contaminant in high-pressure oxygen has been widely studied. This study investigated the rapid pressurization ignition of sebum contaminant in high-pressure oxygen. The pneumatic impact ignition test of sebum contaminant was conducted according to NASA-STD-6001 Test 14. The ends of stainless steel cylindrical rods were coated with synthetic sebum at varying surface concentrations, and impacted with 27.6 MPa oxygen. The results show that there is a threshold level of sebum contaminant for ignition by rapid pressurization. The level of sebum contaminant that can be expected to be deposited by handling oxygen system components, an analysis on sebum oil properties and associated fire hazards, and the threshold levels of sebum contaminant required for rapid pressurization ignition in a high-pressure oxygen system are presented and discussed.
Statistical Analysis of Pathogenicity of Somatic Mutations in Cancer
Authors: Greenman Chris , Wooster Richard , Futreal P Andrew , Stratton Michael R , Easton Douglas F
Published: June 2006

Recent large-scale sequencing studies have revealed that cancer genomes contain variable numbers of somatic point mutations distributed across many genes. These somatic mutations most likely include passenger mutations that are not cancer causing and pathogenic driver mutations in cancer genes. Establishing a significant presence of driver mutations in such data sets is of biological interest. Whereas current techniques from phylogeny are applicable to large data sets composed of singly mutated samples, recently exemplified with a p53 mutation database, methods for smaller data sets containing individual samples with multiple mutations need to be developed. By constructing distinct models of both the mutation process and selection pressure upon the cancer samples, exact statistical tests to examine this problem are devised. Tests to examine the significance of selection toward missense, nonsense, and splice site mutations are derived, along with tests assessing variation in selection between functional domains. Maximum-likelihood methods facilitate parameter estimation, including levels of selection pressure and minimum numbers of pathogenic mutations. These methods are illustrated with 25 breast cancers screened across the coding sequences of 518 kinase genes, revealing 90 base substitutions in 71 genes. Significant selection pressure upon truncating mutations was established. Furthermore, an estimated minimum of 29.8 mutations were pathogenic.
New Alleles of SIR2 Define Cell-Cycle-Specific Silencing Functions
Authors: Matecic Mirela , Martins-Taylor Kristen , Hickman Merrit , Tanny Jason , Moazed Danesh , Holmes Scott G
Published: June 2006

The establishment of transcriptional silencing in yeast requires cell-cycle progression, but the nature of this requirement is unknown. Sir2 is a protein deacetylase that is required for gene silencing in yeast. We have used temperature-sensitive alleles of the SIR2 gene to assess Sir2's contribution to silencing as a function of the cell cycle. When examined in vivo, these conditional alleles fall into two classes: one class exhibits a loss of silencing when raised to the nonpermissive temperature regardless of cell-cycle position, while the second class exhibits a mitosis-specific silencing defect. Alleles of the first class have a primary defect in protein deacetylase activity, while the alleles of the second class are specifically defective in Sir2–Sir4 interactions at nonpermissive temperatures. Using a SIR2 temperature-sensitive allele, we show that silencing can be established at the HML locus during progression through the G2/M–G1 interval. These results suggest that yeast heterochromatin undergoes structural transitions as a function of the cell cycle and support the existence of a critical assembly step for silent chromatin in mitosis.
The RAD6/BRE1 Histone Modification Pathway in Saccharomyces Confers Radiation Resistance Through a RAD51-Dependent Process That Is Independent of RAD18
Authors: Game John C , Williamson Marsha S , Spicakova Tatiana , Brown J Martin
Published: June 2006

We examine ionizing radiation (IR) sensitivity and epistasis relationships of several Saccharomyces mutants affecting post-translational modifications of histones H2B and H3. Mutants bre1Δ, lge1Δ, and rtf1Δ, defective in histone H2B lysine 123 ubiquitination, show IR sensitivity equivalent to that of the dot1Δ mutant that we reported on earlier, consistent with published findings that Dot1p requires H2B K123 ubiquitination to fully methylate histone H3 K79. This implicates progressive K79 methylation rather than mono-methylation in IR resistance. The set2Δ mutant, defective in H3 K36 methylation, shows mild IR sensitivity whereas mutants that abolish H3 K4 methylation resemble wild type. The dot1Δ, bre1Δ, and lge1Δ mutants show epistasis for IR sensitivity. The paf1Δ mutant, also reportedly defective in H2B K123 ubiquitination, confers no sensitivity. The rad6Δ, rad51null, rad50Δ, and rad9Δ mutations are epistatic to bre1Δ and dot1Δ, but rad18Δ and rad5Δ show additivity with bre1Δ, dot1Δ, and each other. The bre1Δ rad18Δ double mutant resembles rad6Δ in sensitivity; thus the role of Rad6p in ubiquitinating H2B accounts for its extra sensitivity compared to rad18Δ. We conclude that IR resistance conferred by BRE1 and DOT1 is mediated through homologous recombinational repair, not postreplication repair, and confirm findings of a G1 checkpoint role for the RAD6/BRE1/DOT1 pathway.
Implant Treatment in an Urban General Dentistry Residency Program: A 7-year Retrospective Study
Authors: Starr Clifford B. , Maksoud Mohamed A.
Published: June 2006

Survival rates of multiple implant designs placed in various clinical situations average more than 90%. However, little data have been published on the survival rates of implants placed in dental residency programs. This study reports on the outcome of dental implants placed by first-year general dentistry residents in the University of Florida College of Dentistry–Jacksonville Clinic. The patients for this study received both surgical and restorative implant therapy from 1998 to 2005. A total of 263 patients (147 women, 116 men) were treated with dental implants. On average, a patient was 55.5 years old and received 3 implants. A variety of simple and complex restorative procedures were performed. Advanced general dentistry residents in conjunction with supervisory faculty treated all cases. The cumulative implant survival was 96.6%. Follow-up varied from 6 months to 7 years after placement. Cases included implants not yet loaded as well as implants loaded for 6 years or more. The findings of this study compare favorably with published studies and were unexpected in light of the residents' limited clinical experience.
Effect of Practical Diets with Animal or Vegetable Protein Sources and Poultry Oil or Menhaden Fish Oil on Adult Fathead Minnow in Tanks
Authors: Lochmann Rebecca , Kumaran Sathyanand
Published: June 2006

The fathead minnow Pimephales promelas is one of the main species cultured in ponds in the southern United States for bait and is widely used as a toxicological and biomedical model in the laboratory. Diet can have a major impact on performance criteria, both in laboratory and production settings. However, the nutrient requirements of fathead minnow are unknown and cannot be used to formulate optimal diets. To facilitate applied nutrition research for this species, we measured the growth, survival, feed conversion, and response to low dissolved oxygen exhibited by adults that were held in tanks and fed practical diets with animal (menhaden Brevoortia spp. fish meal and poultry by-product meal) or plant (mostly soybean) protein sources and either poultry oil or menhaden fish oil for 12 weeks. Good weight gain (0.6–0.8 g) was obtained either with vegetable or animal protein sources. Poultry oil enhanced growth relative to menhaden fish oil in diets with either vegetable or animal protein sources. Mean survival rates of fish fed the animal and vegetable protein diets were 88% and 96%, respectively, and survival was not affected by lipid source. Survival during the low-oxygen stress test was high (≥90%) across diets, and there were no treatment effects. Vegetable proteins and poultry oil are promising alternatives to more costly feed ingredients in practical diets for fathead minnow.
Set-up effect in long piles in weathered soils
Authors: Shek L. M. P. , Zhang L. M. , Pang H. W.
Published: June 2006

Field tests were conducted to study set-up effects in long driven piles founded in completely decomposed granite (CDG). Two steel H-piles 56 m and 58 m in embedment depth were fully instrumented with vibrating-wire strain gauges and installed. Several restrike dynamic tests were carried out on each test pile from 1 day and up to 95 days after the end of initial driving. Static load testing was later carried out to substantiate the dynamic tests. The test programme is described in detail. Changes with time in pile capacity and in the shaft and toe resistances were studied based on the results of the pile tests. The development of the shaft resistance set-up with depth and time was studied in particular. It was found that setup took place in the shaft resistance and relaxation in the toe resistance. The overall set-up was found to be at the lower bound of the values found with concrete piles. More significant set-up in shaft resistance was observed in the shallower fill and alluvium layers. The dimensionless set-up factor A for shaft resistance in CDG ranged from 0·53 to 1·06, and the set-up factor decreased with depth and with increasing blow count in the standard penetration test.
Dynamic response of laterally loaded piles in clay
Authors: Boominathan A. , Ayothiraman R.
Published: June 2006

The behaviour of single piles under lateral dynamic loading is critical, and has been an important field of research since the 1950s. Many analytical or semi-analytical linear and non-linear models are available to estimate the dynamic lateral stiffness, but it is essential to determine the dynamic characteristics of the soil–pile system through full-scale lateral dynamic pile load tests for important structures and for validation of existing models. This paper presents the results of field lateral dynamic load tests conducted on 33 piles of varying types–driven precast concrete, driven cast-in-situ concrete and bored cast-in-situ concrete–at different petrochemical complexes in India. The results indicate that driven precast concrete piles have stiffnesses that are four to five times higher than those of driven cast in situ piles. The lateral stiffness was also estimated using the computer program PILAY for all piles and compared with the stiffness determined from the field tests. The estimated stiffness shows good agreement with the field values for stiff clay sites, but greatly overestimates the values for soft clay sites.