Distribution by Scientific Domains
Distribution within Chemistry

Terms modified by Ru

  • ru atom
  • ru catalyst
  • ru complex

  • Selected Abstracts

    Silicon Surface-Bound Redox-Active Conjugated Wires Derived From Mono- and Dinuclear Iron(II) and Ruthenium(II) Oligo(phenyleneethynylene) Complexes,

    ADVANCED MATERIALS, Issue 10 2008
    Nicolas Gauthier
    Electron-rich mononuclear Fe(II) or dinuclear Fe(II)/Ru(II) acetylide complexes are photochemically grafted onto hydrogenated silicon surfaces following a simple and mild one-step procedure. The monolayers of redox-active organometallics that are formed exhibit efficient electrical communication between their bound metallic centers and the silicon surface through interfacial SiC bonds. [source]

    Scintigraphic examination of the cartilages of the foot

    A. NAGY
    Summary Reasons for performing study: Radiographic examination of the cartilages of the foot is well documented; however, there is limited information about their scintigraphic assessment. Objectives: To evaluate the scintigraphic appearance of the cartilages of the foot using subjective and quantitative image analysis and to correlate radiographic and scintigraphic findings. Hypotheses: An ossified cartilage would have similar radiopharmaceutical uptake (RU) to the ipsilateral aspect of the distal phalanx; RU would extend throughout the length of the ossified cartilage; a separate centre of ossification (SCO) would be identified on a scintigraphic image; and fracture or trauma to an ossified cartilage would manifest as increased RU (IRU). Methods: Front feet (n = 223) of horses (n = 186) that had dorsopalmar radiographic views and dorsal scintigraphic images were included in the study. The cartilages of the foot were graded radiographically and scintigraphically. Quantitative evaluation of the scintigraphic images was carried out using region of interest (ROI) analysis. For statistical analysis RU ratios were used. Correlations between a radiographically detected SCO and focal RU and between IRU and radiographic abnormalities were assessed. Results: There was a good correlation and an excellent agreement between radiographic and scintigraphic grades. ROI analysis showed a proximal to distal increase in RU ratios within each cartilage of the foot. A radiographically identified SCO could be detected scintigraphically in 12/17 feet (70.6%). Thirty-eight feet had IRU in the region of a cartilage, 25 of which (65.8%) had corresponding radiographic abnormalities. Fracture of an ossified cartilage was associated with IRU in all horses. Conclusions and potential relevance: Scintigraphy may give information about the potential clinical significance of ossification of the cartilages of the foot and associated lesions, therefore prompting further investigation by use of a uniaxial ipsilateral palmar nerve block and imaging, using either magnetic resonance imaging and/or computed tomography. [source]

    Effects of inhalation of albuterol sulphate, ipratroprium bromide and frusemide on breathing mechanics and gas exchange in healthy exercising horses

    W. M. BAYLY
    Summary The possibility that pre-exercise inhalation of a bronchodilator by healthy horses could improve their mechanics of breathing and enhance performance was investigated. Ipratropium bromide (0.35 ,g/kg bwt; n = 7) was administered by nebulisation 30 min before exercise and frusemide (1 mg/kg bwt; n = 6) was given in the same manner 2 h before exercise. Albuterol sulphate (360 and 720 ,g; n = 7) were administered with a metered dose inhaler 2 h before exercise. Each drug was investigated independently of the others using cross-over protocols. Horses completed incremental exercise tests and oxygen consumption, carbon dioxide production, arterial blood gases, heart rate and measures of breathing mechanics including total pulmonary resistance (RL) and nasopharyngeal resistance (RU) were determined for each exercise intensity. The resistance of the lower airways was calculated subsequently from the difference between RL and RU. None of the drugs tested had an effect on any of the variables measured, possibly because maximal bronchodilation is stimulated in healthy horses by the normal sympathoadrenergic response to exercise. Therefore, the pre-exercise inhalation of a bronchodilator by a healthy horse is unlikely to improve performance capacity. [source]

    A Comparison of Data Sources for Motor Vehicle Crash Characteristic Accuracy

    Robert J. Grant MD
    Abstract. Objective: To determine the accuracy of police reports (PRs), ambulance reports (ARs), and emergency department records (EDRs) in describing motor vehicle crash (MVC) characteristics when compared with an investigation performed by an experienced crash investigator trained in impact biomechanics. Methods: This was a cross-sectional, observational study. Ninety-one patients transported by ambulance to a university emergency department (ED) directly from the scene of an MVC from August 1997 to April 1998 were enrolled. Potential patients were identified from the ED log and consent was obtained to investigate the crash vehicle. Data describing MVC characteristics were abstracted from the PR, AR, and medical record. Variables of interest included restraint use (RU), air bag deployment (AD), and type of impact (TI). Agreements between the variables and the independent crash investigation were compared using kappa. Interrater reliability was determined using kappa by comparing a random sample of 20 abstracted reports for each data source with the originally abstracted data. Results: Agreement using kappa between the crash investigation and each data source was 0.588 (95% CI = 0.508 to 0.667) for the PR, 0.330 (95% CI = 0.252 to 0.407) for the AR, and 0.492 (95% CI = 0.413 to 0.572) for the EDR. Variable agreement was 0.239 (95% CI = 0.164 to 0.314) for RU, 0.350 (95% CI = 0.268 to 0.432) for AD, and 0.631 (95%= 0.563 to 0.698) for TI. Interrater reliability was excellent (kappa > 0.8) for all data sources. Conclusions: The strength of the agreement between the independent crash investigation and the data sources that were measured by kappa was fair to moderate, indicating inaccuracies. This presents ramifications for researchers and necessitates consideration of the validity and accuracy of crash characteristics contained in these data sources. [source]

    ESR isochron dating analyses at Bau de l'Aubesier, Provence, France: Clues to U uptake in fossil teeth

    Bonnie A.B. Blackwell
    At Bau de l'Aubesier, Provence, Mousterian artifacts and human teeth occur in inhomogeneous ("lumpy") sedimentary deposits that include bone and tooth fragments and extensive burnt horizons. Electron spin resonance (ESR) isochron analyses of mammal teeth, which use multiple subsamples with different U concentrations, can measure the external dose rate experienced by the tooth regardless of reworking and sedimentary dose rate changes. Isochron analyses do depend on the U uptake model assumed, but can also identify teeth that have experienced secondary U uptake or leaching. Using 11 teeth from six archaeological layers, the isochrons demonstrate that at least three teeth have experienced secondary uptake. For eight teeth, the U uptake has apparently not followed strictly early (EU), linear (LU), or recent uptake (RU), but more closely approximates LU-RU. Comparing volumetrically averaged sedimentary geochemistry with thermoluminescent dosimetry suggests that fossil tissues in the sediment have also experienced LU-RU uptake. LU-RU uptake can explain standard ESR ages that underestimate the true fossil age. 2001 John Wiley & Sons, Inc. [source]

    Corticosterone shifts different forms of synaptic potentiation in opposite directions

    HIPPOCAMPUS, Issue 6 2005
    Harm J. Krugers
    Abstract Calcium entering the cell via different routes, e.g.,N -methyl- D -aspartate (NMDA) receptors or voltage-dependent calcium channels (VDCCs), plays a pivotal role in hippocampal synaptic potentiation. Since corticosteroid hormones have been reported to enhance calcium influx through VDCCs, one may predict that these hormones facilitate hippocampal synaptic efficacy. Surprisingly, though, stress and corticosteroids have so far been found to reduce synaptic potentiation. Here, we addressed this apparent paradox and examined synaptic potentiation in the CA1 area of hippocampal slices from mice with low basal corticosterone levels 1,4 h after a brief in vitro administration of corticosterone. Nifedipine and APV were used to isolate NMDA receptor-mediated and VDCC-mediated long-term potentiations (LTPs), respectively. We report that corticosterone facilitates synaptic potentiation that depends on activation of VDCCs while impairing synaptic plasticity that is mediated by NMDA receptor activation. The glucocorticoid-receptor (GR) antagonist RU 38486 blocked both the effects of corticosterone. These results indicate that the net effect of corticosteroid hormones on synaptic plasticity is determined by the balance between different types of potentiation, a balance that may be region specific and depends on the experimental conditions. We speculate that these opposite effects on synaptic efficacy are involved in the bidirectional modulation of cognitive performance by corticosteroid hormones. 2005 Wiley-Liss, Inc. [source]

    Rennin-like milk coagulant enzyme produced by a local isolate of Mucor

    Z A Tubesha
    Among 20 isolates of Mucor isolated from various environments in Jordan and found to produce a rennin-like acid protease, known as Mucor rennin-like enzyme (MRE), Mucor J20 was found to produce the highest level of MRE. The optimum incubation conditions for enzyme production in a fortified wheat bran mixture using solid-state fermentation were 3,4 days at 30C. The highest MRE activity (185,200 rennin units or RU) was produced in a medium containing wheat bran and lentil straw (1 : 1 w/w) moistened with whey, and incubated in clay pots at 30C for 4 days. A slightly lower activity value (178 RU) was found when using a mineral salt solution or distilled water instead of whey, or when using wheat bran alone with whey. At pH 4, the MRE retained its complete activity (100%) for 6 weeks at 5C and 10C, and for 3 and 2 weeks at 20C and 30C, respectively. After heating at 60C for 10 min, the enzyme lost its activity at all pH levels used (pH 2,8). The crude extract of MRE was successfully applied in the manufacture of a cheese curd. [source]

    A pilot study of research utilization practices and critical thinking dispositions of Alberta dental hygienists

    SJ Cobban
    Abstract:, In order to test interventions for increasing uptake of research findings into dental hygiene practice, we must first identify factors that influence research use. There has been little work on this topic in dental hygiene, but much in other disciplines that can provide exemplars of how others have approached the study of this phenomenon. Objectives:, A pilot study was conducted to determine if protocols used to study research utilization (RU) behaviours and critical thinking dispositions (CTD) in nursing could also be applied to dental hygiene. Methods:, A cross-sectional survey design was used with a random sample of 640 practicing dental hygienists in Alberta, Canada. Three questionnaires were included: one to capture measures of RU including direct, indirect and symbolic RU; the California Critical Thinking Dispositions Inventory (CCTDI) and a demographics questionnaire. Results:, Mean responses for the three types of RU were highest for indirect at 3.52 (SD 0.720), followed by direct at 3.13 (SD 0.903) and symbolic 2.86 (SD 0.959). The majority (74.8%) scored between 280 and 350 on the CCTDI (maximum 420). Cronbach's alpha reliability for the RU measures and four of the seven sub-scales were over .7, indicating internal consistency reliability. Conclusions:, The instruments proved reliable for this population, but other challenges, including a low response rate, were identified during the process of using the RU questionnaire in the context of dental hygiene practice. Pilot testing identified the need for improvements to the presentation of scales to reduce cognitive load and improve the response rate. [source]

    Combined effects of conjugation pattern and alkoxy side chains on the photovoltaic properties of thiophene-containing PPE-PPVs

    Daniel Ayuk Mbi Egbe
    Abstract This contribution presents the synthesis and properties of four thiophene-containing poly(- p -arylene-ethynylene)/poly(- p -arylene-vinylene)s, PIa-b and PIIa-b, whose repeating units (RU) consist either of 1:2 or 2:2 triple bond/double bond ratio, and which bear linear alkoxy side chains not longer than octyloxy and branched 2-ethylhexyloxy. PIa-b and PIIa-b exhibit similar absorption and emission behaviour in dilute solution (,a = 483,486 nm, ,e = 540 nm) as well as in solid state (,a = 500, 530 nm, ,e = 560 nm), whereby slightly higher fluorescence quantum yields (,f) were obtained for PI than for PII systems, as a result of higher number of thiophene units within the RU of PII. An enhancement of the ,f -value from 0% to 3% is obtained after replacing linear octadecyloxy in PIIc-e by bulky branched 2-ethylhexyloxy in PIIa-b. Nonoptimized solar cells of configuration ITO/PEDOT:PSS/polymer: PCBM (1:3 weight ratio)/LiF/Al show open circuit voltages as high as 900 mV for PIa-b and 800 mV for PIIa-b. Reducing the size of the side chain from R = 2- ethylhexyl in PIa to R = methyl in PIb leads to a significant increase of the short circuit current, ISC, from ca. 2.5 mA to ca. 3.7 mA and consequently to an enhancement of the energy conversion efficiency, ,AM1.5, from ca. 1.2% to ca. 1.7%. This is due to an extended donor-acceptor interfacial area, as evidenced by AFM topology pictures showing smaller nanoscale clusters size in PIb than in PIa active layer. The same change led to minimal effect in PII systems. 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1619,1631, 2007 [source]

    The Effect of Coating Patterns with Spinel-Based Investment on the Castability and Porosity of Titanium Cast into Three Phosphate-Bonded Investments

    Anelise R. F. Pieralini DDS
    Abstract Purpose: This study evaluated the effect of pattern coating with spinel-based investment Rematitan Ultra (RU) on the castability and internal porosity of commercially pure (CP) titanium invested into phosphate-bonded investments. The apparent porosity of the investment was also measured. Materials and Methods: Square patterns (15 15 0.3 mm3) were either coated with RU, or not and invested into the phosphate-bonded investments: Rematitan Plus (RP), Rema Exakt (RE), Castorit Super C (CA), and RU (control group). The castings were made in an Ar-arc vacuum-pressure machine. The castability area (mm2) was measured by an image-analysis system (n = 10). For internal porosity, the casting (12 12 2 mm3) was studied by the X-ray method, and the projected porous area percentage was measured by an image-analysis system (n = 10). The apparent porosity of the investment (n = 10) was measured in accordance with the ASTM C373-88 standard. Results: Analysis of variance (One-way ANOVA) of castability was significant, and the Tukey test indicated that RU had the highest mean but the investing technique with coating increased the castability for all phosphate-bonded investments. The analysis of the internal porosity of the cast by the nonparametric test demonstrated that the RP, RE, and CA with coating and RP without coating did not differ from the control group (RU), while the CA and RE casts without coating were more porous. The one-way ANOVA of apparent porosity of the investment was significant, and the Tukey test showed that the means of RU (36.10%) and CA (37.22%) were higher than those of RP (25.91%) and RE (26.02%). Conclusion: Pattern coating with spinel-based material prior to phosphate-bonded investments can influence the castability and the internal porosity of CP Ti. [source]

    A retrospective survey of outpatients with long-term tracheostomy

    G. Bjrling
    Background:, The Respiratory Unit (RU) at Danderyd University Hospital opened in 1982, with the expressed goal of supporting outpatients with long-term tracheostomy. The primary aim of this retrospective study in tracheostomized patients was to compare the need for hospital care in the 2-year period before and after the tracheostomy. Methods:, Data were collected from patient medical records at the RU, from the National Board of Health and Welfare, Sweden and from the Official Statistics of Sweden. The subjects were RU patients in 1982 (Group 1, n = 27) and in 1997 (Group 2, n = 106) with long-term tracheostomy surviving at least 4 years after the tracheostomy. Results:, Both groups had few and unchanged needs for hospital care after tracheostomy. They spent ,,96% of their time out of hospital. In 1997, (group 2) the number of patients, diagnoses and need for home mechanical ventilation had increased. Life expectancy was assessed for patients in Group 1. Data showed that they lived as long as an age-matched and gender-adjusted control cohort. Conclusions:, Long-term tracheostomy may not increase the need for hospital care and does not reduce life expectancy. These clinical observations were made in a setting where patients had regular access to a dedicated outpatient unit. [source]

    Salivary immunoglobulin A directed to oral microbial GroEL in patients with periodontitis and their potential protective role

    M. Fukui
    The aim of this study was to identify salivary immunoglobulin A (IgA) directed to oral microbial GroEL in patients with periodontitis and to demonstrate their potential protective role through a reduction of inflammatory cytokine production induced by microbial GroEL. Using five different proteins belonging to the heat-shock protein 60 family, Western immunoblot analysis of salivary IgA from 63 subjects revealed immunoreactivities with Campylobacter rectus GroEL and Porphyromonas gingivalis GroEL in subjects with periodontitis (P < 0.05) compared to control subjects. Using the BIACORE 1000 to measure the salivary IgA titers directed towards C. rectus GroEL, high resonance unit (RU) values were observed in the saliva samples from patients with periodontitis (P < 0.01). Furthermore, the number of teeth with deep pocket depth (,5 mm) showed a high correlation coefficient with the RU value (r = 0.50, P < 0.01). C. rectus GroEL possessed the ability to stimulate the production of interleukin-6 by gingival fibroblasts. Interestingly, salivary IgA antibody directed to C. rectus GroEL caused a partial inhibition of interleukin-6 production. This study showed a relationship between high levels of salivary IgA directed to GroEL and periodontal disease severity. Although additional investigations are required, salivary IgA to GroEL may have a protective role by reducing the inflammatory response induced by GroEL derived from periodontopathogenic bacteria. [source]

    Mifepristone (Ru486) Antagonizes Monocyte Chemotactic Protein-3 Down-Regulation at Early Mouse Pregnancy Revealing Immunomodulatory Events in Ru486 Induced Abortion

    Jaya Nautiyal
    Problem:, The survival of an embryo bearing the paternal antigens within the immunocompetent environment of the maternal uterus renders ,pregnancy' to be a state of immunological paradox. The ratio of Th1/Th2 responses is crucial for pregnancy maintenance. Monocyte Chemotactic Protein-3 (MCP3) is a pro-inflammatory, CC chemokine and a Th1 effector which is capable of eliciting significant anti-tumoral immune responses. Method of study:, MCP3 expression was investigated in the murine uterine tissue at different days of initial pregnancy and the effect of RU 486 in immature and delayed implantation model studied using Western blotting and Immunocytochemical techniques. Results and conclusion:, Our results show very high uterine MCP3 expression during pre-implantation followed by a significant MCP3 down-regulation at peri-implantation and low levels of MCP3 during post-implantation period. At the peri-implantation stage, embryos exhibited lowered MCP3 expression when compared with the pre-implantation stage. Ru486, a progesterone antagonist when given in a competitive mode with progesterone resulted in a massive surge in MCP3 expression in both immature mice and delayed implantation models. We hypothesize that it is imperative for MCP3 expression to be down-regulated for the success of pregnancy. The cross-talk between Ru486 and amplified MCP3 expression may be one of the mechanisms by way of which RU486 performs its abortificient and anti tumor role. [source]

    Glucocorticoids Inhibit Diastrophic Dysplasia Sulfate Transporter Activity in Otosclerosis by Interleukin-6

    THE LARYNGOSCOPE, Issue 9 2006
    Yutaka Imauchi MD
    Abstract Hypothesis/Objective: Otosclerosis is a bone remodeling disorder localized to the otic capsule and associated with inflammation. In vitro, increased activity of the diastrophic dysplasia sulf/te transporter (DTDST), which is implicated in bone metabolism, has been reported. Because glucocorticoids modulate the bone turnover and inhibit inflammatory processes, we investigated the effect of dexamethasone (Dex) on interleukin-6 and DTDST in otosclerosis. Study Design: The authors conducted a prospective, case,control study. Materials and Methods: Primary cell cultures were obtained from stapes and external auditory canals in otosclerosis (n = 21) and control patients (n = 18). Assays with [3H]Dex evaluated specific binding sites in otosclerotic and control stapes. The effects of Dex (10,9 to 10,6 M) and RU486 (10,7 M), a glucocorticoid antagonist, were studied on DTDST activity by sulfate uptake. IL-6 secretion was measured in culture media before and after Dex (10,7 M, 24 hours). The effect of IL-6 (10,7 M, 24 hours) was assessed on DTDST activity in control stapes. Results: The number of specific Dex-binding sites was similar in all stapedial cultures. Dex inhibited DTDST activity (19.4 1.02 vs. 29.4 3.94 pmol/,g prot/5 minutes) only in otosclerotic stapes. This effect was dose-dependent, antagonized by RU 486 and only observed 24 hours after Dex exposure. Interleukin (IL)-6 stimulated DTDST activity in normal stapes, whereas Dex inhibited IL-6 production only in otosclerotic stapes. Conclusion: Dex inhibits the DTDST activity, at least in part, through a reduction of IL-6 secretion only in otosclerotic cells. This effect is mediated through the glucocorticoid receptors and may lead to the reduction of bone turnover. [source]

    Modified ureterosigmoidostomy (Mainz Pouch II) in different age groups and with different techniques of ureteric implantation

    BJU INTERNATIONAL, Issue 3 2004
    Patrick J. Bastian
    In this section there are papers on three types of urinary diversion which are in common use. Authors from Germany, Greece and Turkey describe their experience with the Mainz pouch II, S-pouch neobladder and modified Hautmann bladder, respectively. OBJECTIVE To examine the outcome of Mainz Pouch II urinary diversion in different age groups and with different techniques of ureteric implantation. PATIENTS AND METHODS Between March 1995 and August 2002 a Mainz Pouch II was created in 41 patients (27 male and 14 female, median age 56.3 years, range 2,75) with 81 renal units (RU). For analysis, the patients were divided into 29 (70%) aged <65 years and 12 (30%) aged >65 years. Ureteric implantation with the Goodwin-Hohenfellner (GH) technique was used in 55 RU, with the Abol-Enein (AE) modification in 23 and Le-Duc procedure in three. The median (range) follow-up (available for 36 patients, 88%) was 19 (1,80) months. An unvalidated questionnaire was used to determine specific urinary diversion items. RESULTS Early complications occurred in 7% of patients, none requiring surgical intervention. Pyelonephritis occurred in five of 36 patients and seven of 71 RU (14% of the patients, 10% of the RU); all patients were <65 years old. In five of seven RU pyelonephritis was caused by the development of upper urinary tract dilatation; none required surgical revision. Ureteric stenosis requiring reimplantation occurred in two RU (2%, one GH, one AE). All patients were continent in the daytime; all but one patient had to wake to urinate at night, with 36% having to do so more than six times. Of the patients, 63% were able to distinguish between stool and urine. Initially, alkalinizing drugs to prevent metabolic acidosis were taken by 30% of the patients. Of previously medicated patients with a follow-up of >1 year, 8% required oral alkalinizing medication. CONCLUSION The Mainz Pouch II is a safe and reproducible urinary diversion, and serves as a satisfying alternative to other forms of continent urinary diversion in all age groups. The follow-up shows a low complication rate with good results in terms of continence. There were no significant differences in complication rates for the different ureteric implantation techniques. The long-term results remain to be evaluated. [source]

    Sex steroid receptors expression and hormone-induced cell proliferation in human osteosarcoma

    CANCER SCIENCE, Issue 3 2008
    Osamu Dohi
    Sex steroid receptors including estrogen receptors (ER), progesterone receptors (PR), and androgen receptors (AR) have been sporadically reported in human osteosarcoma or its cell lines. Therefore, sex steroids have been considered to play some roles in human osteosarcoma, but no systematic and detailed studies regarding the correlation between the status of these receptors in sarcoma cells and clinicopathological parameters have been reported. We examined the existence of ER, PR and AR in 28 cases of osteosarcoma using immunohistochemistry. We then characterized the potential influence of sex steroids on cell proliferation of osteosarcoma cells using MG-63 human osteosarcoma cell line, which expressed all of these receptors. ER-, and PR were detected in the great majority of the cases (23 and 24 cases, respectively) but ER-, and aromatase were not detected in all the cases, and AR was detected only in eight cases. There was a significant positive correlation between ER-, and Ki-67 (MIB1) labeling indexes. The absence of aromatase in tumors also suggests the relative importance of concentrations of circulating sex steroids. Proliferation of MG-63 cells was significantly stimulated by estradiol, progesterone, and 5,-dihydrotestosterone (DHT), and was significantly suppressed by the addition of fulvestrant (ICI), mifepristone (RU), and hydroxiflutamide, blockers for ER, PR and AR, respectively. Sex steroids, particularly estrogen and progesterone, are considered to play important roles in the regulation of cell proliferation in human osteosarcoma. In addition, these data suggest the potential for a novel endocrine therapy in osteosarcoma using clinically available inhibitors of progesterone and estrogen actions. (Cancer Sci 2008; 99: 518,523) [source]

    Comparison of anti-inflammatory activities of ruscogenin, a major steroidal sapogenin from Radix Ophiopogon japonicus, and Its succinylated derivative, RUS-2HS

    Ya-Lin Huang
    Abstract Ruscogenin (RUS), first isolated from Ruscus aculeatus, is also a major steroidal sapogenin of the traditional Chinese herb Radix Ophiopogon japonicus. It has robust anti-inflammatory activities. In previous studies, a ruscogenin affinity column, derived from succinylated ruscogenin (RUS-2HS), was used to purify an antibody of ruscogenin. A ruscogenin affinity column can also be used to explore its protein targets. However, until now there have been no related pharmacological reports about ruscogenin derivatives. Whether the activity groups of ruscogenin have been blocked during the derivation process remains unknown. The present study was performed to compare the anti-inflammatory activities in vitro of RUS-2HS and ruscogenin. Both compounds reduced tumor necrosis factor-, (TNF-,)-induced adhesion of human pro-myelocytic leukemia cells (HL-60) to endothelial ECV304 cells with IC50 values of 6.90,nM and 7.45,nM, respectively. They were also inhibited overexpression of ICAM-1 in ECV304 cells at the mRNA level as evaluated by real-time PCR and at the protein level evaluated by flow cytometry with similar potency. Such data demonstrate that the functional groups of ruscogenin were not blocked by derivation, suggesting further use of the ruscogenin affinity column for target investigation. Meanwhile, RUS-2HS was found to have remarkable anti-inflammatory activity for the first time, indicating it would be a new lead compound with improved bioavailability. Drug Dev Res 69: 196,202, 2008. 2008 Wiley-Liss, Inc. [source]

    Advanced resonant ultrasound spectroscopy for measuring anisotropic elastic constants of thin films

    H. OGI
    ABSTRACT This paper presents an advanced resonant ultrasound spectroscopy (RUS) method to determine the elastic constants Cij of thin films. Polycrystalline thin films often exhibit elastic anisotropy between the film growth direction and the in-plane direction, and they macroscopically show five independent elastic constants. Because all of the Cij of a deposited thin film affect the mechanical resonance frequencies of the film/substrate layer specimen, measuring resonance frequencies enables one to determine the Cij of the film with known density, dimensions and the Cij of the substrate. Resonance frequencies have to be measured accurately because of low sensitivity of the Cij of films to them. We achieved this by a piezoelectric tripod. Mode identification has to be made unambiguously. We made this measuring displacement,amplitude distributions on the resonated specimen surface by laser Doppler interferometry. We applied our technique to copper thin film and diamond thin film. They show elastic anisotropy and the Cij smaller than bulk values of Cij. Micromechanics calculations indicate the presence of incohesive bonded regions. [source]

    Potential of Eurasian poplar rust to overcome a major quantitative resistance factor

    PLANT PATHOLOGY, Issue 3 2010
    A. Dowkiw
    The effect of RUS, a major quantitative resistance (QR) factor inherited from Populus trichocarpa, was assessed in two Populus deltoides P. trichocarpa F1 progenies against eight isolates of Melampsora larici-populina, the causal agent of Eurasian poplar rust. Six isolates were identified on which RUS had no significant effect. The first RUS -defeating isolate identified suggested a pre-existing potential to overcome RUS in the pathogen's populations. The P. deltoides genetic background made no difference either to the ability of a given isolate to overcome RUS or to the relative and absolute aggressiveness of the isolates. This study illustrates how extreme the isolate-specificity of QR can be. It also yields insights into the relationship between size of uredinia and sporulation rate, discussing the epidemiological significance of spore production per mm2 uredinium. [source]

    Electrochemiluminescence Based on Solid State Tri(4,7-diphenyl-1,10-phenanthroline) Ruthenium(II) Ditetrakis(4-chlorophenyl) Borate Immobilized on Carbon Fibers

    ELECTROANALYSIS, Issue 12 2010
    Chunhua Liu
    Abstract A simple method for immobilization of tri(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) ditetrakis(4-chlorophenyl) borate ([Ru(dpp)3][(4-Clph)4B]2) on carbon fiber electrodes was developed. Excellent electrochemical activity and electrochemiluminescence (ECL) signal of the coated carbon fiber electrodes were observed using oxalate as the co-reactant. In addition, the effects of pH, scan rate, nitrogen and oxygen on ECL intensity were also studied. To demonstrate the reliability, the coated carbon fiber electrodes were used as ECL detectors and very low concentration of phenol was detectable (5.010,8,M). [source]

    Tris(2,2,-bipyridyl)ruthenium(II) Electrogenerated Chemiluminescence Sensor Based on Platinized Carbon Nanotube,Zirconia,Nafion Composite Films

    ELECTROANALYSIS, Issue 12 2010
    Hyun Yoon
    Abstract Mesoporous films of platinized carbon nanotube,zirconia,Nafion composite have been used for the immobilization of tris(2,2,-bipyridyl)ruthenium (II) (Ru(bpy)32+) on an electrode surface to yield a solid-state electrogenerated chemiluminescence (ECL) sensor. The composite films of Pt,CNT,zirconia,Nafion exhibit much larger pore diameter (3.55,nm) than that of Nafion (2.82,nm) and thus leading to much larger ECL response for tripropylamine (TPA) because of the fast diffusion of the analyte within the films. Due to the conducting and electrocatalytic features of CNTs and Pt nanoparticles, their incorporation into the zirconia,Nafion composite films resulted in the decreased electron transfer resistance within the films. The present ECL sensor based on the Pt,CNT,zirconia,Nafion gave a linear response (R2=0.999) for TPA concentration from 3.0,nM to 1.0,mM with a remarkable detection limit (S/N=3) of 1.0,nM, which is much lower compared to those obtained with the ECL sensors based on other types of sol-gel ceramic,Nafion composite films such as silica,Nafion and titania,Nafion. [source]

    Effect of Enzyme and Cofactor Immobilization on the Response of Ethanol Oxidation in Zirconium Phosphate Modified Biosensors

    ELECTROANALYSIS, Issue 10 2010
    Abstract Two different self-contained ethanol amperometric biosensors incorporating layered [Ru(phend)2bpy]2+ -intercalated zirconium phosphate (ZrP) as the mediator as well as yeast -alcohol dehydrogenase (y- ADH) and its cofactor nicotinamide adenine dinucleotide (NAD+) were constructed to improve upon a design previously reported where only this mediator was immobilized in the surface of a modified electrode. In the first biosensor, a [Ru(phend)2bpy]2+ -intercalated ZrP modified carbon paste electrode (CPE) was improved by immobilizing in its surface both y- ADH and NAD+ using quaternized Nafion membrane. In the second biosensor, a glassy carbon electrode was modified with [Ru(phend)2bpy]2+ -intercalated ZrP, y- ADH, and NAD+ using Nafion as the holding matrix. Calibration plots for ethanol sensing were constructed in the presence and absence of ZrP. In the absence of ZrP in the surface of the modified glassy carbon electrode, leaching of ADH was observed as detected by UV-vis spectrophotometry. Ethanol sensing was also tested in the presence and absence of ascorbate to measure the selectivity of the sensor for ethanol. These two ethanol biosensors were compared to a previously reported one where the y -ADH and the NAD+ were in solution, not immobilized. [source]

    Ultrasensitive Eletrogenerated Chemiluminescence Immunoassay by Magnetic Nanobead Amplification

    ELECTROANALYSIS, Issue 3 2010
    Mingyue Li
    Abstract An ultrasensitive electrogenerated chemiluminescence (ECL) immunoassay was proposed by using magnetic nanobeads (MNBs) as the carrier of ECL labels for ECL emission amplification. Carcinoembryonic antigen (CEA) and MNBs were initially immobilized on a platform in 1,:,1 molar ratio via sandwich immunoreaction. Subsequently, the MNBs were released from the platform and labeled with Ru(bpy)32+ species. After the MNBs with Ru(bpy)32+ were immobilized on an Au electrode, ECL of the Ru(bpy)32+ was measured for CEA determination. A linear relation between the ECL intensity and CEA concentration was obtained in a range of 110,14 to 310,13,mol/L (2.0 to 60,pg/mL) with a limit of detection of 8.010,15,mol/L (1.6,pg/mL). [source]

    Electrogenerated Chemiluminescence Sensor Based on Tris(2,2,-bipyridine)ruthenium(II)-Immobilized Natural Clay and Ionic Liquid

    ELECTROANALYSIS, Issue 2 2010
    Ping Jiang
    Abstract A novel electrogenerated chemiluminescence (ECL) sensor based on natural clay and ionic liquid was fabricated. Tris(2,2,-bipyridine)ruthenium(II) (Ru(bpy)32+) was immobilized on natural clay surface through simple adsorption. An ECL sensor was prepared by mixing Ru(bpy)32+ -incorporated clay, graphite powder and an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) as the binder. The electrochemical behavior and ECL of the immobilized Ru(bpy)32+ was investigated. It was observed that the ECL of immobilized Ru(bpy)32+ was activated by the ionic liquid. The proposed ECL sensor showed high sensitivity to tri- n -propylamine (TPrA) and the detection limit was found to be 20,pM. In addition, the ECL sensor displayed good stability for TPrA detection and long-term storage stability. [source]

    Effect of Platinum and Ruthenium Incorporation on Voltammetric Behavior of Nitrogen Doped Diamond-Like Carbon Thin Films

    ELECTROANALYSIS, Issue 23 2009
    W. Khun
    Abstract Nitrogen doped diamond-like carbon thin films with or without platinum and ruthenium incorporation (N-DLC or PtRuN-DLC) were deposited on highly conductive p-Si substrates by DC magnetron sputtering to study the effect of Pt and Ru doping on the voltammetric performance of the N-DLC films. The potential windows of these film electrodes were measured in different electrolytic solutions, such as H2SO4, HCl and KCl. The cyclic voltammograms obtained from the N-DLC film electrodes in these solutions showed wide potential windows while the introduction of Pt and Ru into the film electrodes apparently narrowed down the potential windows due to their catalytic activities. [source]

    Comparison of DNA-Reactive Metabolites from Nitrosamine and Styrene Using Voltammetric DNA/Microsomes Sensors

    ELECTROANALYSIS, Issue 9 2009
    Sadagopan Krishnan
    Abstract Voltammetric sensors made with films of polyions, double-stranded DNA and liver microsomes adsorbed layer-by-layer onto pyrolytic graphite electrodes were evaluated for reactive metabolite screening. This approach features simple, inexpensive screening without enzyme purification for applications in drug or environmental chemical development. Cytochrome P450 enzymes (CYPs) in the liver microsomes were activated by an NADPH regenerating system or by electrolysis to metabolize model carcinogenic compounds nitrosamine and styrene. Reactive metabolites formed in the films were trapped as adducts with nucleobases on DNA. The DNA damage was detected by square-wave voltammetry (SWV) using Ru(bpy) as a DNA-oxidation catalyst. These sensors showed a larger rate of increase in signal vs. reaction time for a highly toxic nitrosamine than for the moderately toxic styrene due to more rapid reactive metabolite-DNA adduct formation. Results were consistent with reported in vivo TD50 data for the formation of liver tumors in rats. Analogous polyion/ liver microsome films prepared on 500,nm silica nanoparticles (nanoreactors) and reacted with nitrosamine or styrene, provided LC-MS or GC analyses of metabolite formation rates that correlated well with sensor response. [source]

    Permselective and Preconcentration Properties of a Surfactant-Intercalated Clay Modified Electrode

    ELECTROANALYSIS, Issue 22 2006
    E. Ngameni
    Abstract This work is focused on the voltammetric examination of the ion exchange properties of a smectite type clay, before and after its modification by the replacement of its native interlamellar cations (Na+, K+, Ca2+) by hexadecyltrimethylammonium cations (HDTMA+). The raw clay and its organically modified form were first characterized by X-ray diffraction (XRD) and N2 adsorption,desorption isotherms (BET method) that confirmed the modification via an intercalation process. These materials were subsequently coated onto glassy carbon surfaces, and the resulting modified electrodes were evaluated for the uptake of [Ru(NH3)6]3+ and [Fe(CN)6]3, ions used as redox probes. Some experimental parameters affecting the incorporation of the probes within the film, including the ionic strength, the surfactant loading and the solution pH are thoroughly examined, in order to highlight the mechanism of the process. The possibility of using the surfactant-intercalated clay modified electrode as an electrochemical sensor for [Fe(CN)6]3, is also evaluated. [source]

    Electrolyte Effects on Charge Transport Behavior of [Os(bpy)2(PVP)10Cl]Cl and [Ru(bpy)2(PVP)10Cl]Cl Redox Polymers in Ultra-Thin Films of Polyions

    ELECTROANALYSIS, Issue 18 2005
    Bingquan Wang
    Abstract Metallopolymer films have important applications in electrochemical catalysis. The alternate electrostatic layer-by-layer method was used to assemble films of [Ru(bpy)2(PVP)10Cl]Cl (denoted as ClRu-PVP) and [Os(bpy)2(PVP)10Cl]Cl (ClOs-PVP) metallopolymers onto pyrolytic graphite electrodes. Film thickness estimated by quartz crystal microbalance was 6,8,nm. The effects of pH, electrolyte species and concentration on the electrochemical properties of these electroactive polymers were studied using cyclic voltammetry (CV). Behavior in various electrolytes was compared. Also the mass changes within the ultra-thin film during redox of Os2+/3+ were characterized by in situ electrochemical quartz crystal microbalance (EQCM). The results indicate rapid reversible electron transfer, and show that both ClRu-PVP and ClOs-PVP have compact surface structures while ClOs-PVP is a little denser than ClRu-PVP. Although hydrogen ions do not participate in the chemical reaction of either film, the movement of Na+ cation and water accompanies the redox process of ClOs-PVP films. [source]

    Fourier Transformed Large Amplitude Square-Wave Voltammetry as an Alternative to Impedance Spectroscopy: Evaluation of Resistance, Capacitance and Electrode Kinetic Effects via an Heuristic Approach

    ELECTROANALYSIS, Issue 15-16 2005

    Abstract A detailed simulation of Fourier transformed large amplitude square-wave voltammetry is presented in the frequency domain for the process Red,Ox+e,. The simulation takes into account the influence of the electrode kinetics (Butler,Volmer model), uncompensated resistance (Ru) and double layer capacitance (Cdl). Of particular significance is the prediction that the even harmonic responses are only detected in the presence of quasi-reversibility or uncompensated resistance, and also are essentially devoid of charging current. In contrast, the DC and odd harmonic AC components exhibit much larger faradaic currents and also contain charging current. Conveniently, detailed analysis of the simulated DC and AC harmonic components reveals the presence of readily recognised patterns of behaviour with unique levels of sensitivity to electrode kinetics, Ru and Cdl, that facilitate quantitative analysis of these terms. These electrochemical parameters are generally calculated by small amplitude impedance spectroscopy and utilisation of linear analysis of equivalent circuits. Experimental studies on the one electron oxidation of ferrocene in dichloromethane (0.1,M Bu4NPF6) and the one electron reduction of [Fe(CN)6]3, in aqueous 0.5,M KCl electrolyte analysed via heuristic forms of data analysis based on recognition of patterns of behaviour, are presented as examples of a reversible process with significant uncompensated resistance and a quasi-reversible process with minimal ohmic drop, respectively. Results demonstrate the advantages of a more intuitively implemented form of data analysis than presently available with conventional forms of impedance spectroscopy. [source]

    Microwave Activation of Electrochemical Processes at Glassy Carbon and Boron-Doped Diamond Electrodes

    ELECTROANALYSIS, Issue 5-6 2005
    Kumar Sur, Ujjal
    Abstract Voltammetric experiments under intense microwave field conditions have been carried out at a carbon microfiber electrode, an array of carbon microfiber electrodes, and at a boron-doped diamond electrode. For the reversible one electron redox systems Fe(CN) and Ru(NH3) in aqueous KCl solution increased currents (up to 16 fold at a 33,,m diameter carbon microelectrode) and superheating (up to ca. 400,K at all types of electrodes) are observed. Electrodes with smaller diameter allow better signal enhancements to be achieved. From the missing effect of the supporting electrolyte concentration on the microwave enhanced currents, it can be concluded that effects observed at carbon electrodes (microwave absorbers) are due to the interaction of microwaves with the electrode material whereas for metal electrodes (microwave conductors) effects are dominated by the interaction of the microwaves with the aqueous dielectric. Short heat pulses can be applied by pulsing the microwave field and relatively fast temperature transients are observed for small electrodes. For the irreversible two electron oxidation of L -dopa in aqueous phosphate buffer, different types of effects are observed at glassy carbon and at boron-doped diamond. Arrays of carbon microfibers give the most reproducible and analytically useful current signal enhancements in the presence of microwaves. [source]