RUE Values Research Articles

Novel Ruthenium(II) and Gold(I) NHC Complexes: Synthesis, Characterization, and Evaluation of Their Anticancer Properties

The synthesis, characterization, and biological evaluation of novel Ru(II)- and Au(I)-N-heterocyclic carbenes is reported. The NHC-ruthenium(II) complexes (1–6) were synthesized by reacting the appropriately substituted imidazolium bromides with Ag2O, forming the NHC-silver bromide in situ followed by transmetalation with dimeric p-cymene ruthenium(II) dichloride. In an analogous manner the NHC-gold(I) chloride complexes (NHC-Au(I)Cl) 7–9 were synthesized, utilizing dimethylsulfido gold(I) chloride as the transmetalating agent. The ligand exchange on the NHC-gold(I) chlorides was achieved by either reacting the complexes with silver acetate to yield the NHC-gold(I) acetates (NHC-Au(I)OAc) 10–12 or reacting the NHC-gold(I) chlorides under basic conditions with 2′,3′,4′,6′-tetra-O-acetyl-1-thio-β-d-glucopyranose (SR) to give the NHC-gold(I)-(2′,3′,4′,6′-tetra-O-acetyl-β-d-glucopyranosyl-1-thiolate) complexes (NHC-Au(I)SR) 13–15. The Ru(II)-NHC complex 1 and the Au(I)-NHC complex 9 were characterized by single-crystal X-ray diffraction. Also the IC50 values of these 15 complexes were determined by an MTT-based assay against the human cancer cell lines Caki-1 (renal) and MCF-7 (breast). The Ru(II) complexes 1–6 revealed the following IC50 values against Caki-1 of >500, 94 (±5), 93 (±2), 170 (±20), 39 (±5), and 13 (±2) μM and against MCF-7 of >500, 80 (±15), 19 (±1), 7.1 (±1.2), 2.4 (±0.7), and 7.0 (±1.2) μM, respectively. IC50 values of 67 (±7), 16 (±2), 41 (±1), 31 (±2), 42 (±5), 18 (±1), 14 (±2), 17 (±2), and 58 (±2) μM against Caki-1 and 8.4 (±0.4), 30 (±3), 12 (±1), 23 (±3), 12 (±1), 25 (±3), 6.1 (±1.5), 9.3 (±1.6), and 14 (±2) μM against MCF-7 were found for the Au(I) complexes 7–15.

Estimation of electrode kinetic and uncompensated resistance parameters and insights into their significance using Fourier transformed ac voltammetry and e-science software tools

In transient forms of voltammetry, quantitative analysis of electrode kinetics and parameters such as uncompensated resistance (Ru) and double layer capacitance (Cdl) are usually undertaken by comparing experimental and simulated data. Commonly, the skill of the experimentalist is heavily relied upon to decide when a good fit of simulated to experimental data has been achieved. As an alternative approach, it is now shown how data analysis can be based on implementation of e-science software tools. Previously, a standard heuristic data analysis approach applied to the oxidation of ferrocene in acetonitrile (0.1M Bu4NPF6) at a glassy carbon electrode using higher order harmonics available in Fourier transformed ac voltammetry implied that the heterogeneous charge transfer rate constant k0 is ⩾0.25cms−1 with the charge transfer coefficient (α) lying in the range of 0.25–0.75. Application of e-science software tools to the same data set allows a more meaningful understanding of electrode kinetic data to be provided and also offers greater insights into the sensitivity of the IRu (Ohmic drop) on these parameters. For example, computation of contour maps based on a sweep of two sets of parameters such as k0 and Ru or α and k0 imply that α is 0.50±0.05 and that k0 lays in the range 0.2–0.4cms−1 with Ru around 130Ohm. Quantitative evaluation of k0, α and Ru for the quasi-reversible [Fe(CN)6]3-+e⇌[Fe(CN)6]4- process at a glassy carbon electrode in aqueous media is also facilitated by use of e-science software tools. In this case, when used in combination with large amplitude Fourier transformed ac voltammetry, it is found for each harmonic that k0 for the electrode process lies close to 0.010cms−1, α is 0.50±0.05 and Ru is ⩽10Ohm.

Fuel Cells Catalyst for Start-Up and Shutdown Conditions: Electrochemical, XPS, and STEM Evaluation of Sputter-Deposited Ru, Ir, and Ti on Pt-Coated Nanostructured Thin Film Supports

Minute amounts of Ru, Ir, and Ti (2 and 10 μg/cm2) sputter-deposited over 3M Pt-coated nanostructured thin film (NSTF) substrate were evaluated as oxygen evolution reaction (OER) catalysts in a polymer electrolyte membrane (PEM) environment. The purpose of the study was to explore the suitability of these elements for modifying both the anode and the cathode catalysts in order to lower the overpotential for the oxidation of water during transient conditions. By keeping the electrode potential as close as possible to the thermodynamic potential for OER, other components in the fuel cell, such as platinum, the gas diffusion layer, and the bipolar plates, will be less prone to degradation. While Ru and Ir were chosen due to their high OER activity in aqueous environment, Ti was also included due to its ability to stabilize the OER catalysts. The 3M Pt-NSTF was selected as a stable, carbon-free substrate. The surface chemistry and the morphology of OER catalysts on Pt-NSTF were examined by X-ray photoelectron spectroscopy and scanning transmission electron microscopy. The OER catalytic activity of Ru and Ir in PEMs compares well with their behavior in aqueous environment. It was found that Ru is more active than Ir, that Ir is considerably more stable, while the mass activity of both is higher in comparison with similar OER catalysts.

Catalyst Durability for Fuel Cells under Start-Up and Shutdown Conditions: Evaluation of Ru and Ir Sputter-Deposited Films on Platinum in PEM Environment

Electrochemical and surface properties of Ru, Ir and Ti over-layers sputter-deposited onto 3M Pt-coated nano-structured thin film (NSTF) substrate were evaluated in PEM environment. Ti was included because it is often combined with Ru and Ir to improve stability of these highly active catalysts for oxygen evolution reaction (OER). Different OER catalyst coating thicknesses were formed by varying Ru, Ir and Ti mass in the range of 1-10 µg/cm2 per Pt-NSTF geometric area. The OER activity was assessed by quasi-steady state polarization measurements. The electrochemical data demonstrate that the OER catalytic activity of Ru and Ir in PEM compares well with their behavior in aqueous environment. The OER catalysts composition on Pt-NSTF was characterized by XPS. The XPS results indicate the organo-metallic bonds formation at the interface of Ru OER catalysts with Pt-NSTF.

Catalyst Durability for Fuel Cells under Start-Up and Shutdown Conditions: Evaluation of Ru and Ir Sputter-Deposited Films on Platinum in PEM Environment

not Available.

Antiproliferative activity of dmoPTA–Ru(II) complexes against human solid tumor cells

The biological evaluation of new Ru(II) complexes carrying dmoPTA (dmoPTA=3,7-dimethyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane) ligands is reported. The results on the biological activity revealed that the organometallic complexes are active against all cell lines with GI(50) values in the range 1.1-2.6 μM. When compared to the standard anticancer drug cisplatin, the bimetallic Ru(II) complexes showed a greater activity profile. The cell cycle analysis revealed that the new compounds induced arrest in G(1) phase. Contrary to cisplatin, these Ru(II) complexes do not interact with DNA. This result suggests that DNA might not be the key pharmacological target.

Electrical Evaluation of Ru–W(-N), Ru–Ta(-N) and Ru–Mn films as Cu diffusion barriers

Co-sputtered Ru-Ta(N), Ru-W(N) and Ru-Mn composites are investigated in terms of their barrier properties against Cu diffusion. A wide range of stoichiometries is analyzed with regard to crystallization, barrier properties, resistivity, Cu adhesion and direct Cu plating behaviour. All films were annealed at 350^oC and 600^oC in forming gas for 1h and subsequently stressed at elevated temperatures and electrical fields (BTS, 250^oC, 2MV/cm, 30min). The leakage current was monitored during BTS to observe increased leakage due to Cu diffusion. The Cu ions that eventually have passed the barrier and drifted into the dielectric of the MIS test structure were detected and quantified using the triangular voltage sweep method. The addition of 10% W or Ta into a Ru film already leads to a highly improved barrier performance against Cu diffusion, comparable to TaN, as long as the temperatures involved are kept below 350^oC. Outstanding barriers were identified after 600^oC annealing and subsequent BTS, among them Ru50W50, Ru50Ta50 and Ru95Mn5. However, only Ru90Ta10 and Ru95Mn5 offer an excellent Cu adhesion and the possibility of direct Cu plating.

Analysis of trends in the Sahelian ‘rain-use efficiency’ using GIMMS NDVI, RFE and GPCP rainfall data

Rain-use efficiency (RUE; the ratio of vegetation productivity to annual precipitation) has been suggested as a measure for assessing land degradation in arid/semi-arid areas. In the absence of anthropogenic influence, RUE has been reported to be constant over time, and any observed change may therefore be attributed to non-rainfall impacts. This study presents an analysis of the decadal time-scale changes in the relationship between a proxy for vegetation productivity (ΣNDVI) and annual rainfall in the Sahel-Sudanian zone of Africa. The aim is to test the quality of data input and the usefulness of both the RUE approach and an alternative method for separating the effects on vegetation productivity of rainfall change and human impact. The analyses are based on earth observation of both rainfall (GPCP (Global Precipitation Climatology Project), 1982–2007 and RFE (Rainfall Estimate) (1996–2007)) and ΣNDVI (AVHRR GIMMS NDVI dataset, 1982–2007). It is shown that the increase in ΣNDVI has been substantial in the Sahel-Sudanian zone over the 1982–2007 period, whereas for the period 1996–2007 the pattern of ΣNDVI trends is more complex. Also, trend analysis of annual rainfall from GPCP data (2.5° resolution) and RFE data (0.1° resolution) suggests that rainfall has increased over both periods. Further it is shown that RUE values are highly correlated to rainfall, undermining the use of earth observation (EO)-based RUE (using ΣNDVI) as a means of separating rainfall impacts from other factors. An alternative method identify temporal trends in residuals of ΣNDVI, after regressing it against annual rainfall, is tested, yet is shown to be useful only where a high correlation between ΣNDVI and annual rainfall exists. For the areas in the Sahel-Sudanian zone for which this condition is fulfilled, trend analyses suggest very limited anthropogenic land degradation in the Sahel-Sudanian zone.

Modelling Biomass Accumulation and Partitioning in Chickpea (Cicer arietinum L.)

AbstractQuantitative information regarding biomass accumulation and partitioning in chickpea (Cicer arietinum L.) is limited or inconclusive. The objective of this study was to obtain baseline values for extinction coefficient (KS), radiation use efficiency (RUE, g MJ−1) and biomass partitioning coefficients of chickpea crops grown under well‐watered conditions. The stability of these parameters during the crop life cycle and under different environmental and growth conditions, caused by season and sowing date and density, were also evaluated. Two field experiments, each with three sowing dates and four plant densities, were conducted during 2002–2004. Crop leaf area index, light interception and crop biomass were measured between emergence and maturity. A KS value of 0.5 was obtained. An average RUE of 1 g MJ−1 was obtained. Plant density had no effect on RUE, but some effects of temperature were detected. There was no effect of solar radiation or vapour pressure deficit on RUE when RUE values were corrected for the effect of temperature. RUE was constant during the whole crop cycle. A biphasic pattern was found for biomass partitioning between leaves and stems before first‐seed stage. At lower levels of total dry matter, 54 % of biomass produced was allocated to leaves, but at higher levels of total dry matter, i.e. under favourable and prolonged conditions for vegetative growth, this portion decreased to 28 %. During the period from first‐pod to first‐seed, 60 % of biomass produced went to stems, 27 % to pods and 13 % to leaves. During the period from first‐seed to maturity, 83 % of biomass was partitioned to pods. It was concluded that using fixed partitioning coefficients after first‐seed are not as effective as they are before this stage. Environmental conditions (temperature and solar radiation) and plant density did not affect partitioning of biomass.

The response of autumn and spring sown sugar beet ( Beta vulgaris L.) to irrigation in Southern Italy: Water and radiation use efficiency

The Apulia region in Southern Italy is an important area for sugar beet cultivation. It is characterised by clay soils and a hot-arid and winter-temperate climate. The capability of sugar beet to exploit solar radiation, water use and irrigation supply in root yield, total dry matter and sucrose production was studied and analysed in relation to two experimental factors: sowing date – autumn (October–December) and spring (March) – and irrigation regime – optimal and reduced (respectively with 100 and 60% of actual evapotranspiration). Data sets from three experiments of spring sowing and three of autumn sowing were used to calculate: (1) water use efficiency in the conversion in dry matter (WUE dm, plant dry matter at harvest versus seasonal water use ratio), in sucrose (WUE suc, sucrose yield versus seasonal water use ratio); (2) irrigation water use efficiency in the conversion in dry matter (IRRWUE dm), in sucrose (IRRWUE suc) and fresh root yield (IRRWUE fr); and (3) radiation use efficiency (RUE, plant dry matter during the crop cycle and at harvest versus intercepted solar radiation ratio). Autumnal beet was more productive than spring for fresh root, plant total dry matter, sucrose yield and concentration; also WUE suc and IRRWUE s were higher in the autumnal sugar beet, but no difference was observed in WUE dm (on average, 2.83 g of dry matter kg −1 of water used). An average saving of about 26% of seasonal irrigation supply (equivalent to about 100 mm) was measured in the three years with the earliest sowing time. The optimal irrigation regime produced higher root yield, plant total dry matter and sucrose yield than the reduced one; on the contrary the IRRWUE fr and IRRWUE dm were higher in the reduced irrigation strategy. WUE s and IRRUWE s correlated positively with the length of crop cycle, expressed in growth degree days and, in particular, to the length of the period from full soil cover canopy to crop harvest, the period when plant photosynthetic activity and sucrose accumulation are at maximum rates. Seasonal RUE was higher in the spring than in the autumn sowing (1.14 μg J −1 versus 1.00 μg J −1). The RUE values during the crop cycle reached the maximum in the period around complete canopy soil cover. The results showed the importance for better use of water and radiation resources of autumnal sowing time and of reduced irrigation regime in sugar beet cropped in a Mediterranean environment.

Beware of comparing RUE values calculated from PAR vs solar radiation or absorbed vs intercepted radiation

The concept of radiation-use efficiency (RUE: biomass produced/energy intercepted by a crop) is commonly used for analysis and modelling of crop growth. The various values found in the literature have not, however, been calculated in the same way. This paper focuses on two aspects that account for differences in the published values. First, the differential effect of canopy development on radiation interception and hence on RUE calculated from photosynthetically active radiation (PAR) and overall solar radiation, respectively. Second, the differences in RUE values calculated from absorbed as compared with intercepted radiation. The analyses reveal why it is difficult to make precise comparisons of published values of RUE and why the biggest differences are found for crops with small LAI or with long LAI establishment phase.

Leaf Nitrogen Content and Minimum Temperature Interactions Affect Radiation‐Use Efficiency in Peanut

Reproductive development in peanut (Arachis hypogaea L.) is generally characterized by progressively declining leaf N content. A nonnodulating genotype and three nodulating cultivars were grown at two locations contrasting primarily in night temperature to derive critical levels of leaf N necessary for maintenance of dry matter (DM) accumulation rates. Nonnodulating plants were grown in field plots with four N treatments ranging from 0 g N m−2 (with 1.0 kg m−2 finely chopped cereal straw) to 26.0 g N m−2. The accumulation of DM and N were monitored for two sowing dates in the cooler environment and at a single sowing in the warm environment. Early sowing in the cool environment (early‐cool) resulted in the nonnodulating genotype accumulating similar levels of DM at high N to the comparable treatment in the warm environment (early‐warm), but crop duration in SD1 was 31 d longer. Crop development and DM accumulation were restricted in the second sowing in the cool environment (late‐cool) due to a frost. Slower DM accumulation in early‐cool was related to both reduced interception of incident photosynthetically active radiation, due to slow leaf area development, and to a 20% lower conversion efficiency of intercepted radiation to DM (RUE). The lower RUE in the two cool environments may have been caused by the low minimum temperature. Responsiveness of RUE to the total amount of N per unit leaf area (SLN) was negligible in the two cool environments. Nodulating cultivars grown at the same locations and sowing dates had similar SLN and RUE values as the non‐nodulating genotype grown under the high N treatment.

Irrigated spring wheat and timing and amount of nitrogen fertilizer. II. Physiology of grain yield response

In order to understand the mechanism by which the timing and amount of N fertilizer affect grain yield of wheat, a large experiment comprising 32 N treatments (from nil to 320 kg N ha −1, applications from seeding to booting) was conducted using a high-yielding semidwarf spring cultivar grown under low natural fertility at Griffith, New South Wales (34°S). The weather was close to normal and supplemental spring irrigations eliminated the possibility of water stress. Crop management was otherwise optimal and there was no disease or lodging. Grain yield ranged from 170 to 750 g m −2 across N fertilizer treatments the response to N was not reduced with applications as late as the onset of stem elongation. Grain yield was very closely correlated with kernels m −2 and with total biomass production. Kernel number was in turn closely correlated with spike dry weight (g m −2) at anthesis and with crop dry weight accumulation during the spike growth phase commencing 1 week before fag leaf emergence. Kernels per unit spike weight was unaffected by N but dry matter partitioning to spikes as increased by early N stress. Numerical components of kernel number did not give a useful quantitative explanation of these N responses. Delay in N application up until the onset of stem elongation did not limit N response because N uptake and leaf area responded quickly enough for close to full radiation interception to be reached before the onset of spike growth. Crop dry weight accumulation, generally directly related to absorbed photosynthetically-active radiation (PAR A), was also assisted by small increases in radiation-use-efficiency (RUE, g top dry matter MJ −1 PAR A) with higher N content in foliage. Peak RUE values (mean 2.86±0.03 g MJ −1) were close to other published values for wheat. The apparent recovery of N fertilizer was little affected by N amount and timing (average 63%). N uptake continued throughout grain filling in almost all treatments but especially those with late applications. N-utilization efficiency (grain yield/N uptake), however, declined with large N doses and with applications after the onset of stem elongation: values ranged from 30 to 60 g g −1. Utilization efficiency declines were largely associated with increases in grain N concentration and, to a lesser extent, reinforcing decreases in N harvest index.

Variability in crop radiation-use efficiency associated with vapor-pressure deficit

The ratio of the amount of crop dry-matter produced per unit of intercepted photosynthetically active radiation is usually referred to as radiation-use efficiency ( rue ). Large within-species variability in rue has been reported for a number of species growing with adequate moisture and nutrients. This variability raises questions concerning the generality of the approach for plant-growth analysis and modeling. Available data suggest that increased vapor-pressure difference between substomatal air and the air surrounding the leaves may lead to reductions in leaf conductance and photosynthetic capacity of well-watered plants, and therefore to rue reductions. The coefficient of determination ( r 2 ) of linear regressions of reported rue values as a function of daily saturation vapor-pressure deficit ( Δe ) were calculated for sorghum ( Sorghum bicolor (L.) Moench) and maize ( Zea mays ). Decreased rue was associated with increased Δe in well-watered conditions, explaining a large portion of the rue variability. Effects of Δe should be considered when the rue concept is used to estimate biomass accumulation.

Noncompetitive antiestrogenic effect of RU 486 in blocking the estrogen-stimulated luteinizing hormone surge and the proliferative action of estradiol on endometrium in castrate monkeys

The noncompetitive antiestrogenic effects of RU 486 were examined using estradiol (E2)-treated ovariectomized monkeys given RU 486, progesterone (P), or both. The E2-induced luteinizing-hormone (LH) surge of control animals was abrogated by P and/or RU 486. Secretory transformation by P was inhibited by RU 486 coadministration. RU 486 alone (1 mg/kg) induced endometrial secretory transformation, but higher doses (5 mg/kg) inhibited proliferation and secretory activity. Thus in the presence of P, RU 486 is antagonistic but, in absence of P, exhibits endometrial progestational effects at low doses and an antiproliferative (antiestrogenic) effect at higher doses. These data encourage continued evaluation of RU 486 as a potential contraceptive agent acting at the pituitary and/or endometrial level.

LABORATORY AND CLINICAL EVALUATION OF RU 28965 (ROXITHROMYCIN) IN RESPIRATORY TRACT INFECTIONS

LABORATORY AND CLINICAL EVALUATION OF RU 28965 (ROXITHROMYCIN) IN RESPIRATORY TRACT INFECTIONS

LABORATORY AND CLINICAL EVALUATION OF RU 28965 IN DERMATOLOGY

LABORATORY AND CLINICAL EVALUATION OF RU 28965 IN DERMATOLOGY

Laboratory and clinical evaluation of RU 28965 in respiratory infections

Laboratory and clinical evaluation of RU 28965 in respiratory infections