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Publication
Journal: Chemistry - A European Journal
March/11/2012
Abstract
The new compounds LiLn(9)Mo(16)O(35) (Ln=La, Ce, Pr, and Nd) were synthesized from stoichiometric mixtures of Li(2)MoO(4), Ln(2)O(3), Pr(6)O(11) or CeO(2), MoO(3), and Mo heated at 1600 °C for 48 h in a molybdenum crucible sealed under a low argon pressure. The crystal structure, determined from a single crystal of the Nd member, showed that the main building block is the Mo(16)O(36) unit, the Mo(16) core of which is totally new and results from the fusion of two bioctahedral Mo(10) clusters. It can also be viewed as a fragment of an infinite twin chain of edge-sharing Mo(6) octahedra. The Mo(16)O(36) cluster units share some oxygen atoms to form infinite chains running parallel to the b axis, which are separated by the rare-earth and lithium cations. (7)Li-NMR experiments, carried out at high field on the nonmagnetic LiLa(9)Mo(16)O(35), provided insights into the local environment of the lithium ions. Magnetic susceptibility measurements confirmed the trivalent oxidation state of the magnetic rare-earth cations and indicated the absence of localized moments on the Mo(16) clusters. The electronic structure of the LiLn(9)Mo(16)O(35) compounds was analyzed using molecular and periodic quantum calculations. The study of the molecular orbital diagrams of isolated Mo(16)O(36) models allowed the understanding of this unique metallic architecture. Periodic density functional theory calculations demonstrated that few interactions occur between the Mo(16) clusters, and predicted semiconducting properties for LiLn(9)Mo(16)O(35) as a band gap of 0.57 eV was computed for the lanthanum phase.
Publication
Journal: Molecular Reproduction and Development
June/15/2005
Abstract
The present study was carried out to assess the possible role of mitogen-activated protein kinase (MAPK) in the meiosis-inducing action of the AMP-activated protein kinase (AMPK) activator, 5-aminoimidazole-4-carboxamide 1-beta-ribofuranoside (AICAR). Cumulus cell-enclosed oocytes (CEO) or denuded oocytes (DO) from immature, eCG-primed mice were cultured 4 hr in Eagle's minimum essential medium containing dbcAMP plus increasing concentrations of AICAR or okadaic acid (OA). OA is a phosphatase inhibitor known to stimulate both meiotic maturation and MAPK activation and served as a positive control. Both OA and AICAR were potent inducers of meiotic resumption in mouse oocytes and brought about the phosphorylation (and thus, activation) of MAPK, but by different kinetics: MAPK phosphorylation preceded GVB in OA-treated oocytes, while that resulting from AICAR treatment appeared only after GVB. The MEK inhibitors, PD98059 and U0126, blocked the meiotic resumption induced by AICAR but not that induced by OA. Although the MEK inhibitors suppressed MAPK phosphorylation in both OA- and AICAR-treated oocytes, meiotic resumption was not causally linked to MAPK phosphorylation in either group. Furthermore, AICAR-induced meiotic resumption in Mos-null oocytes (which are unable to stimulate MAPK) was also abrogated by PD98059 treatment. A non-specific effect of the MEK inhibitors on AICAR accessibility to the oocyte was discounted by showing that they failed to suppress either nucleoside uptake or AICAR-stimulated phosphorylation of acetyl CoA carboxylase (ACC), a substrate of AMPK. The suppression of AICAR-induced maturation by MEK inhibitors must, therefore, be occurring by actions unrelated to MEK stimulation of MAPK; consequently, it would be prudent to consider this possible non-specific action of the inhibitors when they are used to block MAPK activation in mouse oocytes.
Publication
Journal: Journal of Hazardous Materials
December/14/2019
Abstract
Cerium dioxide nanoparticles (CeO2NPs) has been widely used in many fields, and also recommended as a promising carrier for cancer targeted drugs in human medicine for its excellent properties. However, its biological safety to human health remains controversial. In this study, we propose a mouse model exposed to CeO2NPs during early pregnancy, to clarify the effect of maternal CeO2NPs exposure and related molecular mechanism. Pregnant mice are injected intravenously with CeO2NPs by once a day on D5, D6, and D7. The effects of CeO2NPs exposure on pregnancy outcomes are observed on D8, D9, D10 and D12. The results show that CeO2NPs exposure during early pregnancy would lead to poor pregnancy outcomes. Further study find that low-quality decidualization, including the imbalance of trophoblast invasion regulators secreted by decidual cells and abnormal recruitment and differentiation of uNK cells, leads to subsequent biological negative "ripple effects", including placental dysfunction, fetal loss or growth restriction. This study broadens the understanding of the biological safety of CeO2NPs, and provide clues for the prevention of its negative biological effects. Improving the function of uNK cells can be used as one of the therapeutic targets to prevent negative effects of CeO2NPs on pregnancy.
Publication
Journal: Biosensors and Bioelectronics
May/25/2009
Abstract
A new horseradish peroxidase (HRP) third-generation electrochemical biosensor based on ceria nanocubes (CeO(2)-NCs) and chitosan (Chit) was developed. The single-crystalline, uniform and size-controlled CeO(2)-NCs have been synthesized by hydrothermal method. HRP was immobilized in CeO(2)-NCs and Chit film on the glass carbon electrode (HRP/CeO(2)/Chit/GCE). Compared with HRP-chitosan modified electrode (HRP/Chit/GCE), HRP/CeO(2)/Chit/GCE exhibited a pair of more obvious redox peaks at -0.348 V (versus Ag/AgCl). Experimental results indicate CeO(2)-NCs greatly promoted the electron transfer between HRP and GCE. The immobilized HRP exhibited direct electrochemical behavior toward the reduction of hydrogen peroxide (H(2)O(2)). The resulting biosensor showed a linear range of 1-150 microM and a detection limit of 0.26 microM estimated at a signal-to-noise ratio of 3. Stability and reproducibility of the biosensor were also studied. The biological activity of HRP immobilizing in the composite film was characterized by UV-vis and FTIR spectra.
Publication
Journal: Harvard Business Review
July/10/2007
Abstract
In search of lessons to apply in our own careers, we often try to emulate what effective leaders do. Roger Martin says this focus is misplaced, because moves that work in one context may make little sense in another. A more productive, though more difficult, approach is to look at how such leaders think. After extensive interviews with more than 50 of them, the author discovered that most are integrative thinkers -that is, they can hold in their heads two opposing ideas at once and then come up with a new idea that contains elements of each but is superior to both. Martin argues that this process of consideration and synthesis (rather than superior strategy or faultless execution) is the hallmark of exceptional businesses and the people who run them. To support his point, he examines how integrative thinkers approach the four stages of decision making to craft superior solutions. First, when determining which features of a problem are salient, they go beyond those that are obviously relevant. Second, they consider multidirectional and nonlinear relationships, not just linear ones. Third, they see the whole problem and how the parts fit together. Fourth, they creatively resolve the tensions between opposing ideas and generate new alternatives. According to the author, integrative thinking is an ability everyone can hone. He points to several examples of business leaders who have done so, such as Bob Young, cofounder and former CEO of Red Hat, the dominant distributor of Linux opensource software. Young recognized from the beginning that he didn't have to choose between the two prevailing software business models. Inspired by both, he forged an innovative third way, creating a service offering for corporate customers that placed Red Hat on a path to tremendous success.
Publication
Journal: Harvard Business Review
June/30/2009
Abstract
If there's one thing that the past decade's business disasters should teach us, it's that we need to stop evaluating corporate leaders simply on the basis of how much wealth they create for investors. A healthier yardstick would be this: the extent to which leaders create firms that are economically, ethically, and socially sustainable. The first step toward accomplishing that task is to create a culture of candor. Companies can't innovate, respond to stakeholder needs, or run efficiently unless the people inside them have access to timely, relevant information, point out professors O'Toole, of the University of Denver's Daniels College of Business, and Bennis, of the University of Southern California. Increasing transparency can be an uphill battle against human nature, however. The obstacles are numerous: macho executives who don't listen to their subordinates or punish them for bringing bad news; leaders who believe that information is power and hoard it; groupthink among team members who don't know how to disagree; boards that fail to question charismatic CEOs. Nevertheless, leaders can take steps to nurture transparency. By being open and candid, admitting their errors, encouraging employees to speak truth to power, and rewarding contrarians, executives can model the kind of conduct they want to see. Training employees to handle unpleasant conversations with grace also will break down barriers to honest communication. To avoid being blinded by biases, leaders can diversify their sources of information--an obvious measure that's rarely taken. Perhaps the biggest lever for cultural change is the executive selection process--choosing leaders for their transparent behavior, not just their ability to compete. And a few companies have even gone so far as to share all relevant information with every employee.
Publication
Journal: Harvard Business Review
April/15/2007
Abstract
The ongoing problems in business leadership over the past five years have underscored the need for a new kind of leader in the twenty-first century: the authentic leader. Author Bill George, a Harvard Business School professor and the former chairman and CEO of Medtronic, and his colleagues, conducted the largest leadership development study ever undertaken. They interviewed 125 business leaders from different racial, religious, national, and socioeconomic backgrounds to understand how leaders become and remain authentic. Their interviews showed that you do not have to be born with any particular characteristics or traits to lead. You also do not have to be at the top of your organization. Anyone can learn to be an authentic leader. The journey begins with leaders understanding their life stories. Authentic leaders frame their stories in ways that allow them to see themselves not as passive observers but as individuals who learn from their experiences. These leaders make time to examine their experiences and to reflect on them, and in doing so they grow as individuals and as leaders. Authentic leaders also work hard at developing self-awareness through persistent and often courageous self-exploration. Denial can be the greatest hurdle that leaders face in becoming self-aware, but authentic leaders ask for, and listen to, honest feedback. They also use formal and informal support networks to help them stay grounded and lead integrated lives. The authors argue that achieving business results over a sustained period of time is the ultimate mark of authentic leadership. It may be possible to drive short-term outcomes without being authentic, but authentic leadership is the only way to create long-term results.
Publication
Journal: Trustee : the journal for hospital governing boards
December/17/1985
Abstract
In a previous issue of Trustee the author wrote that hospitals must re-examine board structure, size, and composition, as well as management authority and CEO/board relationships if they are to emulate the business world. (See "If Boards Mean Business, They'll Refocus the Governance Function," April 1983.) This article brings the earlier work up to date and reports the results of a survey that shows the status of those changes in one major state: Ohio.
Authors
Publication
Journal: Nanotechnology
May/31/2011
Abstract
Cerium(IV) oxide nanoparticles were synthesized using an inverse miniemulsion technique with cerium nitrate hexahydrate as precursor. The resulting nanocrystallites are as small as 5 nm with a specific surface area of 158 m² g⁻¹ after calcination at 400 °C. With the addition of cetyltrimethylammonium bromide (CTAB) or (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide)) triblock copolymers (PEO-PPO-PEO) as template in the miniemulsion droplets, the specific surface area can be increased up to 255 m² g⁻¹. The miniemulsions were characterized by dynamic light scattering (DLS) and the obtained oxides were examined by x-ray diffraction (XRD), nitrogen sorption (BET and BJH), and transmission electron microscopy (TEM). The catalytic activity of the resulting ceria was investigated for the temperature-programmed oxidation (TPO) of methane.
Publication
Journal: Toxicological Sciences
June/10/2003
Abstract
A physiologically based pharmacokinetic (PBPK) model of acrylonitrile (ACN) and cyanoethylene oxide (CEO) disposition in humans was developed and is based on human in vitro data and scaling from a rat model (G. L. Kedderis et al., 1996, TOXICOL: Appl. Pharmacol.140, 422-435) for application to risk assessment. All of the major biotransformation and reactivity pathways, including metabolism of ACN to glutathione conjugates and CEO, reaction rates of ACN and CEO with glutathione and tissues, and the metabolism of CEO by hydrolysis and glutathione conjugation, were described in the human PBPK model. Model simulations indicated that predicted blood and brain ACN and CEO concentrations were similar in rats and humans exposed to ACN by inhalation. In contrast, rats consuming ACN in drinking water had higher predicted blood concentrations of ACN than humans exposed to the same concentration in water. Sensitivity and variability analyses were conducted on the model. While many parameters contributed to the estimated variability of the model predictions, the reaction rate of CEO with glutathione, hydrolysis rate for CEO, and blood:brain partition coefficient of CEO were the parameters predicted to make the greatest contributions to variability of blood and brain CEO concentrations in humans. The main contributor to predicted variance in human blood ACN concentrations in people exposed through drinking water was the Vmax for conversion of ACN to CEO. In contrast, the main contributors for variance in people exposed by inhalation were expected to be the rate of blood flow to the liver and alveolar ventilation rate, with the brain:blood partition coefficient also contributing to variability in predicted concentrations of ACN in the brain. Expected variability in blood CEO concentrations (peak or average) in humans exposed by inhalation or drinking water was modest, with a 95th-percentile individual expected to have blood concentrations 1.8-times higher than an average individual.
Publication
Journal: Journal of Food Science
March/17/2014
Abstract
This research evaluated the antimicrobial efficacy of pullulan films containing caraway essential oil (CEO). The films were prepared from a 10% of pullulan, containing from 0.12% to 10.0% of CEO. The composition of the CEO was analyzed with the use of gas chromatography. The antimicrobial activity of the CEO was evaluated with the method of serial microdilutions, and the films containing CEO-with the agar diffusion method against selected Gram-negative, Gram-positive bacteria, and fungi. The structure of the film surface and its cross-section were analyzed using a scanning electron microscope (SEM). Analyses were also carried out to determine the efficacy of a pullulan coating with 10% CEO on baby carrots experimentally inoculated with Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae, or Aspergillus niger and stored at a room temperature for 7 d. At a concentration of 0.12%, CEO inhibited the growth of all the tested microorganisms. Pullulan films containing 8% to 10% of CEO were active against all tested microorganisms. Populations of S. aureus on carrot samples were reduced by approximately 3 log CFU/g, while those of A. niger and S. cerevisiae by, respectively, 5 and 4 log CFU/g, after 7 d of storage. S. enteritidis was the most resistant among the tested species, since it was not significantly reduced after 7 d of storage. At the end of storage, samples treated with pullulan-caraway oil coating maintained better visual acceptability than control samples. Results of this study suggest the feasibility of applying a pullulan film with incorporated CEO to extend the microbiological stability of minimally processed foods.
Publication
Journal: Chemistry - A European Journal
August/24/2010
Abstract
Complete dehydrogenation of methane is studied on model Pt catalysts by means of state-of-the-art DFT methods and by a combination of supersonic molecular beams with high-resolution photoelectron spectroscopy. The DFT results predict that intermediate species like CH(3) and CH(2) are specially stabilized at sites located at particles edges and corners by an amount of 50-80 kJ mol(-1). This stabilization is caused by an enhanced activity of low-coordinated sites accompanied by their special flexibility to accommodate adsorbates. The kinetics of the complete dehydrogenation of methane is substantially modified according to the reaction energy profiles when switching from Pt(111) extended surfaces to Pt nanoparticles. The CH(3) and CH(2) formation steps are endothermic on Pt(111) but markedly exothermic on Pt(79). An important decrease of the reaction barriers is observed in the latter case with values of approximately 60 kJ mol(-1) for first C-H bond scission and 40 kJ mol(-1) for methyl decomposition. DFT predictions are experimentally confirmed by methane decomposition on Pt nanoparticles supported on an ordered CeO(2) film on Cu(111). It is shown that CH(3) generated on the Pt nanoparticles undergoes spontaneous dehydrogenation at 100 K. This is in sharp contrast to previous results on Pt single-crystal surfaces in which CH(3) was stable up to much higher temperatures. This result underlines the critical role of particle edge sites in methane activation and dehydrogenation.
Publication
Journal: Healthcare quarterly (Toronto, Ont.)
June/14/2011
Abstract
At a recent social policy conference - Recovering Together? Fiscal Pressures, Federalism and Social Policy, hosted by Queen's International Institute on Social Policy - there was much discussion of "healthcare's crowding out" of others of the determinants of health, education and income security being the predominant examples. I was struck by the loose language, four words/phrases in particular, used to describe reality - healthcare, system, single-payer and publicly funded. Physicians are increasingly moving beyond their already-demanding clinical roles to become chief executive officers (CEOs), chiefs of staff, clinical leaders, board members, deans and directors. Is this a good thing, and should physician leadership be encouraged? Or as Ron Liepert (2009, August), minister of Alberta Health and Wellness, asserts, are physicians better at diagnosing and treating people than running $8 billion organizations?
Publication
Journal: Water Science and Technology
May/7/2015
Abstract
Inorganic oxide nanoparticles (NPs) are used in semiconductor manufacturing operations such as wafer chemical-mechanical planarization (CMP). Understanding the stability of NPs in municipal wastewater is essential for the evaluation of the fate of NPs released to municipal wastewater treatment plants (WWTPs). This study aimed to evaluate the stability of Al(2)O(3), CeO(2), and SiO(2) NPs and CMP waste effluents containing these NPs in municipal wastewater. Al(2)O(3) and CeO(2) NPs were destabilized by wastewater constituents, as indicated by the formation of large agglomerates. However, the same NPs in the CMP waste slurries showed high stability in wastewater, probably due to additives present in the slurry that modify the surface chemistry of the particles. Likewise, both the commercial SiO(2) NPs and the CMP waste slurry containing SiO(2) NPs showed substantial stability in wastewater since this NP has a very low point of zero charge, which suggests that this NP could be the hardest one to remove in conventional WWTPs by aggregation-sedimentation. In summary, the results indicate that wastewater may destabilize NPs suspensions, which would facilitate NP removal in WWTPs. However, some chemicals present in real CMP slurries may counterbalance this effect. More research is needed to completely understand the surface chemistry involved.
Publication
Journal: Journal of the American Chemical Society
January/23/2006
Abstract
Ce-doped borosilicate (BSG), phosphosilicate (PSG), and borophosphosilicate (BPSG) glasses (B:P:Si molar ratios 8:0:92, 0:8:92, and 8:8:84; Ce:Si molar ratio 1 x 10(-)(4) to 1 x 10(-)(2)) were prepared by the sol-gel method. High-resolution transmission electron microscopy (HRTEM), (31)P, (29)Si, and (11)B magic angle spinning nuclear magnetic resonance (MAS NMR), electron paramagnetic resonance (EPR), and UV-vis absorption investigations demonstrated that, in PSG and BPSG, Ce(3+) ions interact with phosphoryl, [O=PO(3/2)], metaphosphate, [O=PO(2/ 2)O](-), and pyrophosphate, [O=PO(1/2)O(2)](2)(-), groups, linked to a silica network. This inhibits both CeO(2) segregation and oxidation of isolated Ce(3+) ions to Ce(4+), up to Ce:Si = 5 x 10(-)(3). In BSG, neither trigonal [BO(3/2)] nor tetrahedral [BO(4/2)](-) boron units coordinate cerium; thus, Ce(3+) oxidation occurs even at Ce:Si = 1 x 10(-)(4), as in pure silica glass (SG). The homogeneous rare-earth dispersion in the host matrix and the stabilization of the Ce(3+) oxidation state enhanced the intensity of the photoluminescence emission in PSG and BPSG with respect to BSG and SG. The energy of the Ce(3+) emission band in PSG and BPSG matrixes agrees with the phosphate environment of the rare earth.
Publication
Journal: Biosensors and Bioelectronics
April/25/2012
Abstract
Cerium oxide nanorods (CeO(2) NRs) were synthesized without templates through a low cost and simple non-isothermal precipitation method. The structure and morphology of CeO(2) NRs were characterized by X-ray diffraction and transmission electron microscopy. The CeO(2) NRs films, deposited on indium tin oxide (ITO)-coated glass substrates through electrophoretic deposition, were used for the immobilization of glucose oxidase (GOx). Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy were used to characterize the CeO(2) NRs/ITO and GOx/CeO(2) NRs/ITO electrodes. The GOx/CeO(2) NRs/ITO electrode exhibits a linear range for the detection of glucose from 2 to 26 mM (correlation coefficient: 0.99) at 1-2s response time. Biosensor sensitivity is 0.165 μA mM(-1) cm(-2) with 100 μM detection limit. The anti-interference ability of the biosensor was also examined. The mediator-less application of CeO(2) NRs for glucose sensing was demonstrated.
Publication
Journal: Journal of Mass Spectrometry
October/24/2010
Abstract
The interactions between coumarins and the surface of fumed SiO(2), CeO(2)/SiO(2), TiO(2)/SiO(2) and Al(2)O(3)/SiO(2) were assessed by means of temperature-programmed desorption mass spectrometry. The different stages of the thermolysis of coumarin were identified and an analysis of the underlying reactions was performed. The kinetic parameters of the involved reactions were thus obtained. The decomposition of thiazolyl-substituted coumarins was found to proceed through a 'thiazole-thiazine' ring expansion in the adsorbed state. A linear correlation between the sigma constants (Sigma sigma) of the coumarin substituents and the activation energy of CO(2) formation was obtained.
Publication
Journal: Journal of Colloid and Interface Science
May/8/2007
Abstract
Electrospinning was employed to fabricate polymer-ceramic composite fibers from solutions containing poly(vinyl pyrrolidone) (PVP), Ce(NO(3))(3) x 6H(2)O and ZrOCl(2) x 8H(2)O. Upon firing the composite fibers at 1000 degrees C, Ce(0.67)Zr(0.33)O(2) fibers with diameters ranging from 0.4 to 2 microm were synthesized. These fibers exhibit strong resistance to sintering. They still have specific surface area around 11.8 m(2)/g after being heated at 1000 degrees C for 6 h.
Publication
Journal: Nature Communications
February/23/2019
Abstract
Replacement of Hg with non-toxic Au based catalysts for industrial hydrochlorination of acetylene to vinyl chloride is urgently required. However Au catalysts suffer from progressive deactivation caused by auto-reduction of Au(I) and Au(III) active sites and irreversible aggregation of Au(0) inactive sites. Here we show from synchrotron X-ray absorption, STEM imaging and DFT modelling that the availability of ceria(110) surface renders Au(0)/Au(I) as active pairs. Thus, Au(0) is directly involved in the catalysis. Owing to the strong mediating properties of Ce(IV)/Ce(III) with one electron complementary redox coupling reactions, the ceria promotion to Au catalysts gives enhanced activity and stability. Total pre-reduction of Au species to inactive Au nanoparticles of Au/CeO2&AC when placed in a C2H2/HCl stream can also rapidly rejuvenate. This is dramatically achieved by re-dispersing the Au particles to Au(0) atoms and oxidising to Au(I) entities, whereas Au/AC does not recover from the deactivation.
Publication
Journal: Avian Diseases
April/13/2015
Abstract
In October of 2005 an outbreak of a vaccine-like strain of infectious laryngotracheitis (ILT), indistinguishable from the chicken embryo origin (CEO)-like vaccine strains, was detected by routine passive surveillance in the Central Valley of California, U. S. A. In response, a highly coordinated industry effort by two companies led to a significant decrease in the incidence of ILT over the same geographic region between 2008-2012. In order to understand the geographic and temporal spread of ILT in California before and after the outbreak, Global Information Systems (GIS) mapping coupled with spatial, temporal, and spatial- temporal statistics were used to identify retrospective and prospective low-rate clustering (i.e., less ILT than statistically expected) and high-rate clustering (i.e., more ILT than statistically expected) of ILT spatially and temporally. Results showed two high-rate retrospective spatial-temporal clusters and one low-rate prospective spatial-temporal cluster which were all statistically significant (P < 0.05). Overall, spatial-temporal clustering accounted for 36.9% of the positive ILT cases, while temporal clustering and spatial clustering done separately each accounted for 0% of the ILT cases, respectively. This demonstrates the utility of combining spatial and temporal clustering for ILT surveillance. Due to the risk of reversion to virulence and spread to immunologically naive broilers, future application of the CEO-based vaccine in the identified high rate spatial-temporal clusters should be avoided and other vaccine alternatives considered in order to avoid repeat outbreaks in those areas. This should especially be followed during the winter months of December, January, and February, which were found to have the highest prevalence of ILT (P < 0.05). Analysis of GIS data within the high-rate clusters showed that wind direction and farm density were minor factors in the spread of ILT. Shared roads may have played a role in the spread of ILT in one of the two high rate spatial-temporal clusters.
Publication
Journal: Surveys in Geophysics
August/9/2019
Abstract
Several upcoming satellite missions have core science requirements to produce data for accurate forest aboveground biomass mapping. Largely because of these mission datasets, the number of available biomass products is expected to greatly increase over the coming decade. Despite the recognized importance of biomass mapping for a wide range of science, policy and management applications, there remains no community accepted standard for satellite-based biomass map validation. The Committee on Earth Observing Satellites (CEOS) is developing a protocol to fill this need in advance of the next generation of biomass-relevant satellites, and this paper presents a review of biomass validation practices from a CEOS perspective. We outline the wide range of anticipated user requirements for product accuracy assessment and provide recommendations for the validation of biomass products. These recommendations include the collection of new, high-quality in situ data and the use of airborne lidar biomass maps as tools toward transparent multi-resolution validation. Adoption of community-vetted validation standards and practices will facilitate the uptake of the next generation of biomass products.
Publication
Journal: Journal of Hazardous Materials
October/27/2010
Abstract
A BaMnCe ternary catalyst was prepared by impregnating barium acetate on MnO(x)-CeO(2) mixed oxides, with the monoxide supported catalysts and the solid solution support as references. The activities of the catalysts for soot oxidation were evaluated in the presence of NO under an energy transference controlled regime. BaMnCe presented the lowest maximal soot oxidation rate temperature at 393 degrees C among the catalysts investigated. Although BaMnCe experienced a loss in the specific surface area and low-temperature redox property due to blocking of the support pores by barium carbonate, its superior soot oxidation activity highlighted the importance of relatively stable bidentate/monodentate nitrates coordinated to Mn(x+) and Ce(x+) sites and more stable ionic barium nitrate. About half of the nitrates stored on this catalyst decomposed within the temperature interval of 350-450 degrees C, and the ignition temperature of soot decreased significantly with involvement of the nitrates or NO(2) released.
Publication
Journal: Materials
November/13/2018
Abstract
TiO₂-ZrO₂ (Ti-Zr) carrier was prepared by a co-precipitation method and 1 wt. % V₂O₅ and 0.2 CeO₂ (the Mole ratio of Ce to Ti-Zr) was impregnated to obtain the V₂O₅-CeO₂/TiO₂-ZrO₂ catalyst for the selective catalytic reduction of NOx by NH₃. The transient activity tests and the in situ DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) analyses were employed to explore the NH₃-SCR (selective catalytic reduction) mechanism systematically, and by designing various conditions of single or mixing feeding gas and pre-treatment ways, a possible pathway of NOx reduction was proposed. It was found that NH₃ exhibited a competitive advantage over NO in its adsorption on the catalyst surface, and could form an active intermediate substance of -NH₂. More acid sites and intermediate reaction species (-NH₂), at lower temperatures, significantly promoted the SCR activity of the V₂O₅-0.2CeO₂/TiO₂-ZrO₂ catalyst. The presence of O₂ could promote the conversion of NO to NO₂, while NO₂ was easier to reduce. The co-existence of NH₃ and O₂ resulted in the NH₃ adsorption strength being lower, as compared to tests without O₂, since O₂ could occupy a part of the active site. Due to CeOCeO₂/TiO₂-ZrO₂ catalyst. If NOx were to be pre-adsorbed in the catalyst, the formation of nitrate and nitro species would be difficult to desorb, which would greatly hinder the SCR reaction. All the findings concluded that NH₃-SCR worked mainly through the Eley-Rideal (E-R) mechanism.
Publication
Journal: Chemical Communications
October/3/2005
Abstract
Electrochemical oxidation of methanol, ethanol, glycerol and ethylene glycol (EG) on novel Pt-CeO(2)/C catalysts in alkaline media has been studied and shows an improved performance in terms of the electrode activity and the poisoning resistance.
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