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Publication
Journal: Journal of the American Chemical Society
May/3/2010
Abstract
The catalytic properties of Au/CeO(2) systems are sensitive to the nature of Au clusters; however, atomic information on Au clusters is sparse. In this work, we use density functional theory to investigate the nucleation of small Au clusters (up to Au(11)). By depositing Au atoms one by one at a reduced CeO(2){111} surface, we present detailed nucleation patterns. Although relatively small in size, the nanoclusters obtained exhibit interesting characteristic features. In addition to the face-centered cubic (fcc) geometry, reminiscent of bulk Au, we also find the existence of novel hexagonal close-packed (hcp) structures. Furthermore, the facets of the nanoclusters are versatile, comprising {111}/{100} combinations for the fcc-like clusters and {10(1)1}/{0001} combinations for the hcp-like. Electronically, the contact layer Au atoms that bond with surface O atoms are positively charged, which could have significant implications in catalysis.
Publication
Journal: Journal of Chemical Physics
January/8/2009
Abstract
Within the framework of the GGA+U implementation of density functional theory, we investigate atomistic and electronic structures of Au adsorbed on the stoichiometric and the defective CeO(2){111} surfaces, in the latter of which either O or Ce vacancies are presented. We show that on the stoichiometric surface, the most stable adsorption site of Au is not on the top of the outermost O atoms, as previously suggested, but on a bridgelike site in which the Au directly binds to two O atoms. We suggest that on both sites, the original empty Ce 4f states near the Fermi level facilitate the oxidation of the Au; the preference of the Au for being on the bridgelike site is due to the larger O 2p-d(Au) mixing, accompanied by more significant electron redistributions. On the reduced surface with O vacancies, the most stable adsorption site of Au is near the vacancy position. Unlike that on the stoichiometric surface, strong ionic bonding character exists between Au and Ce, as the former becomes Au(delta-) due to the occupation of the 6s(Au) orbitals. Upon substitution for one of the Ce atoms in the lattice, the Au possesses a much stronger positive charge than that in other cases. We find that although Au is strongly bonded when it is at the Ce vacancy site, the overall binding (i.e., with the Ce vacancy formation energy being taken into account) is weaker than that for Au adsorbed at the stoichiometric surface.
Publication
Journal: ChemPhysChem
July/11/2007
Abstract
Interactions between O(2) and <em>CeO</em>(2) are examined experimentally using in situ Raman spectroscopy and theoretically using density-functional slab-model calculations. Two distinct oxygen bands appear at 825 and 1131 cm(-1), corresponding to peroxo- and superoxo-like species, respectively, when partially reduced <em>CeO</em>(2) is exposed to 10 % O(2). Periodic density-functional theory (DFT) calculations aid the interpretation of spectroscopic observations and provide energetic and geometric information for the dioxygen species adsorbed on <em>CeO</em>(2). The O(2) adsorption energies on unreduced <em>CeO</em>(2) surfaces are endothermic (0.91<DeltaE(ads)<0.98 eV), while those on reduced surfaces are exothermic (-4. 0<DeltaE(ads)<-0.9 eV), depending on other relevant surface processes such as chemisorption and diffusion into the bulk. Partial reduction of surface Ce(4+) to Ce(3+) (together with formation of oxygen vacancies) alters geometrical parameters and, accordingly, leads to a shift in the vibrational frequencies of adsorbed oxygen species compared to those on unreduced <em>CeO</em>(2). Moreover, the location of oxygen vacancies affects the formation and subsequent dissociation of oxygen species on the surfaces. DFT predictions of the energetics support the experimental observation that the reduced surfaces are energetically more favorable than the unreduced surfaces for oxygen adsorption and reduction.
Publication
Journal: Physical Review Letters
May/11/2015
Abstract
We examine the effect of mechanical strain on the migration of oxygen vacancies in fluorite-structured ceria by means of density functional theory calculations. Different strain states (uniaxial, biaxial and isotropic) and strain magnitudes (up to ± 7%) are considered. From the calculations we extract the complete activation volume tensor for oxygen-vacancy migration in CeO(2), that is, all diagonal ΔV(mig,kk) and off-diagonal ΔV(mig,kl) tensor elements. These individual tensor elements are found, crucially, to be independent of strain state; they do, however, depend on stress (ΔV(mig,kk)) or effective pressure (ΔV(mig,kl)). Armed with knowledge of all tensor elements we predict strain states for which oxygen-ion transport in ceria is maximized. In general, with our approach the effect of an arbitrary strain state on the migration barrier for mass transport in a solid can be calculated quantitatively.
Publication
Journal: Physical Review Letters
May/20/2015
Abstract
Surface and subsurface oxygen vacancies on the slightly reduced CeO(2)(111) surface have been studied by atomic resolution dynamic force microscopy at 80 K. Both types of defect are clearly identified by the comparison of the observed topographic features with the corresponding structures predicted from recent first-principles calculations. By combining two simultaneously acquired signals (the topography and the energy dissipated from the cantilever oscillation), we are able to unambiguously locate subsurface oxygen vacancies buried at the third surface atomic layer. We report evidence of local ordering of these subsurface defects that suggests the existence of a delicate balance between subtle interactions among adjacent subsurface oxygen vacancy structures.
Publication
Journal: Journal of Physics Condensed Matter
August/15/2012
Abstract
Water molecules adsorbed on the CeO(2)(111) surface are investigated by non-contact atomic force microscopy (NC-AFM) at several tip-sample temperatures ranging between 10 and 300 K. Depending on the strength of the tip-surface interaction, they appear as triangular protrusions extended over three surface oxygen atoms or as small pits at hollow sites. During NC-AFM imaging with the tip being close to the surface, occasionally the transfer of molecules between tip and surface or the tip-induced lateral displacement of water molecules to equivalent surface lattice sites is observed. We report how this situation can be exploited to produce controlled lateral manipulations. A protocol to manipulate the water molecules between pre-defined neighbouring equivalent adsorption sites of the regular lattice as well as across a surface oxygen vacancy is demonstrated.
Publication
Journal: Journal of Photochemistry and Photobiology B: Biology
April/25/2017
Abstract
<em>CeO</em>2/CdO multi-layered nanoplatelet arrays have been synthesized by sol-gel method at two different temperatures using Citrus limonum fruit extract and the effect of particle size on the photocatalytic performance is studied. The particle size and phases was analysed by X-ray diffraction pattern (XRD) which brought out the formation of cubic phase in the synthesized samples. Field Emission Scanning electron microscopy (FESEM) revealed the surface morphology and made up of cumulative form of platelet shaped arrays with an average size of 10nm. The elemental composition and the purity of the nanomaterials were confirmed by Energy Dispersive X-ray spectroscopy (EDX). <em>CeO</em>2/CdO multilayered binary metal oxide nanoplatelet arrays were formed which was further explored with Fourier transform infrared spectroscopy (FTIR), it reveals that the nanocomposites contain <em>CeO</em> and CdO bonds. Determination of the direct and indirect bandgap energy of the nanoplatelet arrays was carried out by UV-Vis-DRS studies. In MG degradation, both the hole (h+) and hydroxyl radical (OH) played a major role than the superoxide radical (O2-). Possible photo degradation mechanisms are proposed and discussed in this article. <em>CeO</em>2/CdO multi-layered nanoplatelet arrays showed antibacterial activity and among the tested ones, it showed better growth inhibition towards P. aeruginosa MTCC73. Thus, this greener synthetic procedure was a highly effective method due to low-cost, highly effective UV light responsive material for environmental safety.
Publication
Journal: Harvard Business Review
August/5/1996
Abstract
Henry Mintzberg, a professor of management at McGill University in Canada and at INSEAD in France, takes aim at the hype surrounding management fads and gurus and dares to suggest that the emperor has no clothes. In order to rile all who care about management and get them thinking creatively, he presents ten contrarian observations on such topics as the meanness of leanness, the folly of CEOs who fancy themselves strategists, the disempowering that so-called empowerment creates, the myopia of purely financial measures, and the inadequacy of M.B.A. programs. Mintzberg maintains, for example, that it is time to delayer the delayerers. He argues that delayering has created more problems than it has solved be cause it is, in essence, a process by which people who barely know what's going on get rid of those who do--a process ensuring that the real database of the organization, the key to what was its future, lines up at the unemployment office. Too many managers, he says, dream of becoming the next turnaround doctor. They fail to understand that great organizations, once created, don't need great leaders: if a company can't function on its own, a hero won't help. A leader who draws out the knowledge embedded in all parts of an organization is a leader who can help a company function alone--without heroes. Such leaders often practice what Mintzberg calls the craft style of management (as opposed to the professional style or the boss style). It is about inspiring, not empowering. It is based on mutual respect rooted in common experience and offers hope for improving what is now wrong with management.
Publication
Journal: ChemSusChem
May/8/2012
Abstract
A method, based on self assembly, for preparing core-shell nanostructures that are dispersible in organic solvents is demonstrated for Pd and Pt cores with CeO(2), TiO(2), and ZrO(2) shells. Transmission electron microscopy (TEM) of these nanostructures confirmed the formation of distinct metal cores, approximately 2 nm in diameter, surrounded by amorphous oxide shells. Functional catalysts were prepared by dispersing the nanostructures onto an Al(2)O(3) support; and vibrational spectra of adsorbed CO, together with adsorption uptakes, were used to demonstrate the accessibility of the metal core to CO and the porous nature of the oxide shell. Measurements of water-gas-shift (WGS) rates demonstrated that these catalysts exhibit activities similar to that of conventional supported catalysts despite having lower metal dispersions. Pd-based CeO(2) and TiO(2) core-shell catalysts exhibit significant transient deactivation, which is probably caused by a decrease in the exposed metal surface area due to the ease of reduction of the shells. Alternatively, Pt-based analogous core-shell catalysts do not exhibit such a transient decrease. Both Pd- and Pt-based ZrO(2) core-shell catalysts deactivate at a significantly lower rate due to the less reducible nature of the ZrO(2) shell.
Publication
Journal: Nanoscale
October/27/2010
Abstract
Selected metal oxide nanoparticles are capable of strongly adsorbing large amounts of halogens (Cl(2), Br, I(2)) and mixed halogens. These solid adducts are relatively stable thermally, and they can be stored for long periods. However, in the open environment, they are potent biocides. Herein are described studies with a number of bacteriophage MS2, phiX174, and PRD-1 (virus examples). PRD-1 is generally more resistant to chemical disinfection, but in this paper it is shown to be very susceptible to selected interhalogen and iodine adducts of CeO(2), Al(2)O(3), and TiO(2) nanoparticles. Overall, the halogen adducts of TiO(2) and Al(2)O(3) were most effective. The mechanism of disinfection by these nanoparticles is not completely clear, but could include abrasive properties, as well as oxidative powers. A hypothesis that nanoparticles damage virons or stick to them and prevent binding to the host cell is a consideration that needs to be explored. Herein are reported comparative biocidal activities of a series of adducts and electron microscope images of before and after treatment.
Publication
Journal: Journal of Food Science
June/5/2018
Abstract
Cinnamon leaf and bark essential oils have long been used as natural preservatives and flavoring agents in foods. This study determined antimicrobial effects of leaf and bark of cinnamon essential oils (CEOs) against 2 foodborne pathogens, Salmonella Typhimurium (S.T.) and Listeria monocytogenes (L.m.), at 2 initial bacterial levels (4- and 9-log CFU/mL) in strawberry shakes. The antimicrobial study of CEOs at 0.1% and 0.5% in strawberry shakes against S.T. and L.M. showed a significant difference (P < 0.05) in log reductions of both bacterial growth at low (4-log CFU/mL) and high (9-log CFU/mL) initial bacterial levels. Addition of 0.5% CEOs into strawberry shakes at 4 °C completely inhibited both bacteria after a period of 8 d storage. Shelf-life study showed that acidity and total solid content were not affected during storage. The strawberry shakes containing bark CEO had higher ratings of sensory acceptability compared to leaf CEO, with or without the addition of 1% masking agent. In conclusion, this study demonstrated that CEO derived from bark was better than that from leaf in terms of their antimicrobial activity and sensory aspect.
UNASSIGNED
This study demonstrates that essential oils derived from cinnamon bark and leaf have the potential to be used as natural antimicrobial ingredient in milk beverages with respect to sensory aspect. This finding promotes the acceptance of natural antimicrobials among consumers, while providing enhanced safer products to the food industry application.
Publication
Journal: Harvard Business Review
February/3/2015
Abstract
Few companies measure whether the design of their workspaces helps or hurts performance, but they should. The authors have collected data that capture individuals' interactions, communications, and location information. They've learned that face-to-face interactions are by far the most important activity in an office; creating chance encounters between knowledge workers, both inside and outside the organization, improves performance. The Norwegian telecom company Telenor was ahead of its time in 2003, when it incorporated "hot desking" (no assigned seats) and spaces that could easily be reconfigured for different tasks and evolving teams. The CEO credits the design of the offices with helping Telenor shift from a state-run monopoly to a competitive multinational carrier with 150 million subscribers. In another example, data collected at one pharmaceuticals company showed that when a salesperson increased interactions with coworkers on other teams by 10%, his or her sales increased by 10%. To get the sales staff running into colleagues from other departments, management shifted from one coffee machine for every six employees to one for every 120 and created a new large cafeteria for everyone. Sales rose by 20%, or $200 million, afterjust one quarter, quickly justifying the capital investment in the redesign.
Publication
Journal: Journal of Ethnopharmacology
April/20/2014
Abstract
UNASSIGNED
Lippia alba (Mill.) N. E. Brown (Verbenaceae) is an aromatic species used in Central and South America as eupeptic for indigestion. In Argentina, it is used by the "criollos" from the Chaco province. There are several chemotypes which differ in the chemical composition of the essential oils. Nowadays, it is experimentally cultivated in some countries of the region, including Argentina.
OBJECTIVE
To compare the chemical composition and pharmacology of the essential oils from two chemotypes: "citral" (CEO) and "linalool" (LEO), in isolated rat duodenum and ileum.
METHODS
Contractile concentration-response curves (CRC) of acetylcholine (ACh) and calcium in 40mM K(+)-medium (Ca(2+)-CRC) were done in isolated intestine portions, in the absence and presence of CEO or LEO at different concentrations.
RESULTS
Likewise verapamil, CEO and LEO induced a non-competitive inhibition of the ACh-CRC, with IC50 of 7.0±0.3mg CEO/mL and 37.2±4.2mg LEO/mL. l-NAME, a NO-synthase blocker, increased the IC50 of CEO to 26.1±8.7mg CEO/mL. Likewise verapamil, CEO and LEO non-competitively inhibited the Ca(2+)-CRC, with IC50 of 6.3±1.7mg CEO/mL, 7.0±2.5mg LEO/mL and 0.24±0.04mg verapamil/mL (pIC50: 6.28). CEO was proved to possess limonene, neral, geranial and (-)-carvone as the major components, while LEO was rich in linalool.
CONCLUSIONS
Results suggest that CEO has five times more potency than LEO to inhibit muscarinic contractions. The essential oils of both chemotypes interfered with the Ca(2+)-influx, but with an IC50 about 28 times higher than that of verapamil. Moreover, CEO partially stimulated the NO production. These results show the medicinal usefulness of both Lippia alba chemotypes, thus validating its traditional use, potency and mechanism of action.
Publication
Journal: PLoS ONE
August/20/2017
Abstract
BACKGROUND
Early onset sepsis (EOS) is a major cause of morbidity and mortality in preterm infants, yet diagnosis remains inadequate resulting in missed cases or prolonged empiric antibiotics with adverse consequences. Evaluation of acute phase reactant (APR) biomarkers in umbilical cord blood at birth may improve EOS detection in preterm infants with intrauterine infection.
METHODS
In this nested case-control study, infants (29.7 weeks gestation, IQR: 27.7-32.2) were identified from a longitudinal cohort with archived cord blood and placental histopathology. Patients were categorized using culture, laboratory, clinical, and antibiotic treatment data into sepsis groups: confirmed sepsis (cEOS, n = 12); presumed sepsis (PS, n = 30); and no sepsis (controls, n = 30). Nine APRs were measured in duplicate from cord blood using commercially available multiplex immunoassays (Bio-Plex Pro™). In addition, placental histopathologic data were linked to biomarker results.
RESULTS
cEOS organisms were Escherichia coli, Streptococcus agalactiae, Proteus mirabilis, Haemophilus influenzae and Listeria monocytogenes. C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin (Hp), serum amyloid P and ferritin were significantly elevated in cEOS compared to controls (p<0.01). SAA, CRP, and Hp were elevated in cEOS but not in PS (p<0.01) and had AUCs of 99%, 96%, and 95% respectively in predicting cEOS. Regression analysis revealed robust associations of SAA, CRP, and Hp with EOS after adjustment for covariates. Procalcitonin, fibrinogen, α-2-macroglobulin and tissue plasminogen activator were not significantly different across groups. Placental acute inflammation was associated with APR elevation and was present in all cEOS, 9 PS, and 17 control infants.
CONCLUSIONS
This study shows that certain APRs are elevated in cord blood of premature infants with EOS of intrauterine origin. SAA, CRP, and Hp at birth have potential diagnostic utility for risk stratification and identification of infants with EOS.
Publication
Journal: Nanotoxicology
May/29/2012
Abstract
Six TiO₂ and two CeO₂ nanomaterials with dry sizes ranging from 6-410 nm were tested for their ability to cause DNA centered free radicals in vitro in the concentration range of 10-3,000 ug/ml. All eight of the nanomaterials significantly increased the adduction of the spin trap agent 5,5-dimethyl-1-pyroline N-oxide (DMPO) to DNA as measured by the experimental technique of immuno-spin trapping. The eight nanomaterials differed considerably in their potency, slope, and active concentration. The largest increase in DNA nitrone adducts was caused by a TiO₂ nanomaterial (25 nm, anatase) from Alfa Aesar. Some nanomaterials that increased the amount of DNA nitrone adducts at the lowest exposure concentrations (100 ug/ml) were Degussa TiO₂ (31 nm), Alfa Aesar TiO₂ (25 nm, anatase) and Nanoamor CeO₂ (8 nm, cerianite). At exposure concentrations of 10 or 30 ug/ml, no nanomaterials showed significant in vitro formation of DNA nitrone adducts.
Publication
Journal: Materials
November/12/2018
Abstract
Al-TiC-CeO₂ composite coatings have been prepared by using a laser cladding technique, and the microstructure and properties of the resulting composite coatings have been investigated using scanning electron microscopy (SEM), a 3D microscope system, X-ray diffraction (XRD), micro-hardness testing, X-ray stress measurements, friction and wear testing, and an electrochemical workstation. The results showed that an Al-Fe phase appears in the coatings under different applied laser powers and shows good metallurgical bonding with the matrix. The dilution rate of the coating first decreases and then increases with increasing laser power. The coating was transformed from massive and short rod-like structures into a fine granular structure, and the effect of fine grain strengthening is significant. The microhardness of the coatings first decreases and then increases with increasing laser power, and the maximum microhardness can reach 964.3 HV0.2. In addition, the residual stress of the coating surface was tensile stress, and crack size increases with increasing stress. When the laser power was 1.6 kW, the coating showed high corrosion resistance.
Publication
Journal: Chemico-Biological Interactions
December/3/2001
Abstract
(1-Chloroethenyl)oxirane (CEO) is a metabolite of beta-chloroprene (2-chloro-1,3-butadiene, CD). The purpose of this study was to evaluate the in vitro mutagenic and clastogenic (chromosome breaking) potential of CEO. For comparative purposes, the study also included an evaluation of the racemic compounds, 3,4-epoxy-1-butene (EB) and 1,2:3,4-diepoxybutane (DEB). Mutagenicity was evaluated in a bacterial reverse mutation test (Ames), using the pre-incubation method in the presence and absence of an exogenous metabolism system (Aroclor)-induced rat liver S9). Four Salmonella typhimurium tester strains, TA97a, TA98, TA100 and TA1535 were used. The exposure concentrations in the sealed incubation vials ranged from 0 to 69 mM for CEO, 0 to 102 mM for EB, and 0 to 83 mM for DEB. All three compounds showed signs of toxicity, with DEB being substantially more toxic than either CEO or EB. Mutagenic activity was observed with all three chemicals in primarily the base pair substitution strains (S. typhimurium TA100 and TA1535), but some activity was also seen in the frameshift elimination strains (S. typhimurium TA97a and TA98). The observed mutagenic responses after exposure with CEO or EB were greater than the observed response for DEB, most likely because of the higher toxicity of DEB. Generally, the mutagenic responses were unchanged in the frameshift strains and base pair substitution strains in the presence of S9 metabolism. In vitro clastogenicity was evaluated using the cytochalasin-B blocked micronucleus test in cultured Chinese hamster V79 cells. The test was conducted without S9 metabolism because of the absence of substantial changes in the Ames test. Exposure concentrations ranged from 0 to 0.943 mM for CEO, 0 to 3.0 mM for EB, and 0 to 0.035 mM for DEB, with the upper exposure concentrations dictated by cytotoxicity. Cytotoxicity, measured as a reduction in the proportion of binucleated cells and altered cell morphology, was observed for CEO at concentrations>> or =0.175 mM. Exposure to EB led to a reduced proportion of binucleated cells at concentrations>> or =2.0 mM, and cell death was observed after DEB exposure at concentrations>> or =0.025 mM. No clastogenicity was observed in the V79 cells when tested up to cytotoxic concentrations of CEO, whereas an elevated frequency of micronuclei was observed after exposure to either EB >> or =1.0 mM) or DEB >> or =0.0125 mM). These results suggest that CEO-induced mutagenicity, but not clastogenicity, may contribute to the observed beta-chloroprene-induced carcinogenicity in the rodent bioassay studies.
Publication
Journal: Journal of Rural Health
March/17/2005
Abstract
BACKGROUND
Critical access hospitals (CAHs) are a federal Medicare category for isolated rural facilities with 15 or fewer acute care beds that receive cost-based reimbursement from Medicare.
OBJECTIVE
This study examines the role of foreign-born international medical graduates (IMGs) in the staffing of CAHs.
METHODS
Chief executive officers (CEOs) of CAH facilities answered a telephone survey on their use of IMGs and the characteristics of those IMGs in winter 2002 (388 responded, for a 96% response rate). This descriptive report presents roles and characteristics of IMGs in CAH facilities and the opinions of the CEOs about these practitioners.
RESULTS
Overall, 1 (24%) in 4 admitting physicians in CAHs are graduates of non-US medical schools (compared with 23% of physicians nationally), although the rates are higher for CAHs in persistent poverty counties, CAHs that report recruitment problems, and CAHs with smaller medical staffs. Hospitals east of the Mississippi River are more heavily reliant on IMGs than hospitals in the west. Most IMGs are internists (59%) and most (61%) come from India, the Philippines, or Pakistan. Hospital administrators rate the clinical skills of their IMGs highly and their interpersonal skills only slightly lower. Almost half of CAH administrators said their communities recruited their first IMGs during or after 1994, the year of pro-IMG legislative changes.
CONCLUSIONS
IMG physicians play a significant and possibly growing role in staffing CAHs.
Publication
Journal: Analytica Chimica Acta
January/31/2012
Abstract
The capability of ICP-MS equipped with the high matrix introduction system (HMI) for accurate analysis of lanthanoids in environmental samples was investigated. Compared to the conventional operation, the amounts of oxide and hydroxide molecular species formed in the plasma were reduced by up to 5 times. The relative yields of oxides did not exceed 0.02% for BaO(+) species and were as low as 0.3% for lanthanoids with the highest oxide-formation rates (LaO(+), CeO(+), PrO(+) and NdO(+)). Hydroxide formation was less than 0.02% when HMI system was used. In addition, two digestion procedures were evaluated by the analysis of standard reference materials (SRMs) of different matrices. The digestion efficiency and limits of detection (LOD) were improved when samples were digested with a mixture of HNO(3)/H(2)O(2)/HCl/HF, and HF was removed by evaporation in presence of concentrated HCl. Using this procedure and HMI-ICP-MS analysis, LOD ranged from 0.1 μg kg(-1) to 6 μg kg(-1). Recoveries ranged from 85 to 115% for La to Ho and from 75 to 85% for the other lanthanoids. Relative standard deviations for replicate analysis of SRMs were less than 10%.
Publication
Journal: Human Reproduction
March/29/1995
Abstract
A single s.c. injection of 1000 IU of pregnant mare's serum gonadotrophin (PMSG) stimulates the growth of multiple antral follicles in cynomolgus monkeys (Macaca fascicularis). The number of cumulus-enclosed oocytes (CEO) from six non-stimulated controls was 36 (mean = 6). In contrast, a total of 95 CEO (mean = 31.7) were recovered from three animals stimulated and ovariectomized 3 days later, while 385 CEO (mean = 128.3) were obtained from three animals stimulated and ovariectomized 4 days later. A comparison of the effects of highly purified human follicle-stimulating hormone (FSH), human luteinizing hormone (LH) and human thyroid-stimulating hormone (TSH) on cultures of rhesus monkey (Macaca mulatta) CEO cultured in medium 199 for 48 h showed that FSH and LH stimulated cumulus expansion but had moderate effects on the progression of meiosis. The progression that did occur seldom proceeded beyond the metaphase I stage. Human TSH had no demonstrable effect on cumulus expansion and meiotic progression. In other experiments FSH, LH and oestradiol-17 beta were added jointly to medium CMRL 1066 in which CEO from non-PMSG-stimulated and PMSG-stimulated cynomolgus monkeys were cultured for 48 h. If the CEO were obtained from non-PMSG-stimulated monkeys the hormones caused a significant cumulus expansion, but had only a limited effect on meiotic progression. However, if the CEO were obtained from PMSG-stimulated monkeys there was a significant stimulation of cumulus expansion and meiotic progression. The hormone treatment resulted in a yield of 72.8% metaphase II oocytes compared with 40.9% in the controls.
Publication
Journal: ChemPhysChem
May/31/2007
Abstract
Reaction mechanisms for the interactions between CeO(2)(111) and (110) surfaces are investigated using periodic density functional theory (DFT) calculations. Both standard DFT and DFT+U calculations to examine the effect of the localization of Ce 4f states on the redox chemistry of H(2)-CeO(2) interactions are described. For mechanistic studies, molecular and dissociative local minima are initially located by placing an H(2) molecule at various active sites of the CeO(2) surfaces. The binding energies of physisorbed species optimized using the DFT and DFT+U methods are very weak. The dissociative adsorption reactions producing hydroxylated surfaces are all exothermic; exothermicities at the DFT level range from 4.1 kcal mol(-1) for the (111) to 26.5 kcal mol(-1) for the (110) surface, while those at the DFT+U level are between 65.0 kcal mol(-1) for the (111) and 81.8 kcal mol(-1) for the (110) surface. Predicted vibrational frequencies of adsorbed OH and H(2)O species on the surfaces are in line with available experimental and theoretical results. Potential energy profiles are constructed by connecting molecularly adsorbed and dissociatively adsorbed intermediates on each CeO(2) surface with tight transition states using the nudged elastic band (NEB) method. It is found that the U correction method plays a significant role in energetics, especially for the intermediates of the exit channels and products that are partially reduced. The surface reduction reaction on CeO(2)(110) is energetically much more favorable. Accordingly, oxygen vacancies are more easily formed on the (110) surface than on the (111) surface.
Publication
Journal: Milbank Quarterly
July/25/2001
Abstract
Hospital governance arrangements affect institutional policymaking and strategic decisions and can vary by such organizational attributes as ownership type/control, size, and system membership. A comparison of two national surveys shows how hospital governing boards changed in response to organizational and environmental pressures between 1989 and 1997. The magnitude and direction of changes in (1) board structure, composition, and selection; (2) CEO-board relations; and (3) board activity, evaluation, and compensation are examined for the population of hospitals and for different categories of hospitals. The findings suggest that hospital boards are engaging in selective rather than wholesale change to meet the simultaneous demands of a competitive market and traditional institutional orientations to community, the disenfranchised, and philanthropic service. Results also suggest parallel increases in collaboration between boards and CEOs and in board scrutiny of CEOs.
Publication
Journal: Profiles in healthcare communications
May/9/2007
Abstract
Four years ago, Nick Jacobs didn't know what the term "blogging" meant. As the president and CEO of the Windber (PA) Research Institute and the Windber Medical Center, that's not surprising. But this not-so-typical hospital president changed all that by launching his own blog three years ago and putting his small, 82-bed facility on the map.
Publication
Journal: Frontiers of Health Services Management
November/27/2006
Abstract
By the time I walked into the conference call at about 7 a.m. on Tuesday, August 30, HCA's Tulane hospital was surrounded by between four and six feet of water, depending on the side of the building. The water was slowly rising. An estimated 1,300 people were trapped at Tulane Hospital. No CEO has ever had as much reason to be proud of his company as I did during the next few days. We safely evacuated Tulane's patients, staff members, and family members, coordinating more than 200 helicopter sorties to and from Tulane in the process. We transferred every patient to a waiting hospital and took nearly every staff and family member to an HCA-run shelter in Lafayette, Louisiana, where they were bathed, fed, inoculated, given shelter, given access to prepaid cellular phones, and sent where they needed to go. This, I believe, was one of HCA's greatest hours, but we also learned many lessons from the catastrophic event. Although we hope and pray that nothing like this ever happens again, the things we learned can be of use to the healthcare community at large.
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