215 research outputs found

    Influence of the strong metal support interaction effect (SMSI) of Pt/TiO2 and Pd/TiO2 systems in the photocatalytic biohydrogen production from glucose solution

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    Two different catalysts consisting of Pt/TiO2 and Pd/TiO 2 were submitted to diverse oxidative and reductive calcination treatments and tested for photocatalytic reforming of glucose water solution (as a model of biomass component) in H2 production. Oxidation and reduction at 850°C resulted in better photocatalysts for hydrogen production than Degussa P-25 and the ones prepared at 500°C, despite the fact that the former consisted in very low surface area (6-8 m2/g) rutile titania specimens. The platinum-containing systems prepared at 850°C give the most effective catalysts. XPS characterization of the systems showed that thermal treatment at 850°C resulted in electron transfer from titania to metal particles through the so-called strong metal-support interaction (SMSI) effect. Furthermore, the greater the SMSI effect, the better the catalytic performance. Improvement in photocatalytic behavior is explained in terms of avoidance of electron-hole recombination through the electron transfer from titania to metal particles

    A pharmacometrics model to define docetaxel target in early breast cancer

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    Aims: We aimed to study the relation between pharmacokinetics (PK) and pharmacodynamics (PD) of docetaxel in early breast cancer and recommend a target exposure. Methods: A PK/PD study was performed in 27 early breast cancer patients treated with doxorubicin and cyclophosphamide for 4 cycles followed by 4 cycles of docetaxel 75-100 mg/m2 infused every 21 days. Individual Bayesian estimates of docetaxel PK parameters were obtained using a nonparametric population PK model developed with data from patients with metastatic breast cancer who received dose-intensified docetaxel (300-350 mg/m2 ). Docetaxel area under the curve (AUC) and maximum concentration (Cmax) in each cycle and total cumulative AUC (AUCcum) were calculated and related to the incidence of adverse effects and tumour recurrence. Results: Docetaxel clearance showed no change over the 4 treatment cycles, but a gradual increase in the volume of distribution was observed. One third of the patients had at least 1 dose reduction of docetaxel due to toxicity. The mean AUC, AUCcum and Cmax in patients showing docetaxel-associated adverse events were significantly higher than in patients free of toxicity (P 4.5 mg*h/L and 3.5 mg/L, respectively, were risk factors for docetaxel toxicity, while an AUC <4.5 mg*h/L was associated with tumour recurrence. Conclusion: We report for the first time a relation between docetaxel exposure and toxicity and recommend specific targets of drug exposure with implications for the clinical management of early breast cancer patients

    Living in a transient world: ICP-MS reinvented via time-resolved analysis for monitoring single events

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    After 40 years of development, inductively coupled plasma-mass spectrometry (ICP-MS) can hardly be considered as a novel technique anymore. ICP-MS has become the reference when it comes to multi-element bulk analysis at (ultra)trace levels, as well as to isotope ratio determination for metal(loid)s. However, over the last decade, this technique has managed to uncover an entirely new application field, providing information in a variety of contexts related to the individual analysis of single entities (e.g., nanoparticles, cells, or micro/nanoplastics), thus addressing new societal challenges. And this profound expansion of its application range becomes even more remarkable when considering that it has been made possible in an a priori simple way: by providing faster data acquisition and developing the corresponding theoretical substrate to relate the time-resolved signals thus obtained with the elemental composition of the target entities. This review presents the underlying concepts behind single event-ICP-MS, which are needed to fully understand its potential, highlighting key areas of application (e.g., single particle-ICP-MS or single cell-ICP-MS) as well as of future development (e.g., micro/nanoplastics)

    Intraoperative radiotherapy electron boost followed by moderate doses of external beam radiotherapy in resected soft-tissue sarcoma of the extremities

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    To analyze the patterns of failure and the toxicity profile of intraoperative electron beam radiotherapy (IOERT) after resection of soft tissue sarcomas of the extremities (STS). PATIENTS AND METHODS: Forty-five patients with extremity STS were treated with IOERT and moderate-dose postoperative radiotherapy (45-50 Gy). Twenty-six patients were treated for primary disease (PD) and 19 patients for an isolated recurrence (ILR). Tumor size was >5 cm (maximum diameter) in 36 patients (80%), and high-grade histology in PD patients was present in 14 patients (54%). In nine patients, IOERT was used alone, due to previous irradiation or patient refusal. Chemotherapy (neoadjuvant and/or adjuvant) was mainly given to high-grade tumors. RESULTS: Nine patients relapsed in the extremity (20%), and 12 patients in distant sites (28%). Actuarial local control at 5 years was 88% for patients with negative/close margins and 57% for patients presenting positive margins (P=0.04). Five patients (11%) developed neuropathy associated with the treatment. Extremity preservation was achieved in 40 patients (88%). With a median follow-up of 93 months (range: 27-143 months) for the patients at risk, 25 patients remain alive (a 7-year actuarial survival rate of 75% for PD and 47% for ILR; P=0.01). CONCLUSIONS: IOERT combined with moderate doses of external beam irradiation yields high local control and extremity preservation rates in resected extremity STS. Peripheral nerves in the IOERT field are dose-limiting structures requiring a dose compromise in the IOERT component to avoid severe neurological damage

    A country-level primary-final-useful (CL-PFU) energy and exergy database: overview of its construction and 1971–2020 world-level efficiency results

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    Societal exergy analysis examines the flows of energy and exergy through societies, from primary (e.g. oil) to final (e.g. gasoline) to useful (e.g. propulsion) energy stages. By extending the study of energy to the useful stage, new insights into the under-represented role of energy in economic growth have been made. However, currently (a) country coverage is patchy and incomplete, (b) available data are based on varying methods and assumptions including efficiencies based on economic rather than engineering data, and (c) datasets are constructed using piecemeal computational approaches. To address these gaps, we construct a country-level primary-final-useful (CL-PFU) energy and exergy database for the period 1960–2020, containing country-level data created by a consistent physical approach, covering 152 individual countries and 3 rest of world regions, 7 aggregate and 46 detailed sub-sectors, 68 final energy products, and 85 final-to-useful (FU) energy conversion devices. This paper (a) provides details of CL-PFU database construction and its input datasets and (b) gives world-level primary-final-useful energy, exergy, and efficiency results for 1971–2020. We find that whilst world efficiency (including animal and human muscle work) has decreased over primary-to-final stages from 79% to 72% for energy and from 79% to 70% for exergy, there has been a much larger increase in world FU efficiency, which has grown from 37% to 65% in energy terms and from 15% to 23% in exergy terms. This large rise in FU efficiency leads to much larger gains in useful energy (3.71 × 1971 value) and useful exergy (3.20 × 1971 value) than at primary (2.33 × 1971 value) or final (2.10 × 1971 value) stages. Muscle work contributes only a small (less than 10%, and declining) share at primary, final, and useful energy stages

    Strategy revision opportunities and collusion

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    This paper studies whether and how strategy revision opportunities affect levels of collusion in indefinitely repeated two-player games. Consistent with standard theory, we find that such opportunities do not affect strategy choices, or collusion levels, if the game is of strategic substitutes. In games of strategic complements, by contrast, revision opportunities lead to more collusion. We discuss alternative explanations for this result

    Arrays on disc for screening and quantification of pollutants

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    A rapid compact disc based methodology for screening and quantification of organic pollutants in mandarin juices is presented. The assay is established on the coating conjugate indirect competitive principle and developed under disc-array configuration. The detection is based on the acquisition of attenuated reflective signals that were proportional to optical density of the immunoreaction product. The competitive assay is applied to quantify simultaneously, in a selective manner, non-systemic insecticides in mandarin juices. The detection limits were 0.2 and 0.1 ¿g L¿1 and the sensitivity 2.1 and 1.5 ¿g L¿1, for chlorpyrifos and fenthion, respectively. Pollutants were directly quantified after sample dilution in a total time of 40 min. Also, the implementation of positive and negative controls into the array configuration served as an automatic quality control test. The effect of thermal treatment on pesticide dissipation was studied and found that it was insignificant under the studied conditions. Recovery intervals ranged from 96¿105% to 94¿103%, for chlorpyrifos and fenthion, respectively and were similar to those obtained with gas chromatography coupled to mass spectrometry. In the current configuration, 64 samples can be simultaneously analyzed on a disc at a very competitive value, demonstrating its potential for high-throughput multiplexed screening applications for controlled monitoring programs in low-level labs or outside the lab settingThis work was funded by the projects FEDER CTQ2010-15943 (CICYT, Spain), and PROMETEO 2010/008 and ACOMP/2012/158 (Generalitat Valenciana).Navarro, P.; Morais Ezquerro, SB.; Gavaldón, JA.; PÊrez, AJ.; Puchades Pla, R.; Maquieira Catala, Á. (2013). Arrays on disc for screening and quantification of pollutants. Analytica Chimica Acta. 784:59-64. https://doi.org/10.1016/j.aca.2013.04.041S596478

    Surface Photochemistry: 3,3′-Dialkylthia and Selenocarbocyanine Dyes Adsorbed onto Microcrystalline Cellulose

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    In this work, thia and selenocarbocyanines with n-alkyl chains of different length, namely with methyl, ethyl, propyl, hexyl and decyl substituents, were studied in homogeneous and heterogeneous media for comparison purposes. For both carbocyanine dyes adsorbed onto microcrystalline cellulose, a remarkable increase in the fluorescence quantum yields and lifetimes were detected, when compared with solution. Contrary to the solution behaviour, where the increase in the n-alkyl chains length increases to a certain extent the fluorescence emission ΦF and τF, on powdered solid samples a decrease of ΦF and τF was observed. The use of an integrating sphere enabled us to obtain absolute ΦF’s for all the powdered samples. The main difference for liquid homogeneous samples is that the increase of the alkyl chain strongly decreases the ΦF values, both for thiacarbocyanines and selenocarbocyanines. A lifetime distribution analysis for the fluorescence of these dyes adsorbed onto microcrystalline cellulose, evidenced location on the ordered and crystalline part of the substrate, as well as on the more disordered region where the lifetime is smaller. The increase of the n-alkyl chains length decreases the photoisomer emission for the dyes adsorbed onto microcrystalline cellulose, as detected for high fluences of the laser excitation, for most samples

    Determination of diquat by flow injection-chemiluminescence

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    A simple, economic, sensitive and rapid method for the determination of the pesticide diquat was described. This new method was based on the coupling of flow injection analysis methodology and direct chemiluminescent detection; to the authors' knowledge, this approach had not been used up to now with this pesticide. It was based on its oxidation with ferricyanide in alkaline medium; significant improvements in the analytical signal were achieved by using high temperatures and quinine as sensitiser. Its high throughput (144 h(-1)), together with its low limit of detection (2 ng mL(-1)), achieved without need of preconcentration steps, permitted the reliable quantification of diquat over the linear range of (0.01-0.6) mu g mL(-1) in samples from different origins (river, tap, mineral and ground waters), even in the presence of a 40-fold concentration of paraquat, a pesticide commonly present in the commercial formulations of diquat.López-Paz, JL.; Catalá-Icardo, M.; Antón Garrido, B. (2009). Determination of diquat by flow injection-chemiluminescence. Analytical and Bioanalytical Chemistry. 394(4):1073-1079. doi:10.1007/s00216-009-2609-zS107310793944Hayes WJ Jr, Laws ER Jr (1991) Handbook of pesticide toxicology, Academic Press, San DiegoUS Environmental Protection Agency. http://www.epa.gov/06WDW/contaminants/dw_contamfs/diquat.html (accessed in August 2008)Horwitz W (2000) Official methods of analysis of AOAC International 17th edition. AOAC International, Gaithersburg, MD, USAHara S, Sasaki N, Takase D, Shiotsuka S, Ogata K, Futagami K, Tamura K (2007) Anal Sci 23(5):523–531Rial Otero R, Cancho Grande B, Pérez Lamela C, Simal Gandara J, Aria Estevez M (2006) J Chromatogr Sci 44(9):539–542Aramendia MA, Borau V, Lafont F, Marinas JM, Moreno JM, Porras JM, Urbano FJ (2006) Food Chem 97(1):181–188Nuñez O, Moyano E, Galceran MT (2004) Anal Chim Acta 525(2):183–190Martinez Vidal JL, Belmonte Vega A, Sanchez Lopez FJ, Garrido Frenich AJ (2004) Chromatogr A 1050(2):179–184Lee XP, Kumazawa T, Fujishiro M, Hasegawa C, Arinobu T, Seno H, Sato K (2004) J Mass Spectrom 39(10):1147–1152De Almeida RM, Yonamine M (2007) J Chromatogr B 853(1–2):260–264De Souza D, Machado SAS (2006) Electroanalysis 18(9):862–872De Souza D, Da Silva MRC, Machado SAS (2006) Electroanalysis 18(23):2305–2313Picó Y, Rodriguez R, Manes J (2003) Trends Anal Chem 22(3):133–151Ishiwata T (2004) Bunseki Kagaku 53(8):863–864Carneiro MC, Puignou L, Galcerán MT (2000) Anal Chim Acta 408:263Luque M, Rios A, Valcarcel M (1998) Analyst 123(11):2383–2387Perez Ruiz T, Martínez Lozano C, Tomas V (1991) Int J Environ Anal Chem 44(4):243–252Perez Ruiz T, Martínez Lozano C, Tomas V (1991) Anal Chim Acta 244(1):99–104Townshend A (1990) Analyst 115:495–500López Paz JL, Catalá Icardo M (2008) Anal Chim Acta 625:173–179Pawlicová Z, Sahuquillo I, Catalá Icardo M, García Mateo JV, Martínez Calatayud J (2006) Anal Sci 22:29–34Albert García JR, Catalá Icardo M, Martínez Calatayud J (2006) Talanta 69:608–614Tomlin CDS (1997) The pesticide manual, 11th edn.The British Crop Protection CouncilUKCatalá-Icardo M, Martínez-Calatayud J (2008) Crit Rev Anal Chem 38:118–130Ministerio de Medio Ambiente y Medio Rural y Marino. http://www.marm.es/ (accessed in September 2008)US Environmental Protection Agency. http://www.epa.gov/OGWWDW/contaminants (accessed in October 2008
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