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51.
Florencia Leonardi Matías Lopez‐Rosenfeld Daniela Rodriguez Magno T. F. Severino Mariela Sued 《时间序列分析杂志》2021,42(1):19-33
In this‐30 work we propose a model selection criterion to estimate the points of independence of a random vector, producing a decomposition of the vector distribution function into independent blocks. The method, based on a general estimator of the distribution function, can be applied for discrete or continuous random vectors, and for i.i.d. data or dependent time series. We prove the consistency of the approach under general conditions on the estimator of the distribution function and we show that the consistency holds for i.i.d. data and discrete time series with mixing conditions. We also propose an efficient algorithm to approximate the estimator and show the performance of the method on simulated data. We apply the method in a real dataset to estimate the distribution of the flow over several locations on a river, observed at different time points. 相似文献
52.
Reaction Between Ethylene and Acetate Species on Clean and Oxygen-Covered Pd(100): Implications for the Vinyl Acetate Monomer Formation Pathway 总被引:1,自引:0,他引:1
Abstract
The reaction between gas-phase ethylene and adsorbed acetate species on Pd(100)-p(2 × 2)-O and Pd(100)-c(2 × 2)-O surfaces is studied using infrared spectroscopy. It is found that acetate species are removed more rapidly by gas-phase ethylene on oxygen-covered Pd(100) than on Pd(111). However, in contrast to reaction on Pd(111), where vinyl acetate monomer (VAM) formation is detected by infrared spectroscopy, only CO is found on oxygen-covered Pd(100) surfaces. In the case of Pd(111), it has been shown that VAM is stabilized on the crowded, ethylidyne-covered surface. Since ethylidyne species do not form on Pd(100), any VAM that is formed can thermally decompose. The reaction shows an isotope effect when C2D4 is substituted for C2H4, indicating the hydrogen is involved in the rate-limiting step. Based on the surface chemistry found for VAM on a Au/Pd(111) alloy, where 30 to 40% ML of gold inhibits VAM decomposition, it is suggested that the VAM formation rate will increase on (100) alloy surfaces, while it will decrease at higher gold coverages since acetate formation is inhibited. 相似文献53.
Teresa Freire Mercedes Landeira Cecilia Giacomini María Florencia Festari lvaro Pittini Viviana Cardozo Alina Brosque Leticia Monin Valeria da Costa Paula Faral-Tello Carlos Robello Eduardo Osinaga 《International journal of molecular sciences》2022,23(23)
Lung cancer remains the leading cause of cancer mortality worldwide. Thus, the development of strategies against this type of cancer is of high value. Parasite infections can correlate with lower cancer incidence in humans and their use as vaccines has been recently explored in preclinical models. In this study, we investigated whether immunisations with a Trypanosoma cruzi lysate from epimastigotes protect from lung tumour growth in mice. We also explore the role of parasite glycans in the induction of the protective immune response. A pre-clinical murine cancer model using the lung tumour cell line LL/2 was used to evaluate the anti-tumour potential, both in preventive and therapeutic settings, of a T. cruzi epimastigote-derived protein lysate. Immunisation with the parasite lysate prevents tumour growth and induces both humoral and cellular anti-tumour immune responses to LL-2 cancer cells. The induced immunity and tumour protection were associated with the activation of natural killer (NK) cells, the production of interferon-γ (IFN-γ) and tumour cell cytotoxicity. We also show that mannose residues in the T. cruzi lysate induce Toll-like receptor (TLR) signalling. The evaluated T. cruzi lysate possesses anti-tumour properties likely by activating innate and adaptive immunity in a process where carbohydrates seem to be essential. 相似文献
54.
Juan Zegers-Delgado Alejandro Aguilera-Soza Florencia Caldern Harley Davidson Daniel Verbel-Vergara Hector E. Yarur Javier Novoa Camila Blanlot Cristian P. Bastias María Estela Andrs Katia Gysling 《International journal of molecular sciences》2022,23(18)
Adversity is particularly pernicious in early life, increasing the likelihood of developing psychiatric disorders in adulthood. Juvenile and adult rats exposed to social isolation show differences in anxiety-like behaviors and significant changes in dopamine (DA) neurotransmission in the nucleus accumbens (NAc). Brain response to stress is partly mediated by the corticotropin-releasing factor (CRF) system, composed of CRF and its two main receptors, CRF-R1 and CRF-R2. In the NAc shell of adult rats, CRF induces anxiety-like behavior and changes local DA balance. However, the role of CRF receptors in the control of neurotransmission in the NAc is not fully understood, nor is it known whether there are differences between life stages. Our previous data showed that infusion of a CRF-R1 antagonist into the NAc of juvenile rats increased DA levels in response to a depolarizing stimulus and decreased basal glutamate levels. To extend this analysis, we now evaluated the effect of a CRF-R1 antagonist infusion in the NAc of adult rats. Here, we describe that the opposite occurred in the NAc of adult compared to juvenile rats. Infusion of a CRF-R1 antagonist decreased DA and increased glutamate levels in response to a depolarizing stimulus. Furthermore, basal levels of DA, glutamate, and γ-Aminobutyric acid (GABA) were similar in juvenile animals compared to adults. CRF-R1 protein levels and localization were not different in juvenile compared to adult rats. Interestingly, we observed differences in the signaling pathways of CRF-R1 in the NAc of juveniles compared to adult rats. We propose that the function of CRF-R1 receptors is differentially modulated in the NAc according to life stage. 相似文献
55.
C Foresta R Mioni P Bordon D Miotto G Montini A Varotto 《Canadian Metallurgical Quarterly》1994,78(3):753-756
Human recombinant erythropoietin (rHuEPO) treatment improves sexual function in end-stage renal failure patients with a still-debated mechanism. Experimental data suggested that rHuEPO was able to stimulate rat Leydig steroidogenesis; therefore, it has been suggested that rHuEPO may induce its effects in humans by acting on gonadal steroid production. Thirteen young adult males (age range, 16-28 yr) catheterized at peripheral and left internal spermatic venous levels during a contrast study for varicocele, were studied. In five subjects, rHuEPO (60 IU/kg, up to a maximum of 4000 IU total) was injected over 1 min in the cubital vein. Similarly, in other five patients, 50 micrograms GnRH were infused. In three subjects, 2 mL saline were injected, as controls. Plasma LH, FSH, and testosterone (T) levels were then determined at -15, 0, 15, 30, 45, 60, 90, and 120 min simultaneously in peripheral and spermatic venous blood. rHuEPO infusion did not have any effect on plasma LH and FSH levels in peripheral or spermatic veins. Similarly, rHuEPO infusion did not affect peripheral T concentration, but increased (approximately 400% vs. controls; P < 0.05) spermatic T levels. GnRH infusion induced an increase in plasma LH and FSH levels in both peripheral and spermatic veins. After GnRH infusion, an increase of approximately 12-fold (P = 0.05-0.001) in T was observed only at the spermatic venous level, without any peripheral T variation. These findings show that rHuEPO was able to influence testicular steroidogenesis by stimulating T production in man, whereas the absence of any effect on gonadotropin secretion suggests that rHuEPO might act directly on human Leydig cell function. 相似文献
56.
I. Alessandri M. A. Bañares L. E. Depero M. Ferroni P. Fornasiero F. C. Gennari N. Hickey M. V. Martinez-Huerta T. Montini 《Topics in Catalysis》2006,41(1-4):35-42
Structural investigations of various aliquots of Ce2Zr2O8 were conducted after application of well-defined redox treatments. The results indicate that specific redox procedures induce
modifications in the ceria–zirconia mixed oxide, which lead to notable effects on the hydrogen uptake temperature during Temperature
Programmed Reduction (TPR). Pyrochlore-type cation ordering is evident for an aliquot which exhibits a single low temperature
peak during TPR. However, the cation ordering is not complete in this case. Furthermore, the analysis indicates less extensive
pyrochlore-type cation ordering for an aliquot which shows a TPR profile in which there are two peaks, one at high temperature
and one at low temperature. Finally, an aliquot that exhibits a single high temperature TPR peak shows no evidence of cation
ordering. The trend in the promotion of reduction to low temperature is associated with the extent of the pyrochlore-type
cation ordering. 相似文献
57.
Juan Manuel Lzaro Martínez María Florencia Leal Denis Lidia Leonor Piehl Emilio Rubín de Celis Graciela Yolanda Buldain Viviana Campo Dall Orto 《Applied catalysis. B, Environmental》2008,82(3-4):273-283
In this work we describe the application of a new non-soluble and non-porous complex with copper ion based on ethylene glycol diglycidyl ether (EGDE), methacrylic acid (MAA) and 2-methylimidazole (2MI) in the decolorization of an azo dye Methyl Orange (MO) as a model pollutant at room temperature.The complex with copper ion was studied by ESR and SEM and was tested as a heterogeneous catalyst for H2O2 activation. A possible mechanism of interaction involves the production of hydroxyl radicals (confirmed by ESR), dioxygen and water.The Cu(II)-polyampholyte/H2O2 system acted efficiently in the color removal of MO. The adsorption and oxidative degradation of the azo-based dye followed pseudo-first-order kinetic profiles, and the rate constant for degradation had a second-order dependence on copper ion content in the mixture.A removal of MO higher than 90% was achieved in 20 min at pH 7.0, combining 0.8 mM of complexed copper ions in the mixture with 24 mM hydrogen peroxide.The dye adsorbed on the polyampholyte following a L4-type isotherm with 4.9 μmol g−1 maximum loading capacity and 3.1 μM dissociation constant for the first monolayer. 相似文献
58.
In this article we have evaluated some of the factors (pH, solvent composition and dye structure) that influence the dyeing of hair with dyes from direct semipermanent categories. These dyes, in fact, have been used more and more in cosmetic industry over the last years, due to their lesser aggressiveness vs. hair fibres. Two different dye classes are investigated: phenylene diamine (HC), well known for their low molecular weight and their small size, and a series of Basic dyes, characterized by the same ionic charge (positive) but with different sizes and different polar groups in the molecule. pH and dyebath composition result critical factors controlling the diffusion and adsorption process. 相似文献
59.
Giovanni Brandi Silvia Turroni Florencia McAllister Giorgio Frega 《International journal of molecular sciences》2021,22(18)
Recent pieces of evidence have emerged on the relevance of microorganisms in modulating responses to anticancer treatments and reshaping the tumor-immune microenvironment. On the one hand, many studies have addressed the role of the gut microbiota, providing interesting correlative findings with respect to etiopathogenesis and treatment responses. On the other hand, intra-tumoral bacteria are being recognized as intrinsic and essential components of the cancer microenvironment, able to promote a plethora of tumor-related aspects from cancer growth to resistance to chemotherapy. These elements will be probably more and more valuable in the coming years in early diagnosis and risk stratification. Furthermore, microbial-targeted intervention strategies may be used as adjuvants to current therapies to improve therapeutic responses and overall survival. This review focuses on new insights and therapeutic approaches that are dawning against pancreatic cancer: a neoplasm that arises in a central metabolic “hub” interfaced between the gut and the host. 相似文献
60.
Relative to the enormous acceptance of the ISO 9000 quality standard, the ISO 14001 environmental management certification has been met with only moderate enthusiasm among industrial facilities. The literature on corporate motivation for ISO 14001 participation is relatively modest considering the enormous number of publications reviewing other aspects of its adoption and implementation. It would seem that the present "marketing" package supporting ISO environmental commitments does not seem to offer sufficiently persuasive incentives for increased sales, either domestically or internationally. While researchers assume that a higher export rate of companies is positively associated with higher ISO participation rates, there have been very few empirical studies that support this inference, and conclusions have not been based on data taken from importing countries orfrom a systematic evaluation of expressed corporate preference for products sold by ISO 14001 certified companies. The present study reports the results of a survey to firms in six countries that are Israel's leading trade partners, importing chemicals, textiles, and produce. The survey results confirm that while the international market still considers price and quality as the paramount factors in selection of suppliers, environmental management systems (EMS) are an important feature that is frequently taken into consideration. EMS certification appears to signify a supplier who is managing the business well and exhibiting ethical responsibility. The European market proved to be more environmentally conscious than those in other industrialized parts of the world. EMS offer a particularly valuable advantage for producers wishing to reach European markets. As policy-makers seek to expand the voluntary adoption of EMS, a clear advantage for exporters should be highlighted among national industries. 相似文献