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Cesar A. Sierra

Bio: Cesar A. Sierra is an academic researcher from National University of Colombia. The author has contributed to research in topics: Heck reaction & Korteweg–de Vries equation. The author has an hindex of 12, co-authored 64 publications receiving 540 citations. Previous affiliations of Cesar A. Sierra include University of Massachusetts Amherst.


Papers
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Journal ArticleDOI
TL;DR: A strong antimicrobial activity against Escherichia coli of Cu-BTC metal-organic frameworks immobilized over cellulosic fibers is reported in this paper, where the in situ synthesis of MOF-199 or HKUST-1 is carried out by exposing carboxymethylated substrates to Cu(OAC)2, 1,3,5-benzenetricarboxylic acid and trie- thylamine solutions following a very specific order.
Abstract: A strong antimicrobial activity against Escherichia coli of Cu-BTC metal-organic frameworks immobilized over cellulosic fibers is hereby reported. The in situ synthesis of Cu-BTC metal-organic frameworks, aka MOF-199 or HKUST-1, onto cellulosic substrates was carried out by exposing carboxymethylated cellulosic substrates to Cu(OAC)2, 1,3,5-benzenetricarboxylic acid and trie- thylamine solutions following a very specific order. Using an in vitro model, in accordance to ASTM E2149-13a, we observed that the cellulose-MOF system was able to completely eliminate the growth of E. coli on agar plates and liquid cultures. The antibacterial activity of the comprising components of MOF-199 and the cellulosic substrate was also evaluated and determined to be negligible. Since the method used to synthesize MOF-199 crystals provides a strong bond between the crystals and the cellulosic substrates, the crystals not detach from the anionic cellulosic fibers allowing the modified textile to be washed and reused hence opening a new avenue to fabricate antibacterial clinical fabrics. V C 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40815.

124 citations

Journal ArticleDOI
TL;DR: In this article, the physicochemical properties of Gulupa (Passiflora edulis Sims) in three maturity stages were investigated. And the results showed an increase in the amount of volatile during fruit ripening, with aliphatic esters as major constituents.

83 citations

Journal ArticleDOI
TL;DR: The aim of the present review is to describe and highlight specific and nonspecific modulators of ABCG2 reported to date based on the selectivity of the compounds, as many of them are effective against one or more ABC transport proteins.
Abstract: Multidrug resistance (MDR) in cancer cells is the development of resistance to a variety of structurally and functionally nonrelated anticancer drugs. This phenomenon has become a major obstacle to cancer chemotherapy seriously affecting the clinical outcome. MDR is associated with increased drug efflux from cells mediated by an energy-dependent mechanism involving the ATP-binding cassette (ABC) transporters, mainly P-glycoprotein (ABCB1), the MDR-associated protein-1 (ABCC1), and the breast cancer resistance protein (ABCG2). The first two transporters have been widely studied already and reviews summarized the results. The ABCG2 protein has been a subject of intense study since its discovery as its overexpression has been detected in resistant cell lines in numerous types of human cancers. To date, a long list of modulators of ABCG2 exists and continues to increase. However, little is known about the clinical consequences of ABCG2 modulation. This makes the design of novel, potent, and nontoxic inhibitors of this efflux protein a major challenge to reverse MDR and thereby increase the success of chemotherapy. The aim of the present review is to describe and highlight specific and nonspecific modulators of ABCG2 reported to date based on the selectivity of the compounds, as many of them are effective against one or more ABC transport proteins.

48 citations

Journal ArticleDOI
TL;DR: The optical absorption of UiO-66-NH2 MOF was red-shifted using a diazo-coupling reaction and the degradation performance was found to correlate with the red shift of the absorption edge, suggesting potential applications of these materials in photocatalysis and in dye sensitized solar cells.

42 citations

Journal ArticleDOI
TL;DR: A generalization of the well-known tanh–coth method is used to obtain new periodic and soliton solutions for several forms of the fifth-order KdV equation (fKdV).

36 citations


Cited by
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Journal ArticleDOI
10 Mar 1970

8,159 citations

Journal ArticleDOI
TL;DR: To the best of our knowledge, there is only one application of mathematical modelling to face recognition as mentioned in this paper, and it is a face recognition problem that scarcely clamoured for attention before the computer age but, having surfaced, has attracted the attention of some fine minds.
Abstract: to be done in this area. Face recognition is a problem that scarcely clamoured for attention before the computer age but, having surfaced, has involved a wide range of techniques and has attracted the attention of some fine minds (David Mumford was a Fields Medallist in 1974). This singular application of mathematical modelling to a messy applied problem of obvious utility and importance but with no unique solution is a pretty one to share with students: perhaps, returning to the source of our opening quotation, we may invert Duncan's earlier observation, 'There is an art to find the mind's construction in the face!'.

3,015 citations

Journal ArticleDOI
01 Jan 1977-Nature
TL;DR: Bergh and P.J.Dean as discussed by the authors proposed a light-emitting diode (LEDD) for light-aware Diodes, which was shown to have promising performance.
Abstract: Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

1,560 citations

01 Sep 1976
TL;DR: In this article, the authors present a direct and systematic way of finding exact solutions and Backlund transformations of a certain class of nonlinear evolution equations, which they solve exactly using a kind of perturbational approach.
Abstract: The main purpos e of this chapter is to present a direct and systematic way of finding exact solutions and Backlund transformations of a certain class of nonlinear evolution equations. The nonlinear evolution equations are transformed, by changing the dependent variable(s), into bilinear differential equations of the following special form $$ F\left( {\frac{\partial }{{\partial t}} - \frac{\partial }{{\partial {t^1}}},\frac{\partial }{{\partial x}} - \frac{\partial }{{\partial {x^1}}}} \right)f(t,x)f({t^1},{x^1}){|_{t = {t^1},x = {x^1}}} = 0 $$ , which we solve exactly using a kind of perturbational approach.

612 citations

Journal ArticleDOI
TL;DR: This review focuses on recent progress in the application of MOFs in electrocatalytic and photocatalytic water splitting for hydrogen generation, including both oxygen and hydrogen evolution.
Abstract: The development of clean and renewable energy materials as alternatives to fossil fuels is foreseen as a potential solution to the crucial problems of environmental pollution and energy shortages. Hydrogen is an ideal energy material for the future, and water splitting using solar/electrical energy is one way to generate hydrogen. Metal-organic frameworks (MOFs) are a class of porous materials with unique properties that have received rapidly growing attention in recent years for applications in water splitting due to their remarkable design flexibility, ultra-large surface-to-volume ratios and tunable pore channels. This review focuses on recent progress in the application of MOFs in electrocatalytic and photocatalytic water splitting for hydrogen generation, including both oxygen and hydrogen evolution. It starts with the fundamentals of electrocatalytic and photocatalytic water splitting and the related factors to determine the catalytic activity. The recent progress in the exploitation of MOFs for water splitting is then summarized, and strategies for designing MOF-based catalysts for electrocatalytic and photocatalytic water splitting are presented. Finally, major challenges in the field of water splitting are highlighted, and some perspectives of MOF-based catalysts for water splitting are proposed.

533 citations