1,191 research outputs found
Mozambique Cashew reforms revisited
Cashew policy reforms in Mozambique have been controversial. They are often invoked by critics as an illustration of how agricultural policy reforms supported by international financial institutions may fail to have their intended effects. This paper revisits the reforms and their outcomes almost two decades later. While the reforms resulted in higher producer prices and an increase in output, lack of consensus on the specifics of the reforms and associated non-price support arrangements created a situation in which the sector was not able to withstand international price shocks that ultimately led to a collapse of both the processing industry and cashew production. Non-price support by donors improved the efficiency of the processing industry but this was not complemented by an expansion in cashew nut supply as such support did not extend to smallholder cashew producers. For the reforms to have had their intended results, greater investment in -- and support to -- smallholder production was needed to increase yields and overall output. Such a more comprehensive approach to cashew policy reform would have required a greater focus on achieving consensus on the causes of the cashew sector's problems and agreement by all stakeholders on a common institutional framework for pricing and non-price support.Markets and Market Access,Emerging Markets,Economic Theory&Research,Access to Markets,E-Business
A family of incomplete Hurwitz-Lerch zeta functions of two variables
Srivastava, Hari M./0000-0002-9277-8092WOS:000546781400001Inspired essentially by the work [H. M. Srivastava, M. A. Chaudhry and R. P. Agarwal [The incomplete Pochhammer symbols and their applications to hypergeometric and related functions, Integral Transforms Spec. Funct. 23 (2012), 659-683] (see [16])] , we introduce the families of the incomplete Hurwitz-Lerch Zeta functions of two variables. We then give the integral representations including the Mellin-Barnes contour integral representation, summation formulas, derivative formulas and recurrence relations for the incomplete Hurwitz-Lerch Zeta functions of two variables
One-Step Aqueous Synthesis of Anionic and Cationic AgInS2 Quantum Dots and Their Utility in Improving the Efficacy of ALA-Based Photodynamic Therapy
Silver–indium–sulfide quantum dots (AIS QDs) have potential applications in many areas, including biomedicine. Their lack of regulated heavy metals, unlike many commercialized QDs, stands out as an advantage, but the necessity for alloyed or core–shell structures and related costly and sophisticated processes for the production of stable and high quantum yield aqueous AIS QDs are the current challenges. The present study demonstrates the one-step aqueous synthesis of simple AgInS2 QD compositions utilizing for the first time either a polyethyleneimine/2-mercaptopropionic acid (AIS-PEI/2MPA) mixture or only 2-mercaptopropionic acid (AIS-2MPA) as the stabilizing molecules, providing a AgInS2 portfolio consisting of cationic and anionic AIS QDs, respectively, and tuneable emission. Small AIS QDs with long-term stability and high quantum yields (19–23%) were achieved at a molar ratio of Ag/In/S 1/10/10 in water without any dopant or a semiconductor shell. The theranostic potential of these cationic and anionic AIS QDs was also evaluated in vitro. Non-toxic doses were determined, and fluorescence imaging potential was demonstrated. More importantly, these QDs were electrostatically loaded with zwitterionic 5-aminolevulinic acid (ALA) as a prodrug to enhance the tumor availability of ALA and to improve ALA-induced porphyrin photodynamic therapy (PDT). This is the first study investigating the influence of nanoparticle charge on ALA binding, release, and therapeutic efficacy. Surface charge was found to be more critical in cellular internalization and dark toxicity rather than drug loading and release. Both QDs provided enhanced ALA release at acidic pH but protected the prodrug at physiological pH, which is critical for tumor delivery of ALA, which suffers from low bioavailability. The PDT efficacy of the ALA-loaded AIS QDs was tested in 2D monolayers and 3D constructs of HT29 and SW480 human colon adenocarcinoma cancer cell lines. The incorporation of ALA delivery by the AIS QDs, which on their own do not cause phototoxicity, elicited significant cell death due to enhanced light-induced ROS generation and apoptotic/necrotic cell death, reducing the IC50 for ALA dramatically to about 0.1 and 0.01 mM in anionic and cationic AIS QDs, respectively. Combined with simple synthetic methods, the strong intracellular photoluminescence of AIS QDs, good biocompatibility of especially the anionic AIS QDs, and the ability to act as drug carriers for effective PDT signify that the AIS QDs, in particular AIS-2MPA, are highly promising theranostic QDs
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Implementation of a simplified method for actuation of ferrofluids
This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.Magnetic actuation of ferrofluids is an emergent field that will open up new possibilities in various fields of engineering. The quality and topology of the magnetic field that is being utilized in such systems is determinant in terms of flow properties, flow rates and overall efficiency. Determining the optimal magnetic
field topology to achieve the desired results, and determining the methods by which these magnetic fields are to be generated are central problems of obtaining the desired flow. A healthy comparison of various magnetic field topologies requires a varied set of examples from the most simplified to most sophisticated. Such comparisons are necessary to have a well grounded starting point. This study focuses on a particular pump design that employs a simplified magnetic field topology to obtain ferrofluid flow. The results of this paper such as flow and pressure difference are intended to form a baseline for future reference.Sabancı University Internal Research Grant, no: IACF09-0064
In Situ Synthesis of Polymer/Clay Nanocomposites by Type II Photoinitiated Free Radical Polymerization
Cataloged from PDF version of article.A new synthetic route for the preparation of poly(methyl methacrylate)/montmorillonite (PMMA/MMT) nanocomposites was reported. In this method, first 4-(dimethylamino)benzoate group was incorporated into silicate layers of clay by esterification reaction and used to produce PMMA/MMT nanocomposites by in situ Type II photoinitiated free radical polymerization. In situ photopolymerization of methyl methacrylate through into the silicate layers by either visible or UV light irradiation leads to PMMA/MMT nanocomposites. Copyright © 2011 Wiley Periodicals, Inc
Forging a potent vaccine adjuvant: CpG ODN/cationic peptide nanorings
Cataloged from PDF version of article.Type I interferon inducers may potentially be engineered to function as antiviral and anticancer agents, or alternatively, vaccine adjuvants, all of which may have clinical applications. We recently described a simple strategy to convert a Toll-like receptor 9 (TLR9) agonist devoid of interferon alpha (IFN alpha) stimulating activity into a robust Type I interferon inducer with potent vaccine adjuvant activity
Polysulfone/Clay Nanocomposites by in situ Photoinduced Crosslinking Polymerization
Cataloged from PDF version of article.PSU/MMT nanocomposites are prepared by dispersing MMT nanolayers in a PSU matrix via in situ photoinduced crosslinking polymerization. Intercalated methacrylate-functionalized MMT and polysulfone dimethacrylate macromonomer are synthesized independently by esterification. In situ photoinduced crosslinking of the intercalated monomer and the PSU macromonomer in the silicate layers leads to nanocomposites that are formed by individually dispersing inorganic silica nanolayers in the polymer matrix. The morphology of the nanocomposites is investigated by XRD and TEM, which suggests the random dispersion of silicate layers in the PSU matrix. TGA results confirm that the thermal stability and char yield of PSU/MMT nanocomposites increases with the increase of clay loading
Immunostimulatory activity of polysaccharide-poly(I:C) nanoparticles
Cataloged from PDF version of article.Immunostimulatory properties of mushroom derived polysaccharides (PS) as stand-alone agents were tested. Next. PS were nanocomplexed with polyI:C (pIC) to yield stable nanoparticles around 200 nm in size evidenced by atomic force microscopy and dynamic light scattering analyses. PSs were selectively engaged by cells expressing TLR2 and initiated NF kappa B dependent signaling cascade leading to a Th1-biased cytokine/chemokine secretion in addition to bactericidal nitric oxide (NO) production from macrophages. Moreover, cells treated with nanoparticles led to synergistic IL6, production and upregulation of TNF alpha, MIP3 alpha, IFN gamma and IP10 transcript expression. In mice, PS-Ovalbumin-pIC formulation surpassed anti-OVA IgG responses when compared to either PS-OVA or pIC-OVA mediated immunity. Our results revealed that signal transduction initiated both by TLR2 and TLR3 via co-delivery of pIC by PS in nanoparticle depot delivery system is an effective immunization strategy. The present work implicate that the PS and nucleic acid based nanoparticle approach along with protein antigens can be harnessed to prevent infectious diseases. (C) 2011 Elsevier Ltd. All rights reserve
Heparin Mimetic Peptide Nanofibers Promote Angiogenesis
Cataloged from PDF version of article.New blood vessel formation (angiogenesis) is one of the most important processes required for functional tissue formation. Induction of angiogenesis is usually triggered by growth factors released by cells. Glycosaminoglycans (e.g., heparan sulphates) in the extracellular matrix aid in proper functioning of these growth factors. Therefore, exogeneous heparin or growth factors were required for promoting angiogenesis in previous regenerative medicine studies. Here we report for the first time induction of angiogenesis by a synthetic nanofibrous peptide scaffold without the addition of any exogenous growth factors or heparin. We designed and synthesized a self-assembling peptide amphiphile molecule that is functionalized with biologically active groups to mimic heparin. Like heparin, this molecule has the ability to interact with growth factors and effectively enhance their bioactivity. The nanofibers formed by these molecules were shown to form a 3D network mimicking the structural proteins in the extracellular matrix. Because of heparin mimicking capabilities of the peptide nanofibers, angiogenesis was induced without the addition of exogenous growth factors in vitro. Bioactive interactions between the nanofibers and the growth factors enabled robust vascularization in vivo as well. Heparin mimetic peptide nanofibers presented here provide new opportunities for angiogenesis and tissue regeneration by avoiding the use of heparin and exogenous growth factors. The synthetic peptide nanofiber scaffolds enriched with proper chemical functional groups shown in this study can be used to induce various desired physiological responses for tissue regeneration. © 2011 American Chemical Society
Polymer/clay nanocomposites through multiple hydrogen-bonding interactions
An 2-ureido-4[1H]pyrimidinone (UPy) motif with self-association capability (through quadruple hydrogen bonds) was successfully anchored onto montmorillonite clay layers. Polymer/clay nanocomposites were prepared by specific hydrogen bonding interactions between surface functionalized silica nanoclays and UPy-bonded supramolecular poly(ethylene glycol) or poly(É-caprolactone). The mixed morphologies including intercalated layers with a non-uniform separation and exfoliated single layers isolated from any stack were determined by combined X-ray diffraction and transmission electron microscopic measurements. Thermal analyses showed that all nanocomposites had higher decomposition temperatures and thermal stabilities compared with neat polymer. The differential scanning calorimetric data implied that the crystallinity of polymers did not show essential changes upon introduction of organomodified UPy clays. © 2014 Wiley Periodicals, Inc
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