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Nista S.V.G.,University of Campinas | Bettini J.,Electronic Microscopy Laboratory | Mei L.H.I.,University of Campinas
Carbohydrate Polymers | Year: 2015

Electrospinning of mucoadhesive membranes is a new and promising field of investigation in the pharmaceutical and biomedical area. The present study explored the electrospinning of two mucoadhesive polymers, chitosan and alginate, to form a core-shell type nanofibers for future applications as controlled drug delivery. Due to the charged functional groups present in these natural polysaccharides, they can complex to yield various nanodevices to be used in controlled release of several active ingredients. In this work, the core-shell type coaxial nanofibers formation was evidenced by the aid of transmission electron microscopy (TEM). Other characterization techniques as scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Infrared spectroscopy (FTIR) and X-ray diffraction (XRD), strongly suggest the formation of different molecular structures of the membranes obtained by the complexation of chitosan and alginate. Swelling rate and weight loss tests followed by SEM analyses confirmed that the nanofiber structure of these membranes were kept even after incubating them for 24 h in water. The results of this work confirmed that core-shell nanofibers made of chitosan and alginate polycomplex is possible to be obtained with success. © 2015 Elsevier Ltd. All rights reserved. Source

Mogili N.V.V.,University of Limerick | Mogili N.V.V.,Electronic Microscopy Laboratory | Tanner D.A.,University of Limerick | Nakahara S.,University of Limerick
Strain | Year: 2016

Strained superlattices (SSLs) are typically found inside the p-n junction area of semiconductor devices and consist of very thin alternating layers of different material. There exists a small lattice mismatch between these materials which results in localised strain, as in the case of germanium-silicon/silicon SSLs. Strain measurements using a convergent beam electron diffraction (CBED) technique inside a transmission electron microscope (TEM) have indicated that the strain measured normal to these germanium-silicon/silicon SSLs varies almost sinusoidally, in spite of theoretical predictions which indicate a much sharper change in strain between these layers. A theoretical formulation involving an elasticity solution has been developed to predict the strain inside these SSL structures. The comparison of theoretical and experimental results clearly quantifies the effect of beam size on the spatial resolution of CBED measurements. Given that beam size is critically dependent on the spot size of the beam, the convergence angle, the specimen thickness and the position of the focused plane, these parameters are all clearly accounted for in the theoretical predictions. © 2016 Wiley Publishing Ltd. Source

Lavazza A.,Electronic Microscopy Laboratory | Tittarelli C.,Istituto Zooprofilattico Sperimentale del Piemonte Liguria e Valle dAosta | Cerioli M.,Epidemiological Unit
Viruses | Year: 2015

Negative staining electron microscopy methods can be employed for the diagnosis of viral particles in animal samples. In fact, negative staining electron microscopy methods are used to identify viruses, especially in minor species and wild animals, when no other methods are available and in cases of rare, emerging or re-emerging infections. In particular, immune-electron-microscopy with convalescent sera is employed to detect etiological agents when there are undiagnosed clinical outbreaks, when alternative diagnostic methods fail due to the lack of immunological reagents and primers, and when there is no indicative clinical suspect. An overview of immune-electron-microscopy with convalescent sera’s use in the diagnosis of new and unsuspected viruses in animals of domestic and wild species is provided through the descriptions of the following four diagnostic veterinary cases: (I) enteric viruses of pigs: Porcine Rotavirus, Porcine Epidemic Diarrhea Virus, Porcine Circovirus and Porcine Torovirus; (II) Rotavirus and astrovirus in young turkeys with enteritis; (III) Parvovirus-like particles in pheasants; and (IV) Lagoviruses: Rabbit Hemorrhagic Disease Virus and European Brown Hare Syndrome Virus. © 2014 by the authors; licensee MDPI, Basel, Switzerland. Source

Darouich S.,Electronic Microscopy Laboratory | Goucha R.,Charles Nicolle Hospital | Jaafoura M.H.,Electronic Microscopy Laboratory | Zekri S.,Electronic Microscopy Laboratory
Ultrastructural Pathology | Year: 2011

Membranoproliferative glomerulonephritis with isolated C3 deposits (MPGNC3) is an uncommon condition characterized by overt glomerular C3 deposits in the absence of immunoglobulins and intramembranous dense deposits. Here the authors describe the clinical and morphological features of primary MPGNC3 in a 13-year-old boy and critically review the previously published cases. The patient presented with nephrotic syndrome and microscopic hematuria. Blood tests revealed very low circulating C3 levels. The renal biopsy exhibited subendothelial, subepithelial, and mesangial deposits, with C3 but not immunoglobulins seen on immunofluorescence. This case and the review of the literature indicate that the serum complement profile with decreased levels of C3 and normal levels of classical pathway components together with glomerular deposits containing exclusively complement C3 is highly suggestive of alternative pathway activation. The diagnosis of acquired and/or genetic complement abnormalities in some cases supports that complement dysregulation is implicated in the pathogenesis of MPGNC3. Such data show great promise to provide new therapy strategies based on modulation of the complement system activity. Copyright © 2011 Informa Healthcare USA, Inc. Source

Anderson S.R.,Electronic Microscopy Laboratory | Esposito D.,Protein Expression Laboratory | Gillette W.,Protein Expression Laboratory | Zhu J.Y.,U.S. Department of Agriculture | And 2 more authors.
Tappi Journal | Year: 2014

Traditional cellulose nanocrystal (CNC) production methods use harsh chemicals, are energetically expensive, and result in a hydrophilic sulfate surface chemistry with limited utility. Enzymatic production of CNCs is a less expensive alternative production method that eliminates the need for harsh chemicals and requires much less energy for mechanical fibrillation and heating. Furthermore, enzymes that selectively degrade the amorphous regions of cellulose fibers, and do not significantly digest the crystalline areas, result in CNCs that retain a hydroxyl group surface chemistry. Retention of hydroxyl groups allows for easier chemical manipulation, and thus an expanded commercial potential. Here we show that cellulase from Aspergillus niger is capable of producing CNC and microfibrillated cellulose (MFC) from well-solubilized kraft pulp feedstock with minimal processing, and that a chimeric cellulase partially digests kraft pulp and live wood feedstock. Additionally, we show that as a feedstock source, milled pulp from bug-killed dead and downed trees has significantly reduced energy requirements to process the feedstock into elementary fibers and MFCs when compared to live wood feedstock sources. Source

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