Functionalization of wool with L-cysteine : process characterization and assessment of antimicrobial activity and cytotoxicity

This investigation reports a new biotechnological process that uses L-cysteine (L-Cys) which provides a permanent, nontoxic and effective antimicrobial effect over wool-based materials. This process is simple and carried out via idespread exhausting methods. Typically, wool fabrics are incubated with L-Cys for 50 min at 60°C in a pH 4.8 acetate buffer solution 25 mM, under mild agitation to give a good absorption rate. The minimal inhibitory concentration (MIC) of L-Cys was evaluated by the NCCLS M07-A6 standard method, and the results showed a good antibacterial activity against S. aureus and K. pneumoniae within the range of 6.0 × 10−3 − 4.8 × 10−2 g/mL [MIC 0.6% (w/v)] and 6.0 × 10−3 − 4.8 × 10−2 g/mL [MIC 0.6% (w/v)], respectively. In addition, the antimicrobial activity of the functionalized wool was assessed by the international standard JIS 1902-2002 showing a good inhibition of bacterial growth for an L-Cys concentration of 1% over the weight of fabric, both against Staphylococcus aureus and Klebsiella pneumoniae. Moreover, the biocidal mechanism was found to be related with the increase of sulfhydryl's groups onto wool fibers, which were quantified by the Ellman's reagent (5,5′-Dithio-bis(2-nitrobenzoic acid) method. The new process is easy to perform, non toxic, preserve wool quality and is a novel biomimetic approach that uses antimicrobial amino acids and may open new avenues for the design of biomedical textiles with a broad range of applications in healthcare.Contract grant sponsor: FCT; contract grant number: PTDC/EBB-BIO/113671/2009.Contract grant sponsor: R and D Unit of Textile and Paper Materials, Faculty of Engineering, University of Beira Interior

Comparative studies of the preparation of immunoliposomes with the use of two bifunctional coupling agents and investigation of in vitro immunoliposome-target cell binding by cytofluorometry and electron microscopy

The two coupling agents SPDP (N-succinimidyl-3-(2-pyridyldithio)propionate) and SATA (N-succinimidyl-S-acetylthioacetate) were compared in their efficiency and feasibility to couple monoclonal antibodies (Abs) via thioether linkage to liposomes functionalized by various lipophilic maleimide compounds like Full-size image methyl ester (MP-PL), N-(3-maleimidopropionyl)phosphatidylethanolamide (MP-PE), Full-size image methyl ester (EMC-PL), and N-(6-maleimidocaproyl)phosphatidylethanolamine (EMC-PE). The composition of the liposomes was soy phosphatidylcholine (SPC), cholesterol, maleimide compounds and -tocopherol (1:0.2:0.02:0.01, mol parts), plus N4-oleylcytosine arabinoside (NOAC) as cytostatic prodrug (0.2 mol parts) and a new, lipophilic and highly fluorescent dye N,N′-bis(1-hexylheptyl)-3,4:9,10-perylenebis(dicarboximide) (BHPD, 0.006 mol parts). From the maleimide derivatives MP-PL was the most effective in terms of preservation of the coupling activity in dependence of liposome storage. The coupling of the monoclonal A B8-24.3 (mouse IgG2b, MHC class I, anti H-2kb) and IB16-6 (rat IgG2a, anti B16 mouse melanoma) to the drug carrying liposomes was more effective and easier to accomplish with SATA as compared to SPDP. Coupling rates of 60–65% were obtained with SATA at molar ratios of 12 SATA:1 Ab:40 maleimide spacer groups on the surface of one liposome. The highest coupling rates with SPDP were obtained at the ratio of 24 SPDP:1 Ab:40 liposomal maleimide groups, with an Ab binding efficiency of only 20–25%. The optimal in vitro binding conditions to specific target cells (EL4 for B8-24.3-liposomes and B16-F10 for IB16-6-liposomes) were determined by cytofluorometric measurement of the liposomal BHPD fluorescence with SATA linked Abs. Optimal immunoliposome binding to specific epitopes on the target cells was achieved with 1–2 Ab molecules coupled to one liposome, with immunoliposome concentrations of 20–130 nM and with a small incubation volume of 0.3–0.4 ml. The specificity of the binding of B8-24.3-liposomes to EL4 target cells was visualized by scanning electron microscopy. Antibody mediated endocytic uptake of immunoliposomes could be demonstrated by transmission electron microscopy

The synthesis and characterization of water-reducible nanoscale colloidal unimolecular polymer (CUP) particles

The coatings industry has adapted to more stringent guidelines in paint formulations. Current VOC (volatile organic compound) limits placed by the federal government have pushed the industry toward the development of paint formulations which have very little to no VOC\u27s. The development of Colloidal Unimolecular Polymer (CUP) particles is a step in the direction of providing a resin system which exists in zero VOC aqueous dispersion. The CUP particles are a part of the polymer field of Single Chain Nano Particles (SCNP) and ranged in diameters of 3-9 nm. The research presented in this dissertation describes the synthesis and design of these particles along with the various means of instrumentation used to gain insight into the structure and nature of these particles when suspended in aqueous medium --Abstract, page iv

Parliament of Owls

In this work of poems, I experiment with different forms (villanelles, sonnets, cinquains, sestinas, prose poems, and free verse) to create an original accompanying space for the existence of my speakers. I also use many of my poems to illustrate moments, feelings, and scenarios of relationships as well as place new perspectives on poems based on the work of other poets. Parliament of Owls provides an array of vistas on relationships, loneliness, and triumph

Propensity score adjusted method for missing data

Propensity score adjustment is a popular technique for handling unit nonresponse in sample surveys. When the response probability does not depend on the study variable that is subject to missingness, conditional on the auxiliary variables that are observed throughout the sample, the response mechanism is often called missing at random (MAR) or ignorable, and the propensity score can be computed using the auxiliary variables. On the other hand, if the response probability depends on the study variable that is subject to missingness, the response mechanism is often called not missing at random (NMAR) or nonignorable, and estimating the response probability requires additional distributional assumptions about the study variable. In this dissertation, we investigate the propensity-score-adjustment method and the asymptotic properties of the estimators under two different assumptions, MAR and NMAR. We discuss some asymptotic properties of propensity-score-adjusted(PSA) estimators and derive optimal estimators based on a regression model for the finite population under MAR. An optimal propensity-score-adjusted estimator can be implemented using an augmented propensity model. Variance estimation is discussed, and the results from two simulation studies are presented. We also consider the NMAR case with an explicit parametric model for response probability and propose a parameter estimation method for the response model that is based on the distributional assumptions of the observed part of the sample instead of making fully parametric assumptions about the population distribution. The proposed method has the advantage that the model for the observed part of the sample can be verified from the data, which leads to an estimator that is less sensitive to model assumptions. Under NMAR, asymptotic properties of PSA estimators are presented, variance estimation is discussed, and results from two limited simulation studies are presented to compare the performance of the proposed method with the existing methods

A four-helix bundle stores copper for methane oxidation

Methane-oxidising bacteria (methanotrophs) require large quantities of copper for the membrane-bound (particulate) methane monooxygenase (pMMO). Certain methanotrophs are also able to switch to using the iron-containing soluble MMO (sMMO) to catalyse methane oxidation, with this switchover regulated by copper. MMOs are Nature’s primary biological mechanism for suppressing atmospheric levels of methane, a potent greenhouse gas. Furthermore, methanotrophs and MMOs have enormous potential in bioremediation and for biotransformations producing bulk and fine chemicals, and in bioenergy, particularly considering increased methane availability from renewable sources and hydraulic fracturing of shale rock. We have discovered and characterised a novel copper storage protein (Csp1) from the methanotroph Methylosinus trichosporium OB3b that is exported from the cytosol, and stores copper for pMMO. Csp1 is a tetramer of 4-helix bundles with each monomer binding up to 13 Cu(I) ions in a previously unseen manner via mainly Cys residues that point into the core of the bundle. Csp1 is the first example of a protein that stores a metal within an established protein-folding motif. This work provides a detailed insight into how methanotrophs accumulate copper for the oxidation of methane. Understanding this process is essential if the wide-ranging biotechnological applications of methanotrophs are to be realised. Cytosolic homologues of Csp1 are present in diverse bacteria thus challenging the dogma that such organisms do not use copper in this location

Synthetic Magnetic Resonance Imaging Revisited

Synthetic magnetic resonance (MR) imaging is an approach suggested in the literature to predict MR images at different design parameter settings from at least three observed MR scans. However, performance is poor when no regularization is used in the estimation and otherwise computationally impractical to implement for three-dimensional imaging methods. We propose a method which accounts for spatial context in MR images by the imposition of a Gaussian Markov Random Field (MRF) structure on a transformation of the spin-lattice relaxation time, the spin-spin relaxation time and the proton density at each voxel. The MRF structure is specified through a Matrix Normal distribution. We also model the observed magnitude images using the more accurate but computationally challenging Rice distribution. A One-Step-Late Expectation-Maximization approach is adopted to make our approach computationally practical. We evaluate predictive performance in generating synthetic MR images in a clinical setting: our results indicate that our suggested approach is not only computationally feasible to implement but also shows excellent performance

Coal Slurry Pipeline

Coal, a primary energy source, is presently fueling the fires of debate in Virginia. The controversy has arisen over a plan developed by private investors to construct a coal slurry pipeline. The pipeline, as proposed, would transport between five and twenty-five million tons of coal annually from southwest Virginia to the Tidewater area. The coal would be pulverized and combined in a fifty percent mixture with water. Once the coal reaches its destination, the water would be extracted by centrifuge, leaving the coal ready for use

Cultural production and the struggle for authenticity : a Study of the Rastafarian student organization at the University of the Western Cape

Magister Artium - MAThis thesis explores the precarious nature of authenticity as it manifested itself in the activities of H.I.M. Society, the Rastafarian student organization at the University of the Western Cape. Ethnographic research was conducted, to explore the above mentioned issue, which involved observation of various activities and in depth interviews. I also inquired about outsiders' perspectives on Rastafarianism and H.I.M. Society in particular. Authenticity, as it is conceived in this thesis, is about what a group of people deem culturally important. Three important ideas follow from this. The first is that not everyone in a group agrees on what is important. Put differently authenticating processes tend to be characterized by legitimizing crises. Therefore, secondly, social actors need to invest cultural ideas, objects and practices with authenticity. Lastly the authenticating processes are predicated on boundaries not necessarily as a means of exclusion but as fundamental to determining the core of cultural being and belongin

Multi-responsive “turn-on” nanocarriers for efficient site-specific gene delivery in vitro and in vivo

This is an accepted manuscript of an article published by Wiley in Advanced Healthcare Materials on 25/09/2016, available online: https://doi.org/10.1002/adhm.201600710 The accepted version of the publication may differ from the final published version.Systemic gene delivery is a complicated and multistep process that confronts numerous biological barriers. It remains a formidable challenge to exploit a single gene carrier with multiple features to combat all obstacles collectively. Herein, a multi-responsive “turn-on” polyelectrolyte complex (DNA/OEI-SSx/HA-SS-COOH, DSS) delivery system is demonstrated with a sequential self-assembly of disulfide-conjugated oligoethylenimine (OEI-SSx) and disulfide bond-modified hyaluronic acid envelope (HA-SS-COOH) that can combat multiple biological barriers collectively when administered intravenously. DSS is designed to effectively accumulate at the tumor tissue and to be internalized into tumor cells by recognizing CD44. The multi-responsive “turn-on” DSS can respond to the alterations of hyaluronidases and glutathione at both the tumor site and at the intracellular milieu. Sequential degradation and detachment of the HA-SS-COOH envelope followed by the dissociation of the OEI-SSx/DNA inner core contributes to the activation of the endosomal escape and gene release functions, thus greatly enhancing nuclear gene delivery. A systematic investigation of DSS has revealed that the tumor accumulation ability, internalization, and endosome escape of the DSS nanocarriers, DNA unpacking and nuclear transportation are all remarkably improved by the multi-responsive “turn-on” design resulting in highly efficient gene transfection in vitro and in vivo