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  • MEDLINE/PubMed (NLM)  (25)
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  • 1
    Language: English
    In: Science of the Total Environment, 01 December 2015, Vol.535, pp.122-130
    Description: The widespread use of engineered inorganic nanoparticles (EINP) leads to a growing risk for an unintended release into the environment. Despite the good characterization of EINP in regard to their function scale and the application areas, there is still a gap of knowledge concerning their behaviour in the different environmental compartments. Due to their high surface to volume ratio, surface properties and existence or development of a coating are of high importance for their stability and transport behaviour. However, analytical methods to investigate organic coatings on nanoparticles in aqueous media are scarce. We used Raman microspectroscopy in combination with surface-enhanced Raman scattering (SERS) to investigate humic acid coatings on silver nanoparticles under environmentally relevant conditions and in real world samples. This setup is more challenging than previous mechanistic studies using SERS to characterize the humic acids in tailored settings where only one type of organic matter is present and the concentrations of the nanoparticles can be easily adjusted to the experimental needs. SERS offers the unique opportunity to work with little sample preparation directly with liquid samples, thus significantly reducing artefacts. SERS spectra of different natural organic matter brought into contact with silver nanoparticles indicate humic acid in close proximity to the nanoparticles. This coating was also present after several washing steps by centrifugation and resuspension in deionized water and after an increase in ionic strength.
    Keywords: Engineered Inorganic Nanoparticles ; Coatings ; Natural Organic Matter ; Surface-Enhanced Raman Scattering ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 2
    Language: English
    In: Science of the Total Environment, 01 December 2015, Vol.535, pp.3-19
    Description: Engineered inorganic nanoparticles (EINP) from consumers' products and industrial applications, especially silver and titanium dioxide nanoparticles (NP), are emitted into the aquatic and terrestrial environments in increasing amounts. However, the current knowledge on their environmental fate and biological effects is diverse and renders reliable predictions complicated. This review critically evaluates existing knowledge on colloidal aging mechanisms, biological functioning and transport of Ag NP and TiO NP in water and soil and it discusses challenges for concepts, experimental approaches and analytical methods in order to obtain a comprehensive understanding of the processes linking NP fate and effects. Ag NP undergo dissolution and oxidation with Ag S as a thermodynamically determined endpoint. Nonetheless, Ag NP also undergo colloidal transformations in the nanoparticulate state and may act as carriers for other substances. Ag NP and TiO NP can have adverse biological effects on organisms. Whereas Ag NP reveal higher colloidal stability and mobility, the efficiency of NOM as a stabilizing agent is greater towards TiO NP than towards Ag NP, and multivalent cations can dominate the colloidal behavior over NOM. Many of the past analytical obstacles have been overcome just recently. Single particle ICP-MS based methods in combination with field flow fractionation techniques and hydrodynamic chromatography have the potential to fill the gaps currently hampering a comprehensive understanding of fate and effects also at a low field relevant concentrations. These analytical developments will allow for mechanistically orientated research and transfer to a larger set of EINP. This includes separating processes driven by NP specific properties and bulk chemical properties, categorization of effect-triggering pathways directing the EINP effects towards specific recipients, and identification of dominant environmental parameters triggering fate and effect of EINP in specific ecosystems (e.g. soil, lake, or riverine systems).
    Keywords: Transport ; Aggregation ; Analytics ; Environment ; Aging ; Ecotoxicology ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 3
    Language: English
    In: Environmental science & technology, 21 May 2013, Vol.47(10), pp.5083-91
    Description: The fate of engineered nanoparticles in environmental systems is controlled by changes in colloidal stability and their interaction with different environmental surfaces. Little is known about nanoparticle-surface interactions on the basis of sorption isotherms under quasi-equilibrium conditions, although sorption isotherms are a valuable means of studying sorbate-sorbent interactions. We tested the extent to which the sorption of engineered silver nanoparticles (nAg) from stable and unstable suspensions to model (sorbents with specific chemical functional groups) and environmental (plant leaves and sand) surfaces can be described by classical sorption isotherms. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) qualitative and quantitative analyses were also used to assess the morphology and nanomechanical parameters of the covered surfaces. The sorption of nAg from stable suspensions was nonlinear and best described by the Langmuir isotherm. Langmuir coefficients varied with sorbent surface chemistry. For nAg sorption from an unstable suspension, the sorption isotherms did not follow any classical sorption models, suggesting interplay between aggregation and sorption. The validity of the Langmuir isotherm suggests monolayer sorption, which can be explained by the blocking effect due to electrostatic repulsion of individual nanoparticles. In unstable suspensions, aggregates are instead formed in suspension and then sorbed, formed on the surface itself, or formed in both ways.
    Keywords: Models, Chemical ; Metal Nanoparticles -- Chemistry ; Silver -- Chemistry
    ISSN: 0013936X
    E-ISSN: 1520-5851
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  • 4
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 12 June 2012, Vol.109(24), pp.9354-9
    Description: Gene targeting by zinc-finger nucleases in one-cell embryos provides an expedite mutagenesis approach in mice, rats, and rabbits. This technology has been recently used to create knockout and knockin mutants through the deletion or insertion of nucleotides. Here we apply zinc-finger nucleases in one-cell mouse embryos to generate disease-related mutants harboring single nucleotide or codon replacements. Using a gene-targeting vector or a synthetic oligodesoxynucleotide as template for homologous recombination, we introduced missense and silent mutations into the Rab38 gene, encoding a small GTPase that regulates intracellular vesicle trafficking. These results demonstrate the feasibility of seamless gene editing in one-cell embryos to create genetic disease models and establish synthetic oligodesoxynucleotides as a simplified mutagenesis tool.
    Keywords: Embryo, Mammalian ; Gene Targeting ; Mutation
    ISSN: 00278424
    E-ISSN: 1091-6490
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  • 5
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 05 March 2013, Vol.110(10), pp.3782-7
    Description: The study of genetic disease mechanisms relies mostly on targeted mouse mutants that are derived from engineered embryonic stem (ES) cells. Nevertheless, the establishment of mutant ES cells is laborious and time-consuming, restricting the study of the increasing number of human disease mutations discovered by high-throughput genomic analysis. Here, we present an advanced approach for the production of mouse disease models by microinjection of transcription activator-like effector nucleases (TALENs) and synthetic oligodeoxynucleotides into one-cell embryos. Within 2 d of embryo injection, we created and corrected chocolate missense mutations in the small GTPase RAB38; a regulator of intracellular vesicle trafficking and phenotypic model of Hermansky-Pudlak syndrome. Because ES cell cultures and targeting vectors are not required, this technology enables instant germline modifications, making heterozygous mutants available within 18 wk. The key features of direct mutagenesis by TALENs and oligodeoxynucleotides, minimal effort and high speed, catalyze the generation of future in vivo models for the study of human disease mechanisms and interventions.
    Keywords: Disease Models, Animal ; Germ-Line Mutation ; Genetic Diseases, Inborn -- Genetics ; Oligodeoxyribonucleotides -- Administration & Dosage
    ISSN: 00278424
    E-ISSN: 1091-6490
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  • 6
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 24 August 2010, Vol.107(34), pp.15022-6
    Description: Gene targeting by homologous recombination in embryonic stem cells is extensively used to generate specific mouse mutants. However, most mammalian species lack tools for targeted gene manipulation. Since double-strand breaks strongly increase the rate of homologous recombination at genomic loci, we explored whether gene targeting can be directly performed in zygotes by the use of zinc-finger nucleases. Here we report that gene targeting is achieved in 1.7-4.5% of murine one-cell embryos upon the coinjection of targeting vectors with zinc-finger nucleases, without preselection. These findings enable the manipulation of the mammalian germ line in a single step in zygotes, independent of ES cells.
    Keywords: Endonucleases -- Metabolism ; Gene Targeting -- Methods ; Zygote -- Metabolism
    ISSN: 00278424
    E-ISSN: 1091-6490
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  • 7
    In: Nursing Education Perspectives, 2015, Vol.36(5), pp.304-310
    Description: AIM: The aim of this research was to replicate findings of enhanced clinical reasoning scores using a structured debriefing: Debriefing for Meaningful Learning© (DML). BACKGROUND: The direct effect of debriefing on clinical reasoning is not well studied. The nursing education literature supports debriefing as a reflective dialogue necessary to enhance clinical reasoning. METHOD: A quasi-experimental, pretest-posttest, repeated measure research design was used to evaluate nursing students’ clinical reasoning using the Health Sciences Reasoning Test (HSRT). RESULTS: The change in HSRT mean scores was determined to be significant for the intervention group at the .05 level and insignificant for the control group. The change in HSRT mean scores between the intervention and control groups was determined to be significant at the .10 level. CONCLUSION: Nursing students who had the DML debriefing scored significantly higher in their clinical reasoning than nursing students who had usual and customary debriefing.
    Keywords: Student Nurses ; Decision Making Process ; Education : Assessment ; Reflective Practice ; Decision Making ; Educational Evaluation ; Nursing Education ; Students ; Nursing Education;
    ISSN: 1536-5026
    E-ISSN: 19434685
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  • 8
    Language: English
    In: PLoS ONE, 01 January 2017, Vol.12(4), p.e0174216
    Description: Taxonomic over-splitting of extinct or endangered taxa, due to an incomplete knowledge of both skeletal morphological variability and the geographical ranges of past populations, continues to confuse the link between isolated extant populations and their ancestors. This is particularly problematic with the genus Equus. To more reliably determine the evolution and phylogeographic history of the endangered Asiatic wild ass, we studied the genetic diversity and inter-relationships of both extinct and extant populations over the last 100,000 years, including samples throughout its previous range from Western Europe to Southwest and East Asia. Using 229 bp of the mitochondrial hypervariable region, an approach which allowed the inclusion of information from extremely poorly preserved ancient samples, we classify all non-African wild asses into eleven clades that show a clear phylogeographic structure revealing their phylogenetic history. This study places the extinct European wild ass, E. hydruntinus, the phylogeny of which has been debated since the end of the 19th century, into its phylogenetic context within the Asiatic wild asses and reveals recent mitochondrial introgression between populations currently regarded as separate species. The phylogeographic organization of clades resulting from these efforts can be used not only to improve future taxonomic determination of a poorly characterized group of equids, but also to identify historic ranges, interbreeding events between various populations, and the impact of ancient climatic changes. In addition, appropriately placing extant relict populations into a broader phylogeographic and genetic context can better inform ongoing conservation strategies for this highly-endangered species.
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
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  • 9
    Language: English
    In: 2014, Vol.8(12), p.e3347
    Description: Despite major attempts to prevent cholera transmission, millions of people worldwide still must address this devastating disease. Cholera research has so far mainly focused on the causative agent, the bacterium Vibrio cholerae , or on disease treatment, but rarely were results from both fields interconnected. Indeed, the treatment of this severe diarrheal disease is mostly accomplished by oral rehydration therapy (ORT), whereby water and electrolytes are replenished. Commonly distributed oral rehydration salts also contain glucose. Here, we analyzed the effects of glucose and alternative carbon sources on the production of virulence determinants in the causative agent of cholera, the bacterium Vibrio cholerae during in vitro experimentation. We demonstrate that virulence gene expression and the production of cholera toxin are enhanced in the presence of glucose or similarly transported sugars in a ToxR-, TcpP- and ToxT-dependent manner. The virulence genes were significantly less expressed if alternative non-PTS carbon sources, including rice-based starch, were utilized. Notably, even though glucose-based ORT is commonly used, field studies indicated that rice-based ORT performs better. We therefore used a spatially explicit epidemiological model to demonstrate that the better performing rice-based ORT could have a significant impact on epidemic progression based on the recent outbreak of cholera in Haiti. Our results strongly support a change of carbon source for the treatment of cholera, especially in epidemic settings. ; Cholera research has so far mainly focused on the causative agent, the bacterium , or on disease treatment, but rarely were results from both fields interconnected. Indeed, the treatment of this severe diarrheal disease is mostly accomplished by oral rehydration therapy (ORT). ORT aims at rehydrating patients through the provision of water and oral rehydration salts; the latter being composed of electrolytes as well as glucose as a carbon source. Although glucose-based ORS is commonly used to treat diarrheal diseases and is recommended by the WHO, field studies on cholera indicated that rice-based ORT performs better than glucose-based ORT. Here, we investigated the impact that glucose, starch, or other carbon sources exert on . We demonstrated that glucose leads to an increased expression of the major virulence genes in the pathogen and, accordingly, to an enhanced production of cholera toxin during experimentation. Because the cholera toxin is primarily responsible for the severe symptoms that are associated with the disease, our study highlights the negative effects of glucose-based ORT. Next, we used a spatially explicit epidemiological model to demonstrate that the better performing rice-based ORS could have a significant impact on epidemic progression based on the recent outbreak of cholera in Haiti.
    Keywords: Research Article ; Biology And Life Sciences ; Medicine And Health Sciences
    ISSN: 19352727
    E-ISSN: 1935-2735
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  • 10
    Language: English
    In: Nucleic acids research, 04 January 2016, Vol.44(D1), pp.D294-300
    Description: The Eukaryotic Linear Motif (ELM) resource (http://elm.eu.org) is a manually curated database of short linear motifs (SLiMs). In this update, we present the latest additions to this resource, along with more improvements to the web interface. ELM 2016 contains more than 240 different motif classes with over 2700 experimentally validated instances, manually curated from more than 2400 scientific publications. In addition, more data have been made available as individually searchable pages and are downloadable in various formats.
    Keywords: Amino Acid Motifs ; Databases, Protein
    ISSN: 03051048
    E-ISSN: 1362-4962
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