211 research outputs found

    Effectiveness of some crown compounds on inhibition of polyphenoloxidase in model systems and in apple

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    Enzymatic browning is (in most cases) an undesirable reaction which usually impairs the sensory properties and chemical changes in raw fruits and vegetables after mechanical operations (such as peeling, coring or slicing). A great emphasis is put on research to develop new methods to prevent enzymatic browning especially in fresh-cut (minimally processed) fruits and vegetables. The inhibition effect of crown compounds, macrocyclic ethers, benzo-18-crown-6 with sorbic acid and benzo-18-crown-6 with potassium sorbate, on polyphenoloxidase (PPO) activity was studied. The effectiveness of these compounds was evaluated by using 3,4-dihydroxy phenylalanine (L-DOPA), and chlorogenic acid (3-o-caffeoyl-D-quinic acid), the most widespread natural PPO substrates in fruits and vegetables, as well as browning inhibition substances on the cut surface of apples. Results showed that crown compounds used in this study were effective, both as inhibitors of the oxidation of phenolic compounds (PPO substrates) in model solutions and as inhibitors of enzyme discolorations of real systems (fresh-cut apples). In the earlier published papers (V UKOVI C 'et al., 1999) the synthesis of crown compound used in this study was presented

    CdSe Quantum Dot (QD)-Induced Morphological and Functional Impairments to Liver in Mice

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    Quantum dots (QDs), as unique nanoparticle probes, have been used in in vivo fluorescence imaging such as cancers. Due to the novel characteristics in fluorescence, QDs represent a family of promising substances to be used in experimental and clinical imaging. Thus far, the toxicity and harmful health effects from exposure (including environmental exposure) to QDs are not recognized, but are largely concerned by the public. To assess the biological effects of QDs, we established a mouse model of acute and chronic exposure to QDs. Results from the present study suggested that QD particles could readily spread into various organs, and liver was the major organ for QD accumulation in mice from both the acute and chronic exposure. QDs caused significant impairments to livers from mice with both acute and chronic QD exposure as reflected by morphological alternation to the hepatic lobules and increased oxidative stress. Moreover, QDs remarkably induced the production of intracellular reactive oxygen species (ROS) along with cytotoxicity, as characterized by a significant increase of the malondialdehyde (MDA) level within hepatocytes. However, the increase of the MDA level in response to QD treatment could be partially blunted by the pre-treatment of cells with beta-mercaptoethanol (β-ME). These data suggested ROS played a crucial role in causing oxidative stress-associated cellular damage from QD exposure; nevertheless other unidentified mediators might also be involved in QD-mediated cellular impairments. Importantly, we demonstrated that the hepatoxicity caused by QDs in vivo and in vitro was much greater than that induced by cadmium ions at a similar or even a higher dose. Taken together, the mechanism underlying QD-mediated biological influences might derive from the toxicity of QD particles themselves, and from free cadmium ions liberated from QDs as well

    Another beauty of analytical chemistry: chemical analysis of inorganic pigments of art and archaeological objects

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    [EN] This lecture text shows what fascinating tasks analytical chemists face in Art Conservation and Archaeology, and it is hoped that students reading it will realize that passions for science, arts or history are by no means mutually exclusive. This study describes the main analytical techniques used since the eighteenth century, and in particular, the instrumental techniques developed throughout the last century for analyzing pigments and inorganic materials, in general, which are found in cultural artefacts, such as artworks and archaeological remains. The lecture starts with a historical review on the use of analytical methods for the analysis of pigments from archaeological and art objects. Three different periods can be distinguished in the history of the application of the Analytical Chemistry in Archaeometrical and Art Conservation studies: (a) the "Formation'' period (eighteenth century1930), (b) the "Maturing'' period (1930-1970), and (c) the "Expansion'' period (1970-nowadays). A classification of analytical methods specifically established in the fields of Archaeometry and Conservation Science is also provided. After this, some sections are devoted to the description of a number of analytical techniques, which are most commonly used in routine analysis of pigments from cultural heritage. Each instrumental section gives the fundamentals of the instrumental technique, together with relevant analytical data and examples of applications.Financial support is gratefully acknowledged from Spanish ‘‘I+D+I MINECO’’ projects CTQ2011-28079-CO3-01 and CTQ2014-53736-C3-1-P supported by ERDEF funds.Domenech Carbo, MT.; Osete Cortina, L. (2016). Another beauty of analytical chemistry: chemical analysis of inorganic pigments of art and archaeological objects. ChemTexts. 2:1-50. https://doi.org/10.1007/s40828-016-0033-5S1502Wilks H (ed) (1987) Science for conservators: a conservation science teaching series. The Conservation Unit Museums and Galleries Commission, LondonSan Andrés Moya M, Viña Ferrer S (2004) Fundamentos de química y física para la conservación y restauración. Síntesis, MadridDoménech-Carbó MT (2013) Principios físico-químicos de los materiales integrantes de los bienes culturales, Universitat Politècnica de ValènciaMills JS, White R (1987) The organic chemistry of museum objects. Butterworths, London, pp 141–159Matteini M, Moles A (1991) La Quimica nel Restauro. I materiali dell’arte pittorica. Nardini, FirenzeGomez MA (1998) La Restauración. Examen científico aplicado a la conservación de obras de arte. Cátedra, MadridTaft WS Jr, Mayer JW (2000) The science of paintings. Springer, New YorkAllen RO (ed) (1989) Archaeological chemistry IV; Advances in chemistry. American Chemical Society, Washington, DCAitken MJ (1990) Science-based dating in archaeology. Longman Archaeology Series, New YorkCiliberto E, Spoto G (eds) (2000) Modern analytical methods in art and archaeology. Wiley, New YorkMatteini M, Moles A (1986) Sciencia e Restauro. Metodi di Indagine, 2nd edn. Nardini, FirenzeOdegaard N, Carroll S, Zimmt W (2000) Material characterization tests for objects of art and archaeology. Archetype Publications, LondonDerrick MR, Stulik DC, Landry MJ (1999) Infrared spectroscopy in conservation science. Getty Conservation Institute, Los AngelesDoménech-Carbó A, Doménech-Carbó MT, Costa V (2009) Electrochemical methods in archaeometry, conservation and restoration. In: Scholz F (ed) Series: Monographs in electrochemistry. Springer, BerlinEdwards HGM, Chalmers JM (eds) (2005) Raman spectroscopy in archaeology and art history. The Royal Society of Chemistry, CambridgeLahanier C (1991) Scientific methods applied to the study of art objects. Mikrochim Acta II:245–254Bitossi G, Giorgi R, Salvadori BM, Dei L (2005) Spectroscopic techniques in cultural heritage conservation: a survey. Appl Spectrosc Rev 40:187–228Odlyha M (2000) Special feature: preservation of cultural heritage. The application of thermal analysis and other advanced analytical techniques to cultural objects. Thermochim Acta 365Feature Special (2003) Archaeometry. Meas Sci Technol 14:1487–1630Aitken MJ (1961) Physics and archaeology. Interscience, New YorkOlin JS (ed) (1982) Future directions in archaeometry. A round table. Smithsonian Institution Press, Washington, DCTownsend JH (2006) What is conservation science? Macromol Symp 238:1–10Nadolny J (2003) The first century of published scientific analyses of the materials of historical painting and polychromy, circa 1780–1880. Rev Conserv 4:39–51Montero Ruiz I, Garcia Heras M, López-Romero E (2007) Arqueometría: cambios y tendencias actuales. Trabajos de Prehistoria 64:23–40Fernandes Vieira G, Sias Coelho LJ (2011) Arqueometría: Mirada histórica de una ciencia en desarrollo. Revista CPC 13:107–133Rees-Jones SG (1990) Early experiments in pigment analysis. Stud Conserv 35:93–101Allen RO (1989) The role of the chemists in archaeological studies. In: Allen RO (ed) Archaeological chemistry IV. Advances in chemistry. American Chemical Society, Washington DC, pp 1–17Plesters J (1956) Cross-sections and chemical analysis of paint samples. Stud Conserv 2:110–157 and references thereinGilberg M (1987) Friedrich Rathgen: the father of modern archaeological conservation. J Am Inst Conserv 26:105–120Olin JS, Salmon ME, Olin CH (1969) Investigations of historical objects utilizing spectroscopy and other optical methods. Appl Optics 8:29–39Feller RL (1954) Dammar and mastic infrared analysis. Science 120:1069–1070Hall ET (1963) Methods of analysis (physical and microchemical) applied to paintings and antiquities. In: Thomson G (ed) Recent advances in conservation. Butterworths, London, pp 29–32Feigl F, Anger V (1972) Spot tests in inorganic analysis, 6th English edition, translated by Oesper RE. Elsevier, AmsterdamLocke DC, Riley OH (1970) Chemical analysis of paint samples using the Weisz ring oven technique. Stud Conserv 15:94–101Mairinger F, Schreiner M (1986) Analysis of supports, grounds and pigments. In: van Schoute R, Verougstracte-Marcq H (eds) PACT 13, Xth Anniversary Meeting of PACT Group. Louvain-la Neuve, pp 171–183 (and references therein)Vandenabeele P, Edwards HGM (2005) Overview: Raman spectrometry of artefacts. In: Edwards HGM, Chalmers JM (eds) Raman spectroscopy in archaeology and art history. The Royal Society of Chemistry, Cambridge, pp 169–178Tykot RH (2004) Scientific methods and applications to archaeological provenance studies. In: Proceedings of the International School of Physics “Enrico Fermi”. IOS Press, Amsterdam, pp 407–432Doménech-Carbó A, Doménech-Carbó MT, Valle-Algarra FM, Domine ME, Osete-Cortina L (2013) On the dehydroindigo contribution to Maya Blue. J Mat Sci 48:7171–7183Lovric M, Scholz F (1997) A model for the propagation of a redox reaction through microcrystals. J Solid State Electrochem 1:108–113Fitzgerald AG, Storey BE, Fabian D (1993) Quantitative microbeam analysis. Scottish Universities Sumer School in Physics and Institute of Physics Publishing, BristolDoménech-Carbó A (2015) Dating: an analytical task. ChemTexts 1:5Mairinger F, Schreiner M (1982) New methods of chemical analysis-a tool for the conservator. Science and Technology in the service of conservation, IIC, London, pp 5–13Malissa H, Benedetti-Pichler AA (1958) Anorganische qualitative Mikroanalyse. Springer, New YorkTertian R, Claisse F (1982) Principles of quantitative X-ray fluorescence analysis. Heyden, LondonMantler M, Schreiner M (2000) X-ray fluorescence spectrometry in art and archaeology. X-Ray Spectrom 29:3–17Scholz F (2015) Voltammetric techniques of analysis: the essentials. ChemTexts 1:17Inzelt G (2014) Crossing the bridge between thermodynamics and electrochemistry. From the potential of the cell reaction to the electrode potential. ChemTexts 1:2Milchev A (2016) Nucleation phenomena in electrochemical systems: thermodynamic concepts. ChemTexts 2:2Milchev A (2016) Nucleation phenomena in electrochemical systems: kinetic models. ChemTexts 2:4Seeber R, Zanardi C, Inzelt G (2015) Links between electrochemical thermodynamics and kinetics. ChemTexts 1:18Feist M (2015) Thermal analysis: basics, applications, and benefit. ChemTexts 1:8Stoiber RE, Morse SA (1994) Crystal identification with the polarizing microscope. Springer, BerlinGoldstein JI, Newbury DE, Echlin P, Joy DC, Lyman CE, Echlin P, Lifshin E, Sawyer L, Michael JR (2003) Scanning electron microscopy and X-ray microanalysis. Plenum Press, New YorkDoménech-Carbó A, Doménech-Carbó MT, Más-Barberá X (2007) Identification of lead pigments in nanosamples from ancient paintings and polychromed sculptures using voltammetry of nanoparticles/atomic force microscopy. Talanta 71:1569–1579Reedy TJ, Reedy ChL (1988) Statistical analysis in art conservation research. The Getty Conservation Institute, Los AngelesEastaugh N, Walsh V, Chaplin T, Siddall R (2004) Pigment compendium, optical microscopy of historical pigments. Elsevier, OxfordFeller RL, Bayard M (1986) Terminology and procedures used in the systematic examination of pigment particles with polarizing microscope. In: Feller RL (ed) Artists’ pigment. A handbook of their history and characteristics, vol 1. National Gallery of Art, Washington, pp 285–298Feller RL (ed) (1986) Artists’ pigment. A handbook of their history and characteristics, vol 1. National Gallery of Art, WashingtonRoy A (ed) (1993) Artists’ pigments. A handbook of their history and characteristics, vol 2. National Gallery of Art, WashingtonFitzHugh EW (ed) (1997) Artists’ pigments. A handbook of their history and characteristics, vol 3. National Gallery of Art, WashingtonBerrie BH (ed) (2007) Artists’ pigment. A handbook of their history and characteristics, vol 4. National Gallery of Art, WashingtonHaynes WN (ed) (2015) CRC handbook for physics and chemistry, 96th edn. Taylor and Francis Group, UKFiedler I, Bayard MA (1986) Cadmium yellows, oranges and reds. In: Feller RL (ed) Artists’ pigment. A handbook of their history and characteristics, vol 1. National Gallery of Art, Washington, pp 65–108Domenech-Carbó MT, de Agredos Vazquez, Pascual ML, Osete-Cortina L, Domenech A, Guasch-Ferré N, Manzanilla LR, Vidal C (2012) Characterization of Pre-hispanic cosmetics found in a burial of the ancient city of Teotihuacan (Mexico). J Archaeol Sci 39:1043–1062Mühlethaler B, Thissen J (1993) Smalt. In: Roy A (ed) Artists’ pigments. A handbook of their history and characteristics, vol 2. National Gallery of Art, Washington, pp 113–130Musumarra G, Fichera M (1998) Chemometrics and cultural heritage. Chemometr Intell Lab Syst 44:363–372Hochleitner B, Schreiner M, Drakopoulos M, Snigireva I, Snigirev A (2005) Analysis of paint layers by light microscopy, scanning electron microscopy and synchrotron induced X-ray micro-diffraction. In: Van Grieken R, Janssens K (eds) Cultural heritage conservation and environment impact assessment by non-destructive testing and micro-analysis. AA Balkema Publishers, London, pp 171–182Švarcová S, Kočí E, Bezdička P, Hradil D, Hradilová J (2010) Evaluation of laboratory powder X-ray micro-diffraction for applications in the fields of cultural heritage and forensic science. Anal Bioanal Chem 398:1061–1076Van de Voorde L, Vekemans B, Verhaeven E, Tack P, DeWolf R, Garrevoet J, Vandenabeele P, Vincze L (2015) Analytical characterization of a new mobile X-ray fluorescence and X-ray diffraction instrument combined with a pigment identification case study. Spectrochim Acta B 110:14–19Hochleitner B, Desnica V, Mantler M, Schreiner M (2003) Historical pigments: a collection analyzed with X-ray diffraction analysis and X-ray fluorescence analysis in order to create a database. Spectrochim Acta B 58:641–649Middleton PS, Ospitali F, Di Lonardo F (2005) Case study: painters and decorators: Raman spectroscopic studies of five Romano-British villas and the Domus Coiedii at Suasa, Italy. In: Edwards HGM, Chalmers JM (eds) Raman spectroscopy in archaeology and art history. The Royal Society of Chemistry, Cambridge, pp 97–120Helwig K (1993) Iron oxide pigments: natural and synthetic. In: Roy A (ed) Artists’ pigments. A handbook of their history and characteristics, vol 2. National Gallery of Art, Washington, pp 39–95Silva CE, Silva LP, Edwards HGM, de Oliveira LFC (2006) Diffuse reflection FTIR spectral database of dyes and pigments. Anal Bioanal Chem 386:2183–2191Hummel DO (ed) (1985) Atlas of polymer and plastic analysis, vol 1, Polymers, structures and spectra. Hanser VCH, Münichhttp://www.irug.org (consulted: 1 Feb 2016)http://www.ehu.es/udps/database/database.html (consulted: 1 Feb 2016)Burgio L, Clark RJH (2001) Library of FT-Raman spectra of pigments, minerals, pigment media and varnishes, and supplement to existing library of Raman spectra of pigments with visible excitation. Spectrochim Acta A 57:1491–1521http://www.chem.ucl.ac.uk/resources/raman/speclib.html (consulted: 1 Feb 2016)Madariaga JM, Bersani D (2012) Special feature: Raman spectroscopy in art and archaeology. J Raman Spectrosc 43(11):1523–1844http://minerals.gps.caltech.edu/ (consulted: 1 Feb 2016)http://www.rruff.info (consulted: 1 Feb 2016)Frost RL, Martens WN, Rintoul L, Mahmutagic E, Kloprogge JT (2002) J Raman Spectrosc 33:252–259Smith D (2005) Overwiew: jewellery and precious stones. In: Edwards HGM, Chalmers JM (eds) Raman spectroscopy in archaeology and art history. The Royal Society of Chemistry, Cambridge, pp 335–378Weiner S, Bar-Yosef O (1990) States of preservation of bones from prehistoric sites in the Near East: a survey. J Archaeol Sci 17:187–196Chu V, Regev L, Weiner S, Boaretto E (2008) Differentiating between anthropogenic calcite in plaster, ash and natural calcite using infrared spectroscopy: implications in archaeology. J Archaeol Sci 35:905–911Beniash E, Aizenberg J, Addadi L, Weiner S (1997) Amorphous calcium carbonate transforms into calcite during sea-urchin larval spicule growth. Proc R Soc Lond Ser B 264:461–465Regev L, Poduska KM, Addadi L, Weiner S, Boaretto E (2010) Distinguishing between calcites formed by different mechanisms using infrared spectrometry: archaeological applications. J Archaeol Sci 37:3022–3029Farmer C (ed) (1974) The infrared spectra of mineral, Monograph 4. Mineralogical Society, LondonMadejová J, Kečkéš J, Pálková H, Komadel P (2002) Identification of components in smectite/kaolinite mixtures. Clay Miner 37:377–388Šucha V, Środoń J, Clauer N, Elsass F, Eberl DD, Kraus I, Madejová J (2001) Weathering of smectite and illite–smectite under temperate climatic conditions. Clay Miner 36:403–419Doménech-Carbó A, Doménech-Carbó MT, López-López F, Valle-Algarra FM, Osete-Cortina L, Arcos-Von Haartman E (2013) Electrochemical characterization of egyptian blue pigment in wall paintings using the voltammetry of microparticles methodology. Electroanalysis 25:2621–2630Doménech-Carbó MT, Edwards HGM, Doménech-Carbó A, del Hoyo-Meléndez JM, de la Cruz-Cañizares J (2012) An authentication case study: Antonio Palomino vs. Vicente Guillo paintings in the vaulted ceiling of the Sant Joan del Mercat church (Valencia, Spain). J Raman Spectrosc 43:1250–1259Lovric M, Scholz F (1999) A model for the coupled transport of ions and electrons in redox conductive microcrystals. J Solid State Electrochem 3:172–175Oldham KB (1998) Voltammetry at a three phase junction. J Solid State Electrochem 2:367–377Doménech A, Doménech-Carbó MT, Gimeno-Adelantado JV, Bosch-Reig F, Saurí-Peris MC, Sánchez-Ramos S (2001) Electrochemical identification of iron oxide pigments (earths) from pictorial microsamples attached to graphite/polyester composite electrodes. Analyst 126:1764–1772Doménech A, Doménech-Carbó MT, Moya-Moreno MCM, Gimeno-Adelantado JV, Bosch-Reig F (2000) Identification of inorganic pigments from paintings and polychromed sculptures immobilized into polymer film electrodes by stripping differential pulse voltammetry. Anal Chim Acta 407:275–289Doménech-Carbó A, Doménech-Carbó MT, Valle-Algarra FM, Gimeno-Adelantado JV, Osete-Cortina L, Bosch-Reig F (2016) On-line database of voltammetric data of immobilized particles for identifying pigments and minerals in archaeometry, conservation and restoration (ELCHER database). Anal Chim Acta 927:1–12http://www.elcher.info (consulted: 1 July 2016)Scholz F, Doménech-Carbó A (2010) Special feature: electrochemistry for conservation science. J Solid State Electrochem 14Domenech-Carbó A, Domenech-Carbó MT, Edwards HGM (2007) Identification of earth pigment by hierarchical cluster applied to solid state voltammetry. Application to a severely damaged frescoes. Electroanalysis 19:1890–1900Domenech-Carbó A, Domenech-Carbó MT, Vázquez de Agredos-Pascual ML (2006) Dehydroindigo: a new piece into the Maya Blue puzzle from the voltammetry of microparticles approach. J Phys Chem B 110:6027–6039Doménech-Carbó A, Doménech-Carbó MT, Vázquez de Agredos-Pascual ML (2007) Chemometric study of Maya Blue from the voltammetry of microparticles approach. Anal Chem 79:2812–2821Doménech-Carbó A, Doménech-Carbó MT, Vázquez de Agredos-Pascual ML (2011) From Maya Blue to ‘Maya Yellow’: a connection between ancient nanostructured materials from the voltammetry of microparticles. Angew Chem Int Edit 50:5741–5744Doménech-Carbó A, Doménech-Carbó MT, Vidal-Lorenzo C, Vázquez de Agredos-Pascual ML (2012) Insights into the Maya Blue Technology: greenish pellets from the ancient city of La Blanca. Angew Chem Int Ed 51:700–703Doménech-Carbó A, Doménech-Carbó MT, Osete-Cortina L, Montoya N (2012) Application of solid-state electrochemistry techniques to polyfunctional organic-inorganic hybrid materials: the Maya Blue problem. Micropor Mesopor Mater 166:123–130Doménech-Carbó MT, Osete-Cortina L, Doménech-Carbó A, Vázquez de Agredos-Pascual ML, Vidal-Lorenzo C (2014) Identification of indigoid compounds present in archaeological Maya blue by pyrolysis-silylation-gas chromatography–mass spectrometry. J Anal Appl Pyrol 105:355–36

    Whole Exome Sequencing of Patients with Steroid-Resistant Nephrotic Syndrome

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    BACKGROUND AND OBJECTIVES: Steroid-resistant nephrotic syndrome overwhelmingly progresses to ESRD. More than 30 monogenic genes have been identified to cause steroid-resistant nephrotic syndrome. We previously detected causative mutations using targeted panel sequencing in 30% of patients with steroid-resistant nephrotic syndrome. Panel sequencing has a number of limitations when compared with whole exome sequencing. We employed whole exome sequencing to detect monogenic causes of steroid-resistant nephrotic syndrome in an international cohort of 300 families. DESIGN, SETTING, PARTIIPANTS AND MEASUREMENTS: Three hundred thirty-five individuals with steroid-resistant nephrotic syndrome from 300 families were recruited from April of 1998 to June of 2016. Age of onset was restricted to <25 years of age. Exome data were evaluated for 33 known monogenic steroid-resistant nephrotic syndrome genes. RESULTS: In 74 of 300 families (25%), we identified a causative mutation in one of 20 genes known to cause steroid-resistant nephrotic syndrome. In 11 families (3.7%), we detected a mutation in a gene that causes a phenocopy of steroid-resistant nephrotic syndrome. This is consistent with our previously published identification of mutations using a panel approach. We detected a causative mutation in a known steroid-resistant nephrotic syndrome gene in 38% of consanguineous families and in 13% of nonconsanguineous families, and 48% of children with congenital nephrotic syndrome. A total of 68 different mutations were detected in 20 of 33 steroid-resistant nephrotic syndrome genes. Fifteen of these mutations were novel. NPHS1, PLCE1, NPHS2, and SMARCAL1 were the most common genes in which we detected a mutation. In another 28% of families, we detected mutations in one or more candidate genes for steroid-resistant nephrotic syndrome. CONCLUSIONS: Whole exome sequencing is a sensitive approach toward diagnosis of monogenic causes of steroid-resistant nephrotic syndrome. A molecular genetic diagnosis of steroid-resistant nephrotic syndrome may have important consequences for the management of treatment and kidney transplantation in steroid-resistant nephrotic syndrome

    Cell tracking in cardiac repair: what to image and how to image

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    Stem cell therapies hold the great promise and interest for cardiac regeneration among scientists, clinicians and patients. However, advancement and distillation of a standard treatment regimen are not yet finalised. Into this breach step recent developments in the imaging biosciences. Thus far, these technical and protocol refinements have played a critical role not only in the evaluation of the recovery of cardiac function but also in providing important insights into the mechanism of action of stem cells. Molecular imaging, in its many forms, has rapidly become a necessary tool for the validation and optimisation of stem cell engrafting strategies in preclinical studies. These include a suite of radionuclide, magnetic resonance and optical imaging strategies to evaluate non-invasively the fate of transplanted cells. In this review, we highlight the state-of-the-art of the various imaging techniques for cardiac stem cell presenting the strengths and limitations of each approach, with a particular focus on clinical applicability

    Nanoparticles for Applications in Cellular Imaging

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    In the following review we discuss several types of nanoparticles (such as TiO2, quantum dots, and gold nanoparticles) and their impact on the ability to image biological components in fixed cells. The review also discusses factors influencing nanoparticle imaging and uptake in live cells in vitro. Due to their unique size-dependent properties nanoparticles offer numerous advantages over traditional dyes and proteins. For example, the photostability, narrow emission peak, and ability to rationally modify both the size and surface chemistry of Quantum Dots allow for simultaneous analyses of multiple targets within the same cell. On the other hand, the surface characteristics of nanometer sized TiO2allow efficient conjugation to nucleic acids which enables their retention in specific subcellular compartments. We discuss cellular uptake mechanisms for the internalization of nanoparticles and studies showing the influence of nanoparticle size and charge and the cell type targeted on nanoparticle uptake. The predominant nanoparticle uptake mechanisms include clathrin-dependent mechanisms, macropinocytosis, and phagocytosis

    Interim 2017/18 influenza seasonal vaccine effectiveness: Combined results from five European studies

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    Between September 2017 and February 2018, influenza A(H1N1)pdm09, A(H3N2) and B viruses (mainly B/Yamagata, not included in 2017/18 trivalent vaccines) co-circulated in Europe. Interim results from five European studies indicate that, in all age groups, 2017/18 influenza vaccine effectiveness was 25 to 52% against any influenza, 55 to 68% against influenza A(H1N1)pdm09, -42 to 7% against influenza A(H3N2) and 36 to 54% against influenza B. 2017/18 influenza vaccine should be promoted where influenza still circulates
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