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Ein neues Konzept für die Anwendung von einwandigen Kohlenstoffnanoröhren für die pH-Sensorik

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Book Series: Schriftenreihe des Instituts für Angewandte Informatik - Automatisierungstechnik, Karlsruher Institut für Technologie ISSN: 16145267 ISBN: 9783866446410 Year: Volume: 36 Pages: XX, 197 p. DOI: 10.5445/KSP/1000022233 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:01:59
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Einwandige Kohlenstoffnanoröhren (SWCNTs) gelten aufgrund ihrer hohen Ladungsträgermobilität, des hohen Oberfläche-Volumen-Verhältnisses und der Tatsache, dass all ihre Atome mit der Umgebung wechselwirken, als hoch interessant für die Sensorik. Hier wird ein neues Konzept für die Messung des pH-Wertes, der als wichtigster Parameter der Flüssiganalytik gilt, auf Basis von SWCNTs vorgestellt und anhand der Charakterisierung der hergestellten Sensoren die Funktionsfähigkeit nachgewiesen.

Ein neues Konzept zur Diagnose elektrochemischer Sensoren am Beispiel von pH-Glaselektroden

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Book Series: Schriftenreihe des Instituts für Angewandte Informatik - Automatisierungstechnik, Karlsruher Institut für Technologie ISSN: 16145267 ISBN: 9783866447059 Year: Volume: 39 Pages: XXII, 192 p. DOI: 10.5445/KSP/1000023598 Language: GERMAN
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:02:02
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Unternehmen der Prozessindustrie verlangen zunehmend Sensoren mit einer integrierten Diagnosefunktionaliät, die Informationen über den technischen Zustand der eingesetzten Betriebsmittel gibt.Ziel der Arbeit ist es, am Beispiel von pH-Glaselektroden ein neues Konzept zu entwickeln, das es möglich macht, den technischen Zustand von elektrochemischen Sensoren abzubilden.Anhand von Daten aus Laborversuchen sowie aus industriellen Anwendungen wird der Nachweis der Funktionsfähigkeit erbracht.

Storia di un dottorato: storia medievale nell'Università di Firenze

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Book Series: Scuole di dottorato ISBN: 8884531780 Year: DOI: 10.26530/OAPEN_345475 Language: Italian
Publisher: Firenze University Press
Subject: History
Added to DOAB on : 2011-11-04 00:00:00
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The PhD course in Mediaeval History of the University of Florence is one of the oldest in the Italian university circuit. Founded in 1983 by Girolamo Arnaldi, Elio Conti and Raoul Manselli, all the cycles of the courses were launched, achieving results of the greatest significance in the sphere of research. Over the years, about sixty young students and a couple of dozen teachers have given shape to a human and intellectual experience based on exchange and the acceptance of different points of view. Traced out in this book is a brief history of the first twenty years, rendering account of the activities fostered and the research carried out, and providing the scientific and bibliographic profiles of each member.

Tumor Hypoxia: Impact in Tumorigenesis, Diagnosis, Prognosis and Therapeutics

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889450640 Year: Pages: 113 DOI: 10.3389/978-2-88945-064-0 Language: English
Publisher: Frontiers Media SA
Subject: Biology --- Science (General) --- Oncology --- Medicine (General)
Added to DOAB on : 2017-07-06 13:27:36
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Hypoxic regions have been identified within tumors and its presence has been linked to malignant progression, metastasis, resistance to therapy, and poor clinical outcomes following treatment. Acute and chronic hypoxia are integral components of tumor microenvironment and conduce to metabolic adaptations of tumor cells leading to genetic instability, intratumor heterogeneity and malignant progression. On the success of our fight against cancer, the continued adaptability of tumors to their microenvironmental stresses, such as hypoxia, must be considered. Tumor cells are endowed with a very high plasticity and capacity to adapt. It is our challenge to find populations and conditions of the tumor microenvironment germane for target success. Interdisciplinary work will be the key for achievement of these goals. This e-book is a compendium of original reports and review articles contributed by world-class experts in the field of tumor hypoxia. This material will be useful to foster discussion and increase understanding of the involvement of hypoxia in tumorigenesis, biomarker development, and therapeutics.Hypoxic regions have been identified within tumors and its presence has been linked to malignant progression, metastasis, resistance to therapy, and poor clinical outcomes following treatment. Acute and chronic hypoxia are integral components of tumor microenvironment and conduce to metabolic adaptations of tumor cells leading to genetic instability, intratumor heterogeneity and malignant progression. On the success of our fight against cancer, the continued adaptability of tumors to their microenvironmental stresses, such as hypoxia, must be considered. Tumor cells are endowed with a very high plasticity and capacity to adapt. It is our challenge to find populations and conditions of the tumor microenvironment germane for target success. Interdisciplinary work will be the key for achievement of these goals. This e-book is a compendium of original reports and review articles contributed by world-class experts in the field of tumor hypoxia. This material will be useful to foster discussion and increase understanding of the involvement of hypoxia in tumorigenesis, biomarker development, and therapeutics.

Keywords

hypoxia --- tumor --- microenvironment --- HIF --- pH --- stress --- Stem Cells --- Leukemia --- biomarkers --- therapy

Stimuli-Responsive Gels

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ISBN: 9783038972105 9783038972112 Year: Pages: 288 DOI: 10.3390/books978-3-03897-211-2 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Chemistry (General) --- Chemical Technology
Added to DOAB on : 2018-10-11 10:12:55
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ca. 200 words; this text will present the book in all promotional forms (e.g. flyers). Please describe the book in straightforward and consumer-friendly terms.[Although the technological and scientific importance of functional polymers have been well established over the last few decades, the most recent focus that has attracted much attention concerns stimuli-responsive polymer gels. These materials are of particular interest due to their abilities to respond to internal and/or external chemo-physical stimuli. Aside from the scientific challenges of designing stimuli-responsive polymer gels, the main technological interests concern numerous applications, ranging from catalysis in microsystem technology and chemo-mechanical actuators to sensors. This Special Issue includes seventeen papers covering a wide range of subjects including thermo- and pH-responsive hydrogels, functionalized materials, supramolecular stimuli-responsive structures, composite hydrogels, sensors, and biomedical applications. Together, these contributions not only provide an excellent overview of the current state-of-the-art in the field but also point out exciting challenges and opportunities for future work. In a number of reviews the most recent findings on “Stimuli-Responsive Gels” are compiled in this book supplemented by original contributions.

Fungal Pathogenesis in Humans: The Growing Threat

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ISBN: 9783038979005 / 9783038979012 Year: Pages: 232 DOI: 10.3390/books978-3-03897-901-2 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology --- Genetics
Added to DOAB on : 2019-06-26 08:44:06
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Cancer survival rates and successful organ transplantation in patients continues to increase due to improvements in early diagnosis and treatments. Since immuno-suppressive therapies are frequently used, the mortality rate due to secondary infections has become an ever-increasing problem. Opportunistic fungal infections are probably the deadliest threat to these patients due to their difficult early diagnosis, the limited effect of antifungal drugs and the appearance of resistances. In recent years, a considerable effort has been devoted to investigating the role of many virulence traits in the pathogenic outcome of fungal infections. New virulence factors (hypoxia adaptation, CO2 sensing, pH regulation, micronutrient acquisition, secondary metabolites, immunity regulators, etc.) have been reported and their molecular mechanisms of action are being thoroughly investigated. The recent application of gene-editing technologies such as CRISPr-Cas9, has opened a whole new window to the discovery of new fungal virulence factors. Accurate fungal genotyping, Next Generation Sequencing and RNAseq approaches will undoubtedly provide new clues to interpret the plethora of molecular interactions controlling these complex systems. Unraveling their intimate regulatory details will provide insights for a more target-focused search or a rational design of more specific antifungal agents. This Special Issue is show significant discoveries, proofs of concept of new theories or relevant observations in fungal pathogenesis and its regulation.

Carbonic Anhydrases and Metabolism

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ISBN: 9783038978008 9783038978015 Year: Pages: 184 DOI: 10.3390/books978-3-03897-801-5 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology
Added to DOAB on : 2019-04-25 16:37:17
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Carbonic anhydrases (CAs; EC 4.2.1.1) are metalloenzymes present in all kingdoms of life, as they equilibrate the reaction between three simple but essential chemical species: CO2, bicarbonate, and protons. Discovered more than 80 years ago, in 1933, these enzymes have been extensively investigated due to the biomedical application of their inhibitors, but also because they are an extraordinary example of convergent evolution, with seven genetically distinct CA families that evolved independently in Bacteria, Archaea, and Eukarya. CAs are also among the most efficient enzymes known in nature, due to the fact that the uncatalyzed hydration of CO2 is a very slow process and the physiological demands for its conversion to ionic, soluble species is very high. Inhibition of the CAs has pharmacological applications in many fields, such as antiglaucoma, anticonvulsant, antiobesity, and anticancer agents/diagnostic tools, but is also emerging for designing anti-infectives, i.e., antifungal, antibacterial, and antiprotozoan agents with a novel mechanism of action. Mitochondrial CAs are implicated in de novo lipogenesis, and thus selective inhibitors of such enzymes may be useful for the development of new antiobesity drugs. As tumor metabolism is diverse compared to that of normal cells, ultimately, relevant contributions on the role of the tumor-associated isoforms CA IX and XII in these phenomena have been published and the two isoforms have been validated as novel antitumor/antimetastatic drug targets, with antibodies and small-molecule inhibitors in various stages of clinical development. CAs also play a crucial role in other metabolic processes connected with urea biosynthesis, gluconeogenesis, and so on, since many carboxylation reactions catalyzed by acetyl-coenzyme A carboxylase or pyruvate carboxylase use bicarbonate, not CO2, as a substrate. In organisms other than mammals, e.g., plants, algae, and cyanobacteria, CAs are involved in photosynthesis, whereas in many parasites (fungi, protozoa), they are involved in the de novo synthesis of important metabolites (lipids, nucleic acids, etc.). The metabolic effects related to interference with CA activity, however, have been scarcely investigated. The present Special Issue of Metabolites aims to fill this gap by presenting the latest developments in the field of CAs and their role in metabolism.

Designing Hydrogels for Controlled Drug Delivery

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ISBN: 9783039283569 / 9783039283576 Year: Pages: 162 DOI: 10.3390/books978-3-03928-357-6 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Medicine (General) --- Therapeutics
Added to DOAB on : 2020-04-07 23:07:08
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The aim of this book is to provide an analysis of the main characteristics and applications of hydrogels. Hydrogels are frequently used for manufacturing contact lenses, hygiene products, tissue engineering scaffolds, drug delivery systems, and wound dressings. These materials are useful in everyday life, so publicizing them in both academic and pharmaceutical fields is essential.

Smart Nanovesicles for Drug Targeting and Delivery

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ISBN: 9783038978947 / 9783038978954 Year: Pages: 198 DOI: 10.3390/books978-3-03897-895-4 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Medicine (General) --- Therapeutics
Added to DOAB on : 2019-06-26 08:44:06
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Nanovesicles are highly-promising systems for the delivery and/or targeting of drugs, biomolecules and contrast agents. Despite the fact that initial studies in this area were performed on phospholipid vesicles, there is an ever-increasing interest in the use of other molecules to obtain smart vesicular carriers focusing on strategies for targeted delivery. These systems can be obtained using newly synthesized smart molecules, or by intelligent design of opportune carriers to achieve specific delivery to the site of action.

Asymmetric and Selective Biocatalysis

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ISBN: 9783038978466 9783038978473 Year: Pages: 154 DOI: 10.3390/books978-3-03897-847-3 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Chemistry (General)
Added to DOAB on : 2019-06-26 09:16:44
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This Issue contains one communication, six articles, and two reviews. The communication from Paola Vitale et al. represents a work where whole cells were used as biocatalysts for the reduction of optically active chloroalkyl arylketones followed by a chemical cyclization to give the desired heterocycles. Among the various whole cells screened (baker’s yeast, Kluyveromyces marxianus CBS 6556, Saccharomyces cerevisiae CBS 7336, Lactobacillus reuteri DSM 20016), baker’s yeast provided the best yields and the highest enantiomeric ratios (95:5) in the bioreduction of the above ketones. In this respect, valuable chiral non-racemic functionalized oxygen-containing heterocycles (e.g., (S)-styrene oxide, (S)-2-phenyloxetane, (S)-2-phenyltetrahydrofuran), amenable to be further elaborated on, can be smoothly and successfully generated from their prochiral precursors. Studies about pure biocatalysts with mechanistical studies, application in different reactions, and new immobilization methods for improving their stability were reported in five different articles. The article by Su-Yan Wang et al. describes the cloning, expression, purification, and characterization of an N-acetylglucosamine 2-epimerase from Pedobacter heparinus (PhGn2E). For this, several N-acylated glucosamine derivatives were chemically synthesized and used to test the substrate specificity of the enzyme. The mechanism of the enzyme was studied by hydrogen/deuterium NMR. The study at the anomeric hydroxyl group and C-2 position of the substrate in the reaction mixture confirmed the epimerization reaction via ring-opening/enolate formation. Site-directed mutagenesis was also used to confirm the proposed mechanism of this interesting enzyme. The article by Forest H. Andrews et al. studies two enzymes, benzoylformate decarboxylase (BFDC) and pyruvate decarboxylase (PDC), which catalyze the non-oxidative decarboxylation of 2-keto acids with different specificity. BFDC from Pseudomonas putida exhibited very limited activity with pyruvate, whereas the PDCs from S. cerevisiae or from Zymomonas mobilis showed virtually no activity with benzoylformate (phenylglyoxylate). After studies using saturation mutagenesis, the BFDC T377L/A460Y variant was obtained, with 10,000-fold increase in pyruvate/benzoylformate. The change was attributed to an improvement in the Km value for pyruvate and a decrease in the kcat value for benzoylformate. The characterization of the new catalyst was performed, providing context for the observed changes in the specificity. The article by Xin Wang et al. compares two types of biocatalysts to produce D-lysine L-lysine in a cascade process catalyzed by two enzymes: racemase from microorganisms that racemize L-lysine to give D,L-lysine and decarboxylase that can be in cells, permeabilized cells, and the isolated enzyme. The comparison between the different forms demonstrated that the isolated enzyme showed the higher decarboxylase activity. Under optimal conditions, 750.7 mmol/L D-lysine was finally obtained from 1710 mmol/L L-lysine after 1 h of racemization reaction and 0.5 h of decarboxylation reaction. D-lysine yield could reach 48.8% with enantiomeric excess (ee) of 99%. In the article by Rivero and Palomo, lipase from Candida rugosa (CRL) was highly stabilized at alkaline pH in the presence of PEG, which permitted its immobilization for the first time by multipoint covalent attachment on different aldehyde-activated matrices. Different covalent immobilized preparation of the enzyme was successfully obtained. The thermal and solvent stability was highly increased by this treatment, and the novel catalysts showed high regioselectivity in the deprotection of per-O-acetylated nucleosides. The article by Robson Carlos Alnoch et al. describes the protocol and use of a new generation of tailor-made bifunctional supports activated with alkyl groups that allow the immobilization of proteins through the most hydrophobic region of the protein surface and aldehyde groups that allows the covalent immobilization of the previously adsorbed proteins. These supports were especially used in the case of lipase immobilization. The immobilization of a new metagenomic lipase (LipC12) yielded a biocatalyst 3.5-fold more active and 5000-fold more stable than the soluble enzyme. The PEGylated immobilized lipase showed high regioselectivity, producing high yields of the C-3 monodeacetylated product at pH 5.0 and 4 °C. Hybrid catalysts composed of an enzyme and metallic complex are also treated in this Special Issue. The article by Christian Herrero et al. describes the development of the Mn(TpCPP)-Xln10A artificial metalloenzyme, obtained by non-covalent insertion of Mn(III)-meso-tetrakis(p-carboxyphenyl)porphyrin [Mn(TpCPP), 1-Mn] into xylanase 10A from Streptomyces lividans (Xln10A). The complex was found able to catalyze the selective photo-induced oxidation of organic substrates in the presence of [RuII(bpy)3]2+ as a photosensitizer and [CoIII(NH3)5Cl]2+ as a sacrificial electron acceptor, using water as oxygen atom source. The two published reviews describe different subjects with interest in the fields of biocatalysis and mix metallic-biocatalysis, respectively. The review by Anika Scholtissek et al. describes the state-of-the-art regarding ene-reductases from the old yellow enzyme family (OYEs) to catalyze the asymmetric hydrogenation of activated alkenes to produce chiral products with industrial interest. The dependence of OYEs on pyridine nucleotide coenzyme can be avoided by using nicotinamide coenzyme mimetics. In the review, three main classes of OYEs are described and characterized. The review by Yajie Wang and Huimin Zhao highlights some of the recent examples in the past three years that combine transition metal catalysis with enzymatic catalysis. With recent advances in protein engineering, catalyst synthesis, artificial metalloenzymes, and supramolecular assembly, there is great potential to develop more sophisticated tandem chemoenzymatic processes for the synthesis of structurally complex chemicals. In conclusion, these nine publications give an overview of the possibilities of different catalysts, both traditional biocatalysts and hybrids with metals or organometallic complexes to be used in different processes—particularly in synthetic reactions—under very mild reaction conditions.

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