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  • 1
    Online-Ressource
    Online-Ressource
    Newark :John Wiley & Sons, Incorporated,
    Schlagwort(e): Biosensor industry. ; Electronic books.
    Materialart: Online-Ressource
    Seiten: 1 online resource (428 pages)
    Ausgabe: 1st ed.
    ISBN: 9783527612260
    DDC: 547
    Sprache: Englisch
    Anmerkung: Chemical Sensors and Biosensors for Medical and Biological Applications -- Contents -- Preface -- 1 Introduction -- 1.1 Chemical Sensors as Alternative Analytical Tools -- 1.2 The Concept of Chemical and Biochemical Sensors -- 1.3 Recognition Processes and Sensor Technology: Milestones -- 1.4 Goals for Future Developments and Trends -- 1.4.1 Trends -- 1.4.2 Miniatuization Nanotechnology -- 1.4.3 In Vivo and In Situ Monitoring -- 1.4.4 The Analytical Laboratory in the 21st Century (Conclusions) -- References -- 2 Chemical and Biochemical Sensors -- 2.1 Classification, Specification, and Nomenclature of Chemical Sensors -- 2 2 Molecular Recognition Processes for Ions and Neutral Species -- 2.2.1 Introduction -- 2.2.2 Molecular Interactions: Tools and Calculations -- 2.2.3 Molecular Recognition of Ions -- 2.2.4 Hydrogen Bonds -- 2.2.5 Molecular Recognition of Enantiomers -- 2.2.6 Molecular Interactions within the Aqueous Medium -- 2.2.7 Catalysis by Enzymes, Enzyme Mimics and Host-Reactands -- 2.2.8 Catalytic Antibodies -- 2.2.9 Multitopic Recognition of Immunological Systems -- 2.2.10 Conclusions and Considerations for Ligand Design -- References -- 3 Controlling Sensor Reactions -- 3.1 Thermodynamically Controlled Sensor Reactions: Reversibility and Thermodynamic Equilibrium -- 3.1.1 The Chemical Potential and the Partition Equilibrium -- 3.1.2 The Recognition and Transduction Process -- 3.1.3 The Electrochemical Potential and the (Potentiometric) Sensor Response -- 3.2 Thermodynamics of Nonequilibria: Diffusion and Steady-State -- 3.3 Rate-Controlled Sensor Reactions: Mediated Enzyme Reactions -- 3.4. Nonthermodynamic Assumptions -- 3.4.1 Activity Versus Concentrations -- 3.4.2 Ionic Strength and Estimates of Activity Coefficients -- 3.4.3 Activity and Concentration of an Electrolyte: IFCC / IUPAC Definitions -- 3.4.4 The Osmotic Coefficient. , 3.4.5 Calibration, Standardization, and Comparisons with Definitive or Reference Procedures -- 3.4.6 The Liquid Junction Potential under Physiological Conditions -- References -- 4 The Artificial Analyte-Selective Membrane Limitations, Technological Precautions and Developments -- 4.1 Introduction -- 4.2 Types of Membranes and Membrane Models -- 4.2.1 The Biological Membrane -- 4.2.2 Artificial Membranes -- 4.3 The Selectivity Coefficient -- 4.4 The Membrane Composition and the Membrane Medium -- 4.4.1 The Influence of the Permittivity and of Plasticizers -- 4.4.2 The Effect of Electron Pair Donor (EPD) and Acceptor (EPA) . Properties of Solvents . Solubilization Properties of the Membrane -- 4.4.3 The Influence of the Aqueous Sample Environment -- 4.4.4 The Influence of the Surface Tension -- 4.4.5 The Effect of Lipophilic Anionic Sites -- 4.4.6 The Effect of the Ligand Concentration -- 4.5 Response Behavior, Sensitivity, and Detection Limit -- 4.6 Lifetime,Lipophilicity, and Immobilization -- 4.7 Interactions by the Biological Matrix and Precautions -- 4.7.1 Biocompatibility -- 4.7.2 Possible Mechanism of Protein Adsorption -- 4.7.3 Influence of Thrombocytes on PVC Solvent Polymeric Membranes -- 4.7.4 The Donnan Potential -- 4.7.5 The Influence of Anticoagulants -- References -- 5 Potentiometric Chemical Sensors and Biological Applications -- 5.1 Principles of Ion-Selective Electrodes -- 5.2 The Symmetric Potentiometric Cell -- 5.2.1 The Asymmetry of ISE Membranes and Reference Electrodes -- 5.2.2 Analysis During Hemodialysis -- 5.2.3 How About Human Whole Blood? -- 5.3 The Magnesium-Selective Electrode -- 5.3.1 Characteristics of the Magnesium Ion -- 5.3.2 Analytical Techniques -- 5.3.3 Natural Carriers -- 5.3.4 Synthetic Carriers -- 5.3.5 Applications -- 5.3.6 Stop-Flow Analysis, the Continuous Flow System. , 5.3.7 Significance of Magnesium-Selective Assays -- 5.4 Microelectrodes for Intracellular Measurements -- 5.4.1 The Nitrite-Selective Microelectrode -- 5.5 Miniaturized pH Probe for Intraluminal Monitoring of Gastric Juice -- 5.6 Chloride-Selective Measurements in Blood Serum and Urine -- References -- 6 Optical Sensors, Optodes -- 6.1 Introduction and Medical Applications -- 6.2 Sensors Based on Intrinsic Optical Effects of the Target Compound -- 6.2.1 Sensors Based on Inherent Optical Characteristics of a Specific analyte -- 6.2.2 Sensors Based on Inherent Optical Characteristics of a Host Responding to Analyte Quantity with an Optical Effect -- 6.3 Sensors Based on a Labeled Host Compound or a Labeled Competitive Analyte -- 6.4 Chemical Sensors Based on a Second Component: "Simon Optodes -- 6.4.1 Chemical Principles of Operation -- 6.4.2 Optode Membranes for Cations -- 6.4.3 Optode Membranes for Anions -- 6.4.4 Optodes for Gases and Neutral Species -- 6.4.5 Principles of Reactions, Thermodynamic Equilibria and Response Functions -- 6.4.6 Medical Assays: Applications to Diluted Plasma -- 6.4.7 Analytical Performance Parameters -- 6.5 The Optical Transduction Process -- 6.5.1 Absorbance Measurements in Transmission Mode -- 6.5.2 Optical Transducing Elements Based on Multiple Internal Reflection(MIRE) -- 6.6 Trend to Miniaturized Integrated Optical Sensors (MIOS) -- 6.7 NIR-Absorbing Dyes -- 6.8 Conclusions: Electrodes versus Optodes, Possibilities of Neutral Substrates -- References -- 7 Data Validation and Interpretation -- 7.1 Introduction: What Does "Data" Mean? What Does "Information" Mean? -- 7.2 The Results of Analytical Tests: Random Numbers or Information Base? -- 7.2.1 Information,Interpretation, and Decision Making -- 7.2.2 What Does Information Mean? -- 7.2.3 The Bayesian Approach. , 7.2.4 General Validation of Clinical Tests and Analytical Results -- 7.2.5 ROC Analysis (Receiver Operating Characteristics) -- 7.2.6 The Likelihood Ratio -- 7.2.7 Multivariate and Clustering Procedure -- 7.3 Goals in Analytical and Clinical Chemistry -- 7.3.1 Analytical Errors and Biological Variation -- 7.3.2 The Biological Scattering Range as the Dynamic Range -- 7.3.3 Accuracy Assessment -- 7.3.4 Conclusions and Recommendations for Planning Diagnostic Tests -- References -- Appendices -- Appendix 1: Milestones in the Development of Chemical and Biochemical Sensors -- Appendix 2: Terminology for the Diagnostic Performance of a Test -- Appendix 3: Biological Setting Points for Electrolytes -- Appendix 4: Allowable Analytical Errors for Electrolytes in Medical Assays -- Appendix 5: Important Cations Physicochemical Characteristics of the Five Biologically -- Appendix 6: Structures and Physical Data of Plasticizers -- Appendix 7: Nomenclature and Molecular Masses of Plasticizers -- Appendix 8: Materials and Methods Used for Preparation of Ion-Selective Electrodes and Synthesis of Hydroxy-Poly(viny1 chloride) -- Appendix 9: Required Logarithmic Selectivity Coefficients for Ion-Selective Electrodes -- Appendix 10: Synthesis and Identity of the Ion-Selective Carriers ETH 7025. ETH 3832 and ETH 5506 used in this Work -- Appendix 11: List of Structures and Selectivity Coefficients of Investigated Magnesium-Selective Ligands -- Appendix 12: IUPAC Units and Statistical Considerations -- Index.
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  • 2
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 61 (1992), S. 1673-1675 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A new type of p-i-n In0.53Ga0.47As photodiode having an optically transparent composite top electrode consisting of a thin semitransparent metal layer and a transparent cadmium tin oxide (CTO) layer was investigated. The composite functions as the n or p contact, an optical window, and an antireflection coating. The transparent contact also prevents shadowing of the active layer by the top electrode, thus allowing greater collection of incident light. Since the CTO contact is nonalloyed, interdiffusion into the i-region is not relevant avoiding an increased dark current. The photodiodes exhibited leakage currents of ≤8 nA and some as low as 23 pA, with reverse breakdown voltages of ≥15–17 V. Responsivity was measured using a 1.55 μm InGaAsP diode laser focused onto an unpassivated 60 μm diam p-i-n photodiode and was ≥0.41 A/W. Photoresponse of the diodes to 3 ps pulses from a Nd:YLF laser (λ=1.047 μm) was 169 and 86 ps for the 60 and 9 μm diodes, respectively. The maximum frequency response of the 9 μm diode is packaging limited, and is expected to have an intrinsic response time of 20–30 ps.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1546-170X
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Medizin
    Notizen: [Auszug] Hypertrophy represents the major physiological response of the heart to adapt to chronically enhanced workload, but is also crucial in the development of heart failure. Although we know of numerous inducers of cardiac hypertrophy, little is known about mechanisms that limit cardiac hypertrophy. ...
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    [s.l.] : Nature Publishing Group
    Nature 424 (2003), S. 831-838 
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] Ultrafast lasers, which generate optical pulses in the picosecond and femtosecond range, have progressed over the past decade from complicated and specialized laboratory systems to compact, reliable instruments. Semiconductor lasers for optical pumping and fast optical saturable absorbers, based on ...
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 65 (1997), S. 113-113 
    ISSN: 1432-0649
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The many remarkable advances that have recently been made in ultrashort pulse generation provide sources with pulse durations as short as 6:5 fs directly out of a Ti:sapphire laser and pulse durations as short as 4:5 fs with external pulse compression. This special issue coincides with and acknowledges a benchmark in ultrashort pulse generation: pulses as short as 6 fs were generated 10 years ago with fiber-grating pulse compression of amplified pulses of a colliding-pulse modelocked dye laser. Today, shorter pulses have been demonstrated for the first time since 1987 and the pulse energies are also substantially higher. Solid-state lasers have been playing a leading role in ultrashort pulse generation since 1990. These lasers also open up new possibilities for practical “real-world” ultrafast sources. Therefore, the second part of this issue is devoted to a typical example of a real-world ultrafast laser, i.e. the diodepumped femtosecond Cr:LiSAF laser, which was modelocked for the first time in 1993. This laser’s pulse duration has been reduced to ≈20 fs and the average output power has been increased to 500 mWwith 100-fs pulses. Another approach for “real-world” ultrafast sources are fiber lasers. Two invited papers provide an overview of the ultrashort pulse performance based on this approach. Most of the papers in this special issue have been invited to provide a full overview of the state-of-the-art capabilities in ultrashort pulse generation today. I amsure that new discoveries are still ahead of us and will continue to drive the strong world-wide research effort. I would like to thank all of the authors who have contributed to this special issue. In addition, I would like to acknowledge the expertise and efforts of the referees, who have provided invaluable feedback on all manuscripts.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Microchimica acta 130 (1998), S. 29-34 
    ISSN: 1436-5073
    Schlagwort(e): humidity-sensitive membrane ; chromoReactand ; ETHT4001
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract 4-(N,N-dioctylamino)-4′-trifluoroacetyl-azobenzene (ETHT 4001), together with the catalyst tridodecylmethylammonium chloride, is dissolved in the hydrophilic polymer polyurethane Tecoflex. The resulting membrane layers show high sensitivity toward water vapour and allow the application of the membranes for humidity measurements. Upon exposure to humid air, the membrane exhibits a decrease in absorbance at a wavelength around 490 nm and an increase at around 430 nm. This signal change is caused by the conversion of the trifluoroacetyl group of the reactand into a diol, thus changing the electron delocalisation of the reactand. The sensor layer exhibits a dynamic range from 1% to 100% RH with highest sensitivity in the 5%–40% RH range. The limit of detection is 0.5% RH. The amount of added catalyst enables the sensitive range to be tailored. The selectivity over ethanol and carbonate is sufficient for the membrane to be used for long-term measurements of air. The change in colour of the humidity-sensitive membrane from red to yellow also means it can be used as an optical test strip.
    Materialart: Digitale Medien
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  • 7
    ISSN: 0009-2940
    Schlagwort(e): Hexacoordination ; Silicon ; Germanium ; Tin ; Phosphinomethanide Ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The group-14 tetrahalides ECl4 (E = Si, Ge, Sn) react with two equivalents of Li[C(PMe2)2(SiMe3)] to give the trans-hexacoordinated complexes Cl2E[C(PMe2)2(SiMe3)]2, which were characterized spectroscopically and by structure determinations in the solid state. The complexes were found to crystallize with or without tetrahydrofuran (THF) molecules, depending on the presence or absence of this solvent. In the case of the silicon complex, the structures of both crystal forms were determined, showing slightly different molecular structures of the complexes in the solid state. Without cocrystallized THF, Cl2Si[C(PMe2)2(SiMe3)]2 has no crystallographically imposed molecular symmetry, while in the presence of THF its crystallographic symmetry is C2h (2/m). The tin and germanium complexes were crystallized either with and without THF molecules, respectively, their crystal structures being isotypic with the respective ones of the silicon complex. In all cases, small amounts of the cis-hexacoordinated isomers were also observed in solution, but only in the case of the silicon complex, it was isolated in pure form. It rearranges to the trans isomer at ambient temperature. trans-Cl2Si[C(PMe2)3]3, trans-Cl2Si[C(PPh2)2(SiMe3)]2 and cis-Me2-Si[C(PMe2)2(SiMe3)]2 were likewise obtained.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
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  • 8
    ISSN: 0009-2940
    Schlagwort(e): Hexacoordination ; Silicon compounds ; Germanium compounds ; Tin compounds ; Phosphanylmethanide ligands ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The dimethyl group-14 element dihalides Me2EX2 (E = Si, Ge, Sn; X = Cl or Br) react with two equivalents of Li[C(P-Me2)2(SiMe3)] to give the cis-hexacoordinated complexes Me2E[C(PMe2)2 (SiMe3)]2 (E = Si: 2a, E = Ge: 2b, E = Sn: 2c), which were characterized spectroscopically and by means of X-ray structure determinations. Whereas 2a and 2b are isotypic and crystallize in the space group P21/c, 2c crystallizes in the space group C2/c with crystallographic C2(2) molecular symmetry. In all cases the diphosphanylmethanide ligands bind in an unisobidentate fashion. For compound 2c, this still can be attributed to the trans influence of the methyl group, but in 2a and 2b clearly borderline cases between hexa- and tetracoordination are found. Compound 2b (E = Ge) is much more on the side of tetracoordination than 2a, thus underlining the importance of small polarity differences for the actual coordination number achieved in compounds with relatively unpolar bonds.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Fresenius' Zeitschrift für analytische Chemie 337 (1990), S. 23-27 
    ISSN: 1618-2650
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 10
    ISSN: 0044-8249
    Schlagwort(e): Chemistry ; General Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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