2,663 research outputs found
Capillary electrophoresis with on-line FTIR detection for the separation of proteins
No full textHere we present the on-line hyphenation between capillary electrophoresis and FT-IR [1] applied to the study of the secondary structure of proteins. FT-IR offers the advantage of real-time, non-destructive and molecule-specific detection as compared to UV, LIF or MS. Therefore FT-IR can be employed as a detection method complementary to the above mentioned techniques. The position of the C=O stretch vibration (the so-called amide I band) can be used as an indicator for the secondary structure of a protein. In helical structures the vibration is centered around 1650 cm-1, while in pleated structures it lies around 1635 cm-1.
The main problem when using FT-IR in aqueous solution was overcome by using heavy water (D2O) where the solvent absorption bands are shifted away from the amide I towards lower wavenumbers. The detection was performed in a micro-machined IR transparent flow-cell [1] and checked using a UV detector to ensure that the proteins were separated as detected in the IR spectrum. The proteins separated were myoglobin, a-lactoglobulin and b-lactalbumin (consisting of two isoforms).
The results of the IR analysis agree very well with ATR data taken in water and D2O. The secondary structure given by the spectral data was confirmed by data recorded using X-ray crystallography. Therefore the technique used can be employed to study proteins, interaction between proteins and other analytes and to study misfolding/refolding of proteins
Terahertz pulsed spectroscopy as a new tool for measuring the structuring effect of solutes on water
No full textAbsorption spectra of aqueous solution of "chaotropes" (structure-breaker) and "kosmotropes" (structure maker) have been recorded in the mid-IR and terahertz (THz) spectral region. A different impact of the two groups of solutes on the absorption spectrum of water was found in the recorded THz spectra. A concentration dependent increased absorption across the investigated THz spectral region (0.04 - 2 THz , 1,3 - 66 cm-1 respectively) has been recorded for all studied chaotropic solutions, whereas the opposite has been obtained for kosmotrope containing solutions. In the case of ionic solutes a further increase in absorption towards higher frequencies was measured. The distinction between chaotrope and kosmotrope solutes was, as expected, also possible in the mid-IR spectral region. Depending on the structure forming effect of the solute the OH stretch vibration of the water (around 3400 cm-1) was slightly shifted. A red shift has been observed for solution of kosmotropes, whereas a blue shift was observed in case of solutions containing chaotropes. Compared to the mid-IR spectral region the structure influencing effect of solutes can be more efficiently studied in the THz spectral region, which provides information from interactions between neighboring water molecules
Mid-infrared intracavity quartz-enhanced photoacoustic spectroscopy with pptv - Level sensitivity using a T-shaped custom tuning fork
Full text linkResonant optical power buildup inside a high finesse cavity is exploited to boost the sensitivity in quartz-enhanced photoacoustic spectroscopy (QEPAS) for CO, N₂O and H₂O detection, operating at a wavelength of 4.59 µm. A quartz tuning fork with T-shaped prongs optimized for QEPAS has been employed. Exploiting the high signal-to-noise ratio attainable with this tuning fork together with an optical power amplification of ~100 enabled by efficient optical feedback locking, limits of detection (3σ, 10 s integration) of 260 ppt and 750 ppt for CO and N₂O have been reached
sj-docx-1-asp-10.1177_00037028231206186 - Supplemental material for Chiral Monitoring Across Both Enantiomeric Excess and Concentration Space: Leveraging Quantum Cascade Lasers for Sensitive Vibrational Circular Dichroism Spectroscopy
No full textSupplemental material, sj-docx-1-asp-10.1177_00037028231206186 for Chiral Monitoring Across Both Enantiomeric Excess and Concentration Space: Leveraging Quantum Cascade Lasers for Sensitive Vibrational Circular Dichroism Spectroscopy by Daniel-Ralph Hermann, Georg Ramer, Lisa Riedlsperger and Bernhard Lendl in Applied Spectroscopy</p
Bernhard Karlgren Portrait of A Scholar
No full textThe author draws a portrait of his teacher Bernhard Karlgren (1889-1978), whose research in a variety of fields laid the foundations of Modern Sinology. The work deals with Karlgren's childhood, school years, university studies at Uppsala and St. Petersburg, adventurous sojourn in China, studies in Paris, and academic career at Uppsala and Gothenburg University. This book will help the reader gain insight into the man behind the stern scholar.Intro -- Preface -- 1 Childhood and Schooldays in Jönköping, 1889-1907 -- THE HOME AND THE FAMILY -- LARS OF THE MANOR AND HIS TWO SONS -- THE CLERGYMAN'S DAUGHTER ELLA HASSELBERG AND HER FAMILY -- THE GOOD AND FAITHFUL SERVANT -- THE DIFFICULT YEARS -- BERNHARD: POET, TRANSLATOR, AND DRAMATIST -- THE DIALECT INVESTIGATOR -- 2 Liber Studiosus, 1907-1909 -- STUDIES AT UPPSALA UNIVERSITY -- RUSSIAN WINTER -- 3 The Great Adventure, 1910-1911 -- SAILING IN A SHIP CARRYING GUNPOWDER AS CARGO -- TAIYUAN UNIVERSITY -- THE INDUSTRIOUS DIALECTOLOGIST -- WORRIES ABOUT THE FUTURE -- THE TREASURES OF THE STONE FOREST -- THE FOREIGN CORRESPONDENT -- 4 The Irresolute Strategist, 1912-1914 -- THE INTERLUDE IN LONDON -- AT THE FEET OF CHAVANNES IN PARIS -- 5 The Diligent Correspondent -- THE AVID READER -- THE GREAT QUESTIONS -- SELF-SEARCHING -- 6 The Scholarly Breakthrough -- UPPSALA OR PARIS? -- THE PUBLIC DEFENSE OF THE THESIS -- THE YOUNG LECTURER -- THE STRUGGLE TO MAKE A LIVING -- THE FARSIGHTED PLANNER -- 7 The Gothenburg Years, 1918-1939 -- THE FIRST YEARS AT GOTHENBURG UNIVERSITY -- BACK TO THE FAR EAST -- BACK AT THE TEACHER'S DESK -- THE NARROW CONFINES OF THE SOCIETY OF SCHOLARSHIP -- THE CONFERRING OF DOCTORAL DEGREES IN 1931 -- BERNHARD KARLGREN AND SVEN HEDIN 9 -- THE DEFENDER OF HUMAN RIGHTS -- BERNHARD KARLGREN OUTSIDE THE IVORY TOWER -- 8 Proximitatem Linguae Longinquae Manifestam Fecit -- CHINA'S TRADITIONAL PHILOLOGY -- LINGUISTIC ECHO-SOUNDING -- RIMES AND SOUNDING SIGNS IN ANCIENT CHINA -- SIBLINGS IN FAMILIES OF CHINESE WORDS -- THE BOLD PIONEER -- UNFINISHED INCEPTIONS -- ABC TRAVELS EAST -- 9 Stockholm, 1939-1959: The Legendary Master -- THE EAST ASIAN COLLECTION -- THE MORPHOLOGY AND SYNTAX OF BRONZE DÉCOR -- THE PHILOLOGIST IN HIS ELEMENT -- EXCURSIONS IN CHINESE GRAMMAR -- THE STERN CRITIC -- THE EMINENT POPULARIZERSCHOLAR IN THE SERVICE OF SOCIETY -- DR. BACKMAN, DOCENT SPIRA, AND SENIOR MASTER BRUUN -- A REMARKABLE FAMILY OF BROTHERS AND SISTERS -- THE VENERATED MASTER AND HIS DISCIPLES -- 10 Bernhard Karlgren, Professor Emeritus, 1959-1978 -- BERNHARD KARLGREN AND THE BMFEA -- IN THE LEXICOGRAPHER'S STUDY -- CITIZEN IN THE REPUBLIC OF SCHOLARS -- A List of Works by Bernhard Karlgren in Other Languages than Swedish, Together with Translations into Chinese and Japanese, and a List of His Distinctions and Awards -- ABBREVIATIONS -- Notes -- CHAPTER 1. CHILDHOOD -- CHAPTER 2. LIBER STUDIOSUS -- CHAPTER 3. THE GREAT ADVENTURE -- CHAPTER 4. IRRESOLUTE STRATEGIST -- CHAPTER 5. DILIGENT CORRESPONDENT -- CHAPTER 6. SCHOLARLY BREAKTHROUGH -- CHAPTER 7. GOTHENBURG YEARS -- CHAPTER 8. PROXIMITATEM LINGUAE -- CHAPTER 9. STOCKHOLM, 1939-1959 -- CHAPTER 10. PROFESSOR EMERITUS -- BibliographyThe author draws a portrait of his teacher Bernhard Karlgren (1889-1978), whose research in a variety of fields laid the foundations of Modern Sinology. The work deals with Karlgren's childhood, school years, university studies at Uppsala and St. Petersburg, adventurous sojourn in China, studies in Paris, and academic career at Uppsala and Gothenburg University. This book will help the reader gain insight into the man behind the stern scholar.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
Bernhardi Kellii Hypodidascalus : Darin zu sehen Wie die Schulemeister und Eltern ire angehende Kinder ohn viel schlege durch mannigerlei Richtwege auffs beste/ rechtste und leichtste Teutsch und Lateinisch lesen und schreiben lernen mügen ; Mit einer vorrede und zu End angehengten Ethica scholastica ...
No full textApplication of MCR-ALS to reveal intermediate conformations in the thermally induced α-β transition of poly-L-lysine monitored by FT-IR spectroscopy
Full text linkTemperature-induced conformational transitions of poly-L-lysine were monitored with Fourier-transform infrared (FT-IR) spectroscopy between 10 °C and 70 °C. Chemometric analysis of dynamic IR spectra was performed by multivariate curve analysis–alternating least squares (MCR-ALS) of the amide I′ and amide II′ spectral region. With this approach, the pure spectral and concentration profiles of the conformational transition were obtained. Beside the initial α-helical, the intermediate random coil/extended helices and the final β-sheet structure, an additional intermediate PLL conformation was identified and attributed to a transient β-sheet structure.Fil: Alcaraz, Mirta Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Vienna University of Technology; AustriaFil: Schwaighofer, Andreas. Vienna University of Technology; AustriaFil: Goicoechea, Hector Casimiro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; ArgentinaFil: Lendl, Bernhard. Vienna University of Technology; Austri
Extracting useful information from evolving FTIR data sets using MCR-ALS and 2DCoS: Study of Protein Folding and Intermolecular Interactions in Ionic Liquids
No full textThis paper first reviews the concepts of Two Dimensional Correlation Spectroscopy (2DCoS) and Multivariate Curve Resolution Alternating Least Squares (MCR-ALS) for the analysis of evolving data sets.
In the first example [1] binary mixtures of water in three ionic liquids (IL), 1-ethyl-3-methylimidazolium tetrafluoroborate (emimBF4), 1-butyl-3-methyl-imidazolium tetrafluoroborate (bmimBF4) and 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6) have been studied using FTIR spectroscopy. The region of OH stretching (3800 - 3250 cm-1) has been analyzed. At low concentrations only water monomers interacting with the anion of the ionic liquid exist. At higher water concentrations a second species is observed which has been assigned to a cyclic water dimmer not observed in other solvents.
The second example [2] reports on the proteolysis of BSA using proteinase K studied at 60°C again using FTIR spectroscopy. MCR-ALS applied to infrared measurements allowed the recovery of pure infrared spectra and concentration profiles of the different species involved in the reaction. Special attention was paid to the careful inspection of residuals with the use of Two Dimensional Correlation Spectroscopy. In this way, a heat-induced unfolding step previous to protein hydrolysis was identified. The infrared spectra of the intermediate species showed a more disordered structure than native albumin, being especially noticeable the decrease in -helix conformation. The formation of -sheet aggregates due to heating was detected too.
[1] M. Lopez-Pastor, M.J. Ayora-Cañada, M. Valcárcel, B. Lendl J. Phys. Chem. 110, 10896, 2006.
[2] A. Domínguez-Vidal, M. Saenz-Navajas, M.J. Ayora-Cañada, B. Lendl Anal. Chem. 78, 3257, 2006
ASP892646 Supplemental material - Supplemental material for External Cavity Quantum Cascade Laser-Based Mid-Infrared Dispersion Spectroscopy for Qualitative and Quantitative Analysis of Liquid-Phase Samples
No full textSupplemental material, ASP892646 Supplemental material for External Cavity Quantum Cascade Laser-Based Mid-Infrared Dispersion Spectroscopy for Qualitative and Quantitative Analysis of Liquid-Phase Samples by Stefan Lindner, Jakob Hayden, Andreas Schwaighofer, Tobias Wolflehner, Christian Kristament, María González-Cabrera, Stefan Zlabinger and Bernhard Lendl in Applied Spectroscopy</p
Laser Based Mid-IR Dispersion Spectroscopy of Liquid Samples
No full textNovel laser light sources in the mid-infrared region enable new spectroscopy schemes beyond classical absorption spectroscopy due to the coherent nature of the emitted radiation. We report on a refractive index sensing scheme based on a Mach-Zehnder interferometer and an external-cavity quantum cascade laser that allows rapid acquisition of high-resolution spectra of liquid-phase samples, sensitive to relative refractive index changes down to 10−7. Dispersion spectra of three model proteins in deuterated solution were recorded at concentrations as low as 0.25 mg mL−1. Comparison with Kramers-Kronig-transformed Fourier transform infrared absorbance spectra revealed high conformance, and obtained figures of merit compare well with conventional high-end FTIR spectroscopy [1].
REFERENCES
[1] Alicja Dabrowska, Andreas Schwaighofer, Stefan Lindner, and Bernhard Lendl, Mid-IR refractive index sensor for detecting proteins employing an external cavity quantum cascade laser-based Mach-Zehnder interferometer, Opt. Exp. 28(24), 36632-36642 (2020)
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