A Blue Spectral Shift of the Hemoglobin Soret Band Correlates with the Age (Time Since Deposition) of Dried Bloodstains

The effects exerted by fused aromatic rings on the UV-vis spectra of porphyrins are surveyed. Modified porphyrin chromophores with fused benzene, 1,2-naphthalene, 9,10-phenanthrene or phenanthroline rings are surprisingly little affected even when a maximum number of ring fusions are incorporated. Linearly annealed naphtho- or anthraporphyrins show large red shifts to the Q bands but the Soret absorptions are weakened and undergo only minor bathochromic shifts. Fluoranthoporphyrins give multiple bands in the Soret region, but the Q band region is virtually unaffected by this tetracyclic ring system. On the other hand, metal chelates of fluoranthoporphyrins show surprisingly strong bands near 600 nm. Benzothiadiazole rings split and weaken the Soret band, but the Q bands region is unexceptional. However, metal coordination again produces relatively intense bands near 600 nm. The most significant results were obtained for porphyrins with fused acenaphthylene rings. Monoacenaphthoporphyrins (41) have three Soret bands at 387, 431 and 454 nm, and the longest wavelength Q band is shifted to 658 nm. opp-Diacenaphthoporphyrin (43) further shifts these bands with two Soret absorbances at 443 and 470 nm, and an additional strong peak is observed at 692 nm. The metal complexes of these systems also show strong bands between 602 and 656 nm. Still larger effects are produced by tetraacenaphthoporphyrin (47), the dication for which in trifluoroacetic acid (TFA)–chloroform has a Soret absorption at 528 nm. Tetraaryltetraacenaphthoporphyrins (48) are even more red shifted, showing Soret bands between 556 and 570 nm for the free bases and 565 to 588 nm for the related dications. The lead(II) chelate for tetraphenylporphyrin (48a) shows an additional 'hyper' spectral shift that brings the Soret band to 604 nm, and this effect can also be achieved by introducing four meso-phenylethynyl substituents onto the tetraacenaphthoporphyrin nucleus (49). In addition, by combining these two factors for the lead(II) chelate of 49, a record-breaking value for the Soret band of 642 nm can be achieved. Spectral shifts due to ring annelation in porphyrin analogues are also discussed, including those for oxybenziporphyrins, oxypyriporphyrins, carbaporphyrins and sapphyrins.

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The "spectral shift" phenomenon of chloroquine

Archives of Dermatology ◽

10.1001/archderm.93.1.123 ◽

1966 ◽

Vol 93 (1) ◽

pp. 123-128 ◽

Cited By ~ 8

Author(s):

W. M. Sams

Keyword(s):

Spectral Shift

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A Hydrogen Bond Between Linear Tetrapyrrole and Conserved Aspartate Causes the Far-Red Shifted Absorption of Phytochrome Photoreceptors

10.26434/chemrxiv.12278780 ◽

2020 ◽

Author(s):

Egle Maximowitsch ◽

Tatiana Domratcheva

Keyword(s):

Hydrogen Bond ◽

Light Adaptation ◽

Positive Charge ◽

Pyrrole Ring ◽

Md Simulations ◽

Spectral Shift ◽

Specific Domain ◽

Study Guides ◽

Rational Engineering ◽

Tuning Mechanism

Photoswitching of phytochrome photoreceptors between red-absorbing (Pr) and far-red absorbing (Pfr) states triggers light adaptation of plants, bacteria and other organisms. Using quantum chemistry, we elucidate the color-tuning mechanism of phytochromes and identify the origin of the Pfr-state red-shifted spectrum. Spectral variations are explained by resonance interactions of the protonated linear tetrapyrrole chromophore. In particular, hydrogen bonding of pyrrole ring D with the strictly conserved aspartate shifts the positive charge towards ring D thereby inducing the red spectral shift. Our MD simulations demonstrate that formation of the ring D–aspartate hydrogen bond depends on interactions between the chromophore binding domain (CBD) and phytochrome specific domain (PHY). Our study guides rational engineering of fluorescent phytochromes with a far-red shifted spectrum.

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Strong coupling of a plasmonic nanoparticle to a semiconductor nanowire

Nanophotonics ◽

10.1515/nanoph-2021-0214 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Yingying Jin ◽

Liu Yang ◽

Chenxinyu Pan ◽

Zhangxing Shi ◽

Bowen Cui ◽

...

Keyword(s):

Strong Coupling ◽

Coupled System ◽

Resonance Wavelength ◽

Transverse Magnetic ◽

Spectral Shift ◽

Au Nanoparticle ◽

Localized Surface Plasmon ◽

Nanowire Diameter ◽

Plasmonic Nanoparticle ◽

Au Nanosphere

Abstract By placing a single Au nanoparticle on the surface of a cadmium sulfide (CdS) nanowire, we demonstrate strong coupling of localized surface plasmon resonance (LSPR) modes in the nanoparticle and whispering gallery modes (WGMs) in the nanowire. For a 50-nm-diameter Au-nanosphere particle, strong coupling occurs when the nanowire diameter is between 300 and 600 nm, with a mode splitting up to 80 meV. Using a temperature-induced spectral shift of the resonance wavelength, we also observe the anticrossing behavior in the strongly coupled system. In addition, since the Au nanosphere has spherical symmetry, the supported LSPR mode can be selectively coupled with transverse electric (TE) and transverse magnetic (TM) WGMs in the nanowire. The ultracompact strong-coupling system shown here may provide a versatile platform for studying hybrid “photon–plasmon” nanolasers, nonlinear optical devices, and nanosensors.

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Analysis of the ex-vivo transformation of semen, saliva and urine as they dry out using ATR-FTIR spectroscopy and chemometric approach

Scientific Reports ◽

10.1038/s41598-021-91009-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tanurup Das ◽

Abhimanyu Harshey ◽

Ankit Srivastava ◽

Kriti Nigam ◽

Vijay Kumar Yadav ◽

...

Keyword(s):

Phase I ◽

Phase Ii ◽

Ex Vivo ◽

Body Fluids ◽

Biochemical Changes ◽

Partial Least Square ◽

The Body ◽

Slow Phase ◽

Time Since Deposition ◽

Dry Out

AbstractThe ex-vivo biochemical changes of different body fluids also referred as aging of fluids are potential marker for the estimation of Time since deposition. Infrared spectroscopy has great potential to reveal the biochemical changes in these fluids as previously reported by several researchers. The present study is focused to analyze the spectral changes in the ATR-FTIR spectra of three body fluids, commonly encountered in violent crimes i.e., semen, saliva, and urine as they dry out. The whole analytical timeline is divided into relatively slow phase I due to the major contribution of water and faster Phase II due to significant evaporation of water. Two spectral regions i.e., 3200–3400 cm−1 and 1600–1000 cm−1 are the major contributors to the spectra of these fluids. Several peaks in the spectral region between 1600 and 1000 cm−1 showed highly significant regression equation with a higher coefficient of determination values in Phase II in contrary to the slow passing Phase I. Principal component and Partial Least Square Regression analysis are the two chemometric tool used to estimate the time since deposition of the aforesaid fluids as they dry out. Additionally, this study potentially estimates the time since deposition of an offense from the aging of the body fluids at the early stages after its occurrence as well as works as the precursor for further studies on an extended timeframe.

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Design and analysis of a fiber-optic sensing system for shape reconstruction of a minimally invasive surgical needle

Scientific Reports ◽

10.1038/s41598-021-88117-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Aizhan Issatayeva ◽

Aida Amantayeva ◽

Wilfried Blanc ◽

Daniele Tosi ◽

Carlo Molardi

Keyword(s):

Performance Analysis ◽

Minimally Invasive ◽

Optical Fibers ◽

Single Mode ◽

Spectral Shift ◽

Shape Reconstruction ◽

Minimally Invasive Surgical ◽

Working Principle ◽

Doped Fibers ◽

Distributed Measurement

AbstractThis paper presents the performance analysis of the system for real-time reconstruction of the shape of the rigid medical needle used for minimally invasive surgeries. The system is based on four optical fibers glued along the needle at 90 degrees from each other to measure distributed strain along the needle from four different sides. The distributed measurement is achieved by the interrogator which detects the light scattered from each section of the fiber connected to it and calculates the strain exposed to the fiber from the spectral shift of that backscattered light. This working principle has a limitation of discriminating only a single fiber because of the overlap of backscattering light from several fibers. In order to use four sensing fibers, the Scattering-Level Multiplexing (SLMux) methodology is applied. SLMux is based on fibers with different scattering levels: standard single-mode fibers (SMF) and MgO-nanoparticles doped fibers with a 35–40 dB higher scattering power. Doped fibers are used as sensing fibers and SMFs are used to spatially separate one sensing fiber from another by selecting appropriate lengths of SMFs. The system with four fibers allows obtaining two pairs of opposite fibers used to reconstruct the needle shape along two perpendicular axes. The performance analysis is conducted by moving the needle tip from 0 to 1 cm by 0.1 cm to four main directions (corresponding to the locations of fibers) and to four intermediate directions (between neighboring fibers). The system accuracy for small bending (0.1–0.5 cm) is 90$$\%$$ % and for large bending (0.6–1 cm) is approximately 92$$\%$$ % .

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Determination of pseudo-refractive index in self-assembled ligand layers from spectral shift of surface plasmon resonances in colloidal silver nanoplates

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2020-1786 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Pavel Malakhovsky ◽

Dmitry Murausky ◽

Dmitry Guzatov ◽

Sergey Gaponenko ◽

Mikhail Artemyev

Keyword(s):

Refractive Index ◽

Surface Plasmon ◽

Mie Theory ◽

Spectral Shift ◽

Localized Surface Plasmon ◽

Clear Trend ◽

Silver Nanoplates ◽

Assembled Monolayers ◽

Self Assembled

Abstract We examined systematically how self-assembled monolayers (SAMs) of different mercaptoacids affect the spectral shift of the localized surface plasmon resonance in silver nanoplates and nanospheres. We observed a clear trend in the magnitude of a redshift with a molecular length or the SAM thickness within a homologous series of aliphatic mercaptoacids: the thicker shell the stronger the red shift. Using classic Mie theory for plasmonic core-dielectric shell spheres and oblate spheroids we developed the method for determination of a pseudo-refractive index in SAM of different molecules and obtained a good correlation with the reference refractive indices for bulk long-chain aliphatic acids, but only in case of silver nanoplates. Calculations for silver core–shell nanospheres gave overestimated values of refractive index perhaps due to restrictions of Mie theory on the minimum particle size.

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Human Plasma and Recombinant Hemopexins: Heme Binding Revisited

International Journal of Molecular Sciences ◽

10.3390/ijms22031199 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1199

Author(s):

Elena Karnaukhova ◽

Catherine Owczarek ◽

Peter Schmidt ◽

Dominik J. Schaer ◽

Paul W. Buehler

Keyword(s):

Protein S ◽

Soret Band ◽

Cell System ◽

Size Exclusion ◽

Heme Binding ◽

Systematic Analysis ◽

Molar Ratios ◽

Recombinant Production ◽

Wide Range ◽

Exclusion Chromatography

Plasma hemopexin (HPX) is the key antioxidant protein of the endogenous clearance pathway that limits the deleterious effects of heme released from hemoglobin and myoglobin (the term “heme” is used in this article to denote both the ferrous and ferric forms). During intra-vascular hemolysis, heme partitioning to protein and lipid increases as the plasma concentration of HPX declines. Therefore, the development of HPX as a replacement therapy during high heme stress could be a relevant intervention for hemolytic disorders. A logical approach to enhance HPX yield involves recombinant production strategies from human cell lines. The present study focuses on a biophysical assessment of heme binding to recombinant human HPX (rhHPX) produced in the Expi293FTM (HEK293) cell system. In this report, we examine rhHPX in comparison with plasma HPX using a systematic analysis of protein structural and functional characteristics related to heme binding. Analysis of rhHPX by UV/Vis absorption spectroscopy, circular dichroism (CD), size-exclusion chromatography (SEC)-HPLC, and catalase-like activity demonstrated a similarity to HPX fractionated from plasma. In particular, the titration of HPX apo-protein(s) with heme was performed for the first time using a wide range of heme concentrations to model HPX–heme interactions to approximate physiological conditions (from extremely low to more than two-fold heme molar excess over the protein). The CD titration data showed an induced bisignate CD Soret band pattern typical for plasma and rhHPX versions at low heme-to-protein molar ratios and demonstrated that further titration is dependent on the amount of protein-bound heme to the extent that the arising opposite CD couplet results in a complete inversion of the observed CD pattern. The data generated in this study suggest more than one binding site in both plasma and rhHPX. Furthermore, our study provides a useful analytical platform for the detailed characterization of HPX–heme interactions and potentially novel HPX fusion constructs.

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Ionophore-sensitive spectral shift of carotenoid induced by ferricyanide in chromatophores from Rhodopseudomonas sphaeroides

Plant and Cell Physiology ◽

10.1093/oxfordjournals.pcp.a076023 ◽

1980 ◽

Keyword(s):

Spectral Shift ◽

Rhodopseudomonas Sphaeroides

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Carboxyhemoglobin determination by second-derivative spectroscopy.

Clinical Chemistry ◽

10.1093/clinchem/31.2.279 ◽

1985 ◽

Vol 31 (2) ◽

pp. 279-281 ◽

Cited By ~ 17

Author(s):

J Parks ◽

H G Worth

Keyword(s):

Spectrum Analysis ◽

Spectral Shift ◽

Zero Order ◽

Reduced Form ◽

Second Derivative ◽

Derivative Spectrum ◽

Derivative Spectroscopy ◽

Set Up ◽

Second Derivative Spectroscopy

Abstract In this procedure hemoglobin is converted to its reduced form and the magnitude of the zero-order spectral shift of the reduced hemoglobin peak at 430 nm to the carboxyhemoglobin peak at 418 nm is determined by second-derivative spectrum analysis. The method is simple, straightforward to set up, and rapid. A result may be obtained within 15 min of receiving the sample. It is sufficiently sensitive to differentiate carboxyhemoglobin concentration in the blood of smokers and nonsmokers.

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