scholarly journals Fluorometry of natural latex from Maclura pomifera

2019 ◽  
Vol 2 (1) ◽  
Keyword(s):  
Uv Light ◽  
Fluorescence Emission ◽  
Fluorescence Excitation Spectrum ◽  
Computer Assisted ◽  
Fluorescence Emission Spectrum ◽  
Small Tree ◽  
Strong Fluorescence ◽  
Fluorescence Excitation ◽  
Maclura Pomifera ◽  
Bright Green

Maclura pomifera is a small tree that produces rot-resistant wood and a strange fruit called an Osage orange which is bright green. The fruits contain a high content of latex with strong fluorescence in UV light, similar in color to the green-yellow fluorescence of uranyl glass. Measurements were made using a computer-assisted microscope with grating mono chromators in both excitation and emission pathways. A photomultiplier was calibrated using a tungsten illuminator, then a mercury illuminator was used to measure the fluorescence emission spectrum: the peak was at 530 nm (green-yellow). A xenon illuminator was used to measure the fluorescence excitation spectrum: the peak was at 380 nm (UV).

scholarly journals Combining Hollow Core Photonic Crystal Fibers with Multimode, Solid Core Fiber Couplers through Arc Fusion Splicing for the Miniaturization of Nonlinear Spectroscopy Sensing Devices

Fibers ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 77 ◽  
Author(s):  
Hanna Stawska ◽  
Maciej Popenda ◽  
Elżbieta Bereś-Pawlik
Keyword(s):  
Photonic Bandgap ◽  
Average Power ◽  
Fluorescence Emission ◽  
Nonlinear Spectroscopy ◽  
Fluorescence Emission Spectrum ◽  
Solid Core ◽  
Hollow Core ◽  
Fluorescence Excitation ◽  
Photonic Bandgap Fiber ◽  
Sensing Applications

The presence of fiber optic devices, such as couplers or wavelength division multiplexers, based on hollow-core fibers (HCFs) is still rather uncommon, while such devices can be imagined to greatly increase the potential of HCFs for different applications, such as sensing, nonlinear optics, etc. In this paper, we present a combination of a standard, multimode fiber (MMF) optic coupler with a hollow core photonic bandgap fiber through arc fusion splicing and its application for the purpose of multiphoton spectroscopy. The presented splicing method is of high affordability due to the low cost of arc fusion splicers, and the measured splicing loss (SL) of the HCF-MMF splice is as low as (0.32 ± 0.1) dB, while the splice itself is durable enough to withstand a bending radius (rbend) of 1.8 cm. This resulted in a hybrid between the hollow core photonic bandgap fiber (HCPBF) and MMF coupler, delivering 20 mW of average power and 250-fs short laser pulses to the sample, which was good enough to test the proposed sensor setup in a simple, proof-of-concept multiphoton fluorescence excitation-detection experiment, allowing the successful measurement of the fluorescence emission spectrum of 10−5 M fluorescein solution. In our opinion, the presented results indicate the possibility of creating multi-purpose HCF setups, which would excel in various types of sensing applications.

Fluorescence of farnesene oxidation products in extracts and intact fruits as related to the development of superficial scald during storage of ‘Antonovka’ apples

1994 ◽  
Vol 102 ◽  
pp. 443-446
Author(s):  
M. N. Merzlyak ◽  
O. B. Chivkunova ◽  
S. I. Pogosyan ◽  
L. I. Kuznetsova ◽  
N. P. Ponomareva ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Fluorescence Emission ◽  
Fluorescence Analysis ◽  
Fluorescence Excitation Spectrum ◽  
Unsaturated Hydrocarbon ◽  
Oxidation Products ◽  
Fluorescence Excitation ◽  
Superficial Scald ◽  
Sensitive Tool ◽  
Apple Fruits

SynopsisThe oxidation products of unsaturated hydrocarbon α-farnesene that accumulate in cuticular lipids of stored apple fruits and are involved in the development of superficial scald showed UV fluorescence. The fluorescence emission band was localised at about 330 nm; the fluorescence excitation spectrum resembles the absorption spectrum of the products, but was more resolved. The corresponding fluorescence was recorded from the surfaces of intact apple fruits. It appears that the fluorescence analysis of farnesene oxidation products is a useful, specific, and sensitive tool to follow their concentrations both in extracts and intact fruits.

scholarly journals Gallic Acid-Containing Gelatin-Based Nonwoven Mat with Synergistic Photodegradation and Photoindication Function for Reducing Nicotine

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4245
Author(s):  
Meng-Yi Bai ◽  
Ting-Teng Wang
Keyword(s):  
Emission Spectrum ◽  
Gallic Acid ◽  
Cigarette Smoke ◽  
High Performance ◽  
Uv Light ◽  
Liquid Paraffin ◽  
Fluorescence Emission ◽  
Tween 80 ◽  
Fluorescence Emission Spectrum ◽  
Natural Polymer

Cigarette smoking is a popular habit that has negative health consequences for populations. In this study, we developed a gallic acid-containing, gelatin-based nonwoven mat with photodegradation and photoindication functions. This could react with sidestream cigarette smoke and simultaneously inhibit the activity of the microbe growth in the air. The results of a fluorescence emission spectrum evidenced this photoindication function. Neither the nicotine nor gallic acid showed a redshift emission spectrum. However, the emission spectrum of the nonwoven mat exhibited the redshift and increased in intensity after absorbing the sidestream cigarette smoke. In this spectral evidence, the natural polymer played a key role in the photoindication function’s display because it could dissolve the nicotine of the sidestream cigarette smoke and cause it to react with the gelatin structure. The high performance liquid chromatography–mass spectroscopy results indicated that the gallic acid and ultraviolet (UV) light enhanced the absorption of nicotine and nicotine-like derivatives, which were dissolved by the Tween 80 of nonwoven mat. The liquid paraffin and Tween 80 could oxidize, dehydrogenate, and demethylate the nicotine that was absorbed by the gelatin nonwoven mat. In conclusion, the nonwoven mat developed in this study provided the functions to filter the nicotine of sidestream smoke and activate the photoindication property by absorbing 365-nm UV light.

scholarly journals Intra-domain communication between the N-terminal and DNA-binding domains of the androgen receptor: modulation of androgen response element DNA binding

2005 ◽  
Vol 34 (3) ◽  
pp. 603-615 ◽  
Author(s):  
Jacqueline Brodie ◽  
Iain J McEwan
Keyword(s):  
Androgen Receptor ◽  
Dna Binding ◽  
Fluorescence Emission ◽  
Progesterone Receptors ◽  
Fluorescence Emission Spectrum ◽  
Response Element ◽  
Amino Terminal ◽  
Binding Domains ◽  
Receptor Modulation

The androgen receptor (AR) is a ligand-activated transcription factor that recognises and binds to specific DNA response elements upon activation by the steroids testosterone or dihydrotestosterone. In vitro, two types of response element have been characterised - non-selective elements that bind the androgen, glucocorticoid and progesterone receptors, and androgen receptor-selective sequences. In the present study, the allosteric effects of DNA binding on the receptor amino-terminal domain (NTD) were studied. Binding to both types of DNA response element resulted in changes in the intrinsic fluorescence emission spectrum for four tryptophan residues within the AR-NTD and resulted in a more protease-resistant conformation. In binding experiments, it was observed that the presence of the AR-NTD reduced the affinity of receptor polypeptides for binding to both selective and non-selective DNA elements derived from the probasin, PEM and prostatin C3 genes respectively, without significantly altering the protein–base pair contacts. Taken together, these results highlight the role of intra-domain communications between the AR-NTD and the DNA binding domain in receptor structure and function.

Two-Photon Fluorescence Excitation Spectrum of 1,6-Methano-[10]annulene

2000 ◽  
Vol 104 (28) ◽  
pp. 6566-6572 ◽  
Author(s):  
Lorenzo Catani ◽  
Cristina Gellini ◽  
Laura Moroni ◽  
Pier Remigio Salvi
Keyword(s):  
Excitation Spectrum ◽  
Fluorescence Excitation Spectrum ◽  
Fluorescence Excitation ◽  
Two Photon ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence

Synthesis, Photochromism and Optical Recording Properties of a Diarylethene Materials Bearing an Isoxazole Unit

2012 ◽  
Vol 583 ◽  
pp. 125-129 ◽  
Author(s):  
Xiao Ting Li ◽  
Hui Li ◽  
Gang Liu
Keyword(s):  
Thermal Stability ◽  
Uv Light ◽  
Amorphous Film ◽  
Optical Storage ◽  
Optical Recording ◽  
Strong Fluorescence ◽  
Good Thermal Stability ◽  
Closed Ring ◽  
Open Ring ◽  
Hexane Solution

A new unsymmetrical photochromic diarylethene, 1-(3,5-dimethyl-4-isoxazolyl)-2-[2-methyl-5-(4-formylphenyl)-3- thienyl]perfluorocyclopentene(1a) were synthesized, and its properties, such as photochromism and fluorescence properties, were investigated in detail. The results showed that this compound had good thermal stability and exhibited reversible photochromism, changing from colorless to darkred after irradiation with UV light both in solution and in PMMA amorphous film, the maxima absorption of its closed-ring isomer 1b are 529 nm and 541 nm respectively. The open-ring isomer of the diarylethene 1a exhibited relatively strong fluorescence at 492 nm in hexane solution (2 × 10-5 mol/L) when excited at 418 nm. The fluorescence intensity decreased along with the photochromism upon irradiation with 297 nm light. This new photochromic system also exhibited remarkable optical storage character.

Physiological Significance of Overproduced Carotenoids in Transformants of the Cyanobacterium Synechococcus PCC7942

1999 ◽  
Vol 54 (3-4) ◽  
pp. 191-198
Author(s):  
Navassard V. Karapetyan ◽  
Ute Windhövel ◽  
Alfred R. Holzwarth ◽  
Peter Böger
Keyword(s):  
Protein Complexes ◽  
Photosynthetic Apparatus ◽  
Fluorescence Emission ◽  
Fluorescence Induction ◽  
Carotenoid Content ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Whole Cells ◽  
Fluorescence Excitation Spectra ◽  
Synechococcus Pcc7942

Abstract The functional location of carotenoids in the photosynthetic apparatus of -crtB and -pys transformants of the cyanobacterium Synechococcus PCC7942 was studied and compared with a control strain -pFP 1-3. These transformants overproduce carotenoids due to the insertion of an additional foreign phytoene synthase gene. A higher carotenoid content was found for -crtB and -pys transformants both in whole cells and isolated membranes; the -crtB transformant was also enriched with chlorophyll. 77-K fluorescence emission and excitation spectra of the phycobilin-free membranes were examined for a possible location of overproduced carotenoids in pigment-protein complexes in situ. A similar ratio of the amplitudes of fluorescence bands at 716 and 695 nm emitted by photosystems I and II, found for the three strains, indicates that the stoichiometry between photosystems of the transformants was not changed. Overproduced carotenoids are not located in the core antenna of photosys­ tem I, since 77-K fluorescence excitation spectra for photosystem I of isolated membranes from the studied strains do not differ in the region of carotenoid absorption. When illuminated with light of the same intensity but different quality, absorbed preferentially by either carotenoids, chlorophylls or phycobilins, respectively, oxygen evolution was found always higher in the transformants -crtB and -pys than in -pFP 1-3 control cells. Identical kinetics of fluorescence induction of all strains under carotenoid excitation did not reveal a higher activity of photosystem II in cells enriched with carotenoids. It is suggested that overproduced carotenoids of the transformants are not involved in photosynthetic light-harvesting; rather they may serve to protect the cells and its membranes against photodestruction.

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