Effects of Linolenic Acid on the Spectral Properties and Picosecond Fluorescence of Pea Chloroplasts

1981 ◽  
Vol 36 (11-12) ◽  
pp. 1021-1024 ◽  
Author(s):  
S. S. Brody ◽  
J. Barber ◽  
C. Tredwell ◽  
G. Beddard
Keyword(s):  
Absorption Spectrum ◽  
Linolenic Acid ◽  
Thylakoid Membrane ◽  
Spectral Properties ◽  
Room Temperature ◽  
Life Time ◽  
Synergistic Action ◽  
Fast Component ◽  
Spectral Changes

Abstract Linolenic acid induces changes in the absorption spectrum and in the picosecond fluorescence of pea chloroplasts. The effects of linolenic acid are dependent on concentration and time. Linolenic acid increases the fluorescence life time of chloroplasts at room temperature. The contribution of the slow fluorescence component relative to the fast component is increased almost 10 fold in the presence of 0.5 mᴍ linolenic acid. The synergistic action of digitonin and linolenic acid increases the ratio of “closed” to “open” traps in the photosynthetic units. Upon addition of 0.5 mᴍ linolenic acid there are increases in absorbance at 676 and 436 nm, and decreases in absorbance at 705 and 496 nm. Some of the spectral changes have a biphasic character, they reach a maxi um um after about 30 min then start to reverse. Based on the spectral changes at 496 and 705 nm it appears that linolenic acid has at least two effects, i.e. it modifies the thylakoid membrane and secondarily decreases the concentration of P700, respectively.

Effects of Linolenic Acid on System II and System I-Associated Light Induced Changes in Absorption of Chloroplasts

1970 ◽  
Vol 25 (4) ◽  
pp. 367-372 ◽  
Author(s):  
S. S. Brody ◽  
M. Brody ◽  
G. Döring
Keyword(s):  
Linolenic Acid ◽  
Thylakoid Membrane ◽  
Pronounced Effect ◽  
Spectral Change ◽  
Induced Absorption ◽  
Spectral Changes ◽  
No Inhibition ◽  
Induced Changes

The addition of linolenic acid to chloroplasts and sub-chloroplast particles has pronounced effect on light induced absorption changes. At a concentration of 10-4 M linolenic acid or [LINO] /[CHL] ≈ 2 (on a mole to mole basis) spectral changes associated with System II are diminished to 50 percent. In this same range there is also a small increase in the spectral change ascribed to System I; this increase may reflect the action of linolenic acid in uncoupling phosphorylation. While at [LINO] / [CHL] ≈ 4, light induced absorption changes of System II are completely blocked, there seems to be no inhibition of System I. The effects of linolenic acid on the 515 nm spectral change are interpreted as an increase in the permeability of the thylakoid membrane.

scholarly journals Multicolour single molecule emission and excitation spectroscopy reveals extensive spectral shifts

2015 ◽  
Vol 184 ◽  
pp. 207-220 ◽  
Author(s):  
Lukasz Piatkowski ◽  
Esther Gellings ◽  
Niek F. van Hulst
Keyword(s):  
Single Molecule ◽  
Emission Spectroscopy ◽  
Spectral Properties ◽  
Absorption Maximum ◽  
Room Temperature ◽  
Emission Spectra ◽  
Excitation Wavelength ◽  
Ambient Conditions ◽  
Spectral Changes ◽  
Spectral Shifts

We explore the distribution and shape of single molecule spectra at room temperature, when embedded in a polymer host. Multicolour excitation and emission spectroscopy is implemented to capture the full inhomogeneous distribution. We observe dramatic spectral changes in a distribution of single quaterrylene diimide (QDI) molecules isolated in a PMMA matrix. The molecules are strongly blue shifted with respect to the ensemble absorption maximum and spread over a staggering 200 nm range. Despite these strong shifts, the shape of the emission spectra does not differ much between individual molecules. We demonstrate that a considerable number of molecules may be invisible in single molecule experiments, as they typically rely on only a single excitation wavelength, which predetermines which subensemble is probed in the experiment. Lastly, we make a first step towards single molecule excitation spectroscopy under ambient conditions, which allows us to determine the spectral range at which individual molecules absorb light most efficiently. We show how single molecule emission and excitation spectroscopies can complement each other and a combination of both techniques can help in understanding the origin of underlaying spectral properties of individual molecules.

scholarly journals Absorption and Emission Spectra for C60 Anions

1994 ◽  
Vol 14 (1-3) ◽  
pp. 155-160 ◽  
Author(s):  
Tatsuhisa Kato
Keyword(s):  
Absorption Spectrum ◽  
Absorption Band ◽  
Theoretical Analysis ◽  
Room Temperature ◽  
Emission Spectra ◽  
Mirror Image ◽  
Ir Absorption ◽  
Near Ir ◽  
Laser Experiments ◽  
Ir Bands

Absorption spectra are detected for C60− and C602− produced electrolytically in solution at room temperature. Theoretical analysis of the spectrum of C60− by CNDO/S calculations gives an interpretation of the characteristic near-IR bands, the weak visible bands, and the strong bands in the UV region. The emission spectrum of C60− is a mirror image of the near-IR absorption band, and the detection of the emission reconfirms our original assignment of the absorption spectrum. The nature of the spectrum of C602− is characterized by a similar orbital picture to that of C60−. Further laser experiments of significance are proposed.

scholarly journals Temperature Dependence of Hall Mobility AndCarrier Concentration of pb0.55S0.45 Films

2009 ◽  
Vol 6 (1) ◽  
pp. 129-134
Author(s):  
Baghdad Science Journal
Keyword(s):  
Hall Mobility ◽  
Room Temperature ◽  
Annealing Temperature ◽  
High Vacuum ◽  
Life Time ◽  
Mean Free Path ◽  
Charge Carriers ◽  
Evaporation Technique ◽  
Carrier Life Time ◽  
Type Conduction

Measurements of Hall effect properties at different of annealing temperature have been made on polycrystalline Pb0.55S0.45 films were prepared at room temperature by thermal evaporation technique under high vacuum 4*10-5 torr . The thickness of the film was 2?m .The carrier concentration (n) was observed to decrease with increasing the annealing temperature. The Hall measurements showed that the charge carriers are electrons (i.e n-type conduction). From the observed dependence on the temperature, it is found that the Hall mobility (µH), drift velocity ( d) carrier life time ( ), mean free path (?) were increased with increasing annealing temperature

Inter-Pulse Spectroscopy Based on Room-Temperature Pulsed Quantum-Cascade Laser for N2O Detection

2011 ◽  
Vol 128-129 ◽  
pp. 607-610
Author(s):  
Min Wang ◽  
Jie Chen ◽  
Niu Liu ◽  
Ya Wang
Keyword(s):  
Absorption Spectrum ◽  
Room Temperature ◽  
Single Point ◽  
High Sensitivity ◽  
Fast Response ◽  
Trace Gas ◽  
High Resolution Spectrum ◽  
Light Sources ◽  
Quantum Cascade ◽  
Pulse Spectroscopy

Mid-infrared lasers are very suitable for high-sensitive trace-gases detection for their wavelengths cover the fundamental absorption lines of most gases. Quantum-cascade (QC) lasers have been demonstrated to be ideal light sources with its special power, tuning and capability of operating in room-temperature. All these merits make it appropriate for the high resolution spectrum analysis. The absorption spectrum monitoring technology based on the QC laser pulsed operating in the room temperature, combining with the strong absorption of the gas molecule in the basic frequency, has become an effective way to monitor the trace gas with the characteristic of high sensitivity, good selectivity and fast response. In this paper, the inter-pulse spectroscopy based on a room-temperature distributed-feedback pulsed QC laser was introduced. Our approach to trace gas monitoring with QC lasers relies on short current pulses which are designed to produce even shorter light pulses. Each pulse corresponds to a single point in a spectrum. The N2O absorption spectrum centered at 2178.2cm-1was also obtained.

New data for lansfordite

1982 ◽  
Vol 46 (341) ◽  
pp. 453-457 ◽  
Author(s):  
R. J. Hill ◽  
J. H. Canterford ◽  
F. J. Moyle
Keyword(s):  
Absorption Spectrum ◽  
Low Temperature ◽  
Diffraction Pattern ◽  
Powder Diffraction ◽  
Room Temperature ◽  
X Ray ◽  
Infra Red ◽  
Bicarbonate Solutions

AbstractEuhedral crystals of the low-temperature mineral lansfordite, MgCO3 · 5H2O, have been prepared from saturated magnesium bicarbonate solutions at temperatures below 10°C. The crystals are monoclinic P21/a with a = 12.4758(7), b = 7.6258(4), c = 7.3463(6)Å, β = 101.762(6)°, V = 684.24Å3, Dcalc. = 1.693 g cm−3, Dobs. = 1.70(1) g m−3. At room temperature, the crystals slowly effloresce to produce pseudomorphs of nesquehonite, MgCO3 · 3H2O. Dehydration is complete at 300°C, with decarbonation taking place in the interval to 560°C. A new X-ray powder diffraction pattern is presented, and details of the infra-red absorption spectrum are discussed.

The Near-ultraviolet Absorption Spectrum of Diimide in Liquid Ammonia and its Decomposition between −65 and −38 °C

1974 ◽  
Vol 52 (13) ◽  
pp. 2513-2515 ◽  
Author(s):  
R. A. Back ◽  
C. Willis
Keyword(s):  
Absorption Spectrum ◽  
Gas Phase ◽  
Room Temperature ◽  
Liquid Ammonia ◽  
Vibrational Structure ◽  
Ultraviolet Absorption ◽  
Ultraviolet Absorption Spectrum ◽  
First Order ◽  
Rapid Decomposition ◽  
Near Ultraviolet

The near-ultraviolet absorption spectrum of diimide in liquid ammonia at −50 °C is shifted about 500 Å to the red compared with the gas-phase spectrum, with λmax = 4000 Å. The spectrum is also broadened and the vibrational structure largely obscured. It is suggested that hydrogen bonding is responsible for these changes.Diimide is much more stable in liquid ammonia between −65 and −38 °C than in the gas phase at room temperature. A first-order decay is observed with Arrhenius parameters of A = 1.9 × 103 s−1 and E = 6.6 kcal/mol; this is always preceded by a more rapid, higher-order initial decay which may be related to the rapid decomposition observed during vaporization.

scholarly journals Effect of storage on the fatty acids of dried ryegrass

1967 ◽  
Vol 21 (3) ◽  
pp. 599-608 ◽  
Author(s):  
J. W. Czerkawski
Keyword(s):  
Fatty Acids ◽  
Linolenic Acid ◽  
Dry Matter ◽  
Room Temperature ◽  
The Other ◽  
Mould Growth ◽  
Total Fatty Acids ◽  
Higher Temperature ◽  
Types Of Change ◽  
Oleic And Linoleic Acids

1. The compositions of the fatty acids in ryegrass were determined in fresh samples, and in samples dried at room temperature for 26 h, at 50° and for 18 h or at 100° for 12 h. The drying of grass resulted in a small increase in palmitic acid and a decrease in linolenic acid in the total fatty acids.2. Samples of grass dried at 50° and 100° were stored at three relative humidities (rh < 3%, 47% and 80%) for 13 months.3. There were marked changes in the samples stored at 80% rh, with an onset of mould growth and a loss of dry matter. The samples stored at lower humidities had no mould.4. There were two types of change in the fatty acids during storage. The deterioration brought about and mould was accompanied by a decrease in the concentration of linolenic acid and an increase in the concentrations of oleic and linoleic acids. The other type of change observed at the lower humidities resulted in a decrease in the content of linolenic and an increase in the content of palmitic, and did not affect the amounts of oleic and linoleic cells.5. There was little difference between the changes that occurred in the composition of the total fatty acids of the grass dried at 50° and of that dried at 100°. The changes that were at all significant appeared to occur less rapidly, particularly in the early months of storage, in the grass dried at the higher temperature for the shorter time.

Identification Of The Procoagulant Species In Ellagic Acid Solutions

1981 ◽  
Author(s):  
Paul E Bock ◽  
Joseph D Shore
Keyword(s):  
New Species ◽  
Light Scattering ◽  
Blood Coagulation ◽  
Ellagic Acid ◽  
Spectral Properties ◽  
Metal Ion ◽  
Factor Xii ◽  
Acid Solutions ◽  
Absorbance Spectrum ◽  
Spectral Changes

The species of ellagic acid responsible for initiating intrinsic blood coagulation has been characterized. Ellagic acid is soluble ata level of 30 ± 10 μM in pH 7.4 Tris-saline buffer at 22°C. Dilution of soluble ellagic acid resulted in enhanced plasma procoagulant and kallikrein generating activity, and the appearance of a new absorbance spectrum. These effects were prevented by 1 mi4 EDTA, and the new species could be removed by centrifugation. Addition of stoichiometric Cu2+ to Millipore-filtered soluble ellagic acid generated an absorbance spectrum similar to that caused by dilution in the absence of EDTA, as well as procoagulant and kallikrein activities. Zn2+ and Co2+ caused similar spectral changes and prekail ikrein activation. Although no turbidity was visible and the spectral properties did not indicate extensive light scattering, centrifugation resulted in loss of the absorbance spectrum and activity. We conclude that the procoagulant activity of ellagic acid solutions can be ascribed to slowly settling insoluble aggregates of ellagic acid-metal ion complexes, which are formed with adventitious metal ions present in the diluting buffer. Formation of these aggregates could be prevented but not reversed by 1 mM EDTA. Although soluble ellagic acid may bind to Factor XII, it does not initiate blood coagulation or prekallikrein activation, since these activities were only associated with the insoluble species.

Sign in / Sign up

Export Citation Format

Share Document