Unusual temperature-sensitive excimer fluorescence from discrete π–π dimer stacking of anthracene in a crystal

2019 ◽  
Vol 21 (27) ◽  
pp. 14511-14515 ◽  
Author(s):  
Yue Shen ◽  
Haichao Liu ◽  
Jungang Cao ◽  
Shitong Zhang ◽  
Weijun Li ◽  
...  
Keyword(s):  
Blue Shift ◽  
Temperature Sensitive ◽  
Excimer Fluorescence ◽  
Increasing Temperature

An unusual blue shift in excimer fluorescence with increasing temperature was observed from a crystal with a discrete π–π anthracene dimer.

scholarly journals Dynamics and Protein–Solvent Interactions of Hemoglobin in T and R Quaternary Conformation

2002 ◽  
Vol 16 (3-4) ◽  
pp. 227-233 ◽  
Author(s):  
Chiara Caronna ◽  
Antonio Cupane
Keyword(s):  
Quaternary Structure ◽  
Dynamic Properties ◽  
Low Frequency ◽  
Helical Structure ◽  
Blue Shift ◽  
Peak Frequency ◽  
The Other ◽  
Solvent Interactions ◽  
Reported Data ◽  
Increasing Temperature

In this work we report the thermal behaviour of the amide I′ band of carbonmonoxy and deoxy hemoglobin in 65% v/v glycerolD8/D2O solutions and in the temperature interval 10–295 K. Following recent suggestions in the literature, we analyze the amide I′ band in terms of two components, one at about 1630 cm−1and the other at about 1650 cm−1, that are assigned to solvent‒exposed and buried α‒helical regions, respectively.For deoxy hemoglobin (in T quaternary structure) both components are narrower with respect to carbonmonoxy hemoglobin (in R quaternary structure), while the peak frequency blue shift observed, upon increasing temperature, for the component at about 1630 cm−1is smaller. The reported data provide evidence of the dependence of hemoglobin dynamic properties upon the protein quaternary structure and suggest a more compact α‒helical structure of hemoglobin in T conformation, with reduced population of low‒frequency modes involving the solvent and protein.

Thermal sensitivity of isolated vagal pulmonary sensory neurons: role of transient receptor potential vanilloid receptors

2006 ◽  
Vol 291 (3) ◽  
pp. R541-R550 ◽  
Author(s):  
Dan Ni ◽  
Qihai Gu ◽  
Hong-Zhen Hu ◽  
Na Gao ◽  
Michael X. Zhu ◽  
...  
Keyword(s):  
Sensory Neurons ◽  
Transient Receptor Potential ◽  
Thermal Sensitivity ◽  
Receptor Potential ◽  
Ruthenium Red ◽  
Transient Receptor Potential Vanilloid ◽  
Temperature Sensitive ◽  
Inward Current ◽  
Transient Receptor ◽  
Increasing Temperature

A recent study has demonstrated that increasing the intrathoracic temperature from 36°C to 41°C induced a distinct stimulatory and sensitizing effect on vagal pulmonary C-fiber afferents in anesthetized rats ( J Physiol 565: 295–308, 2005). We postulated that these responses are mediated through a direct activation of the temperature-sensitive transient receptor potential vanilloid (TRPV) receptors by hyperthermia. To test this hypothesis, we studied the effect of increasing temperature on pulmonary sensory neurons that were isolated from adult rat nodose/jugular ganglion and identified by retrograde labeling, using the whole cell perforated patch-clamping technique. Our results showed that increasing temperature from 23°C (or 35°C) to 41°C in a ramp pattern evoked an inward current, which began to emerge after exceeding a threshold of ∼34.4°C and then increased sharply in amplitude as the temperature was further increased, reaching a peak current of 173 ± 27 pA ( n = 75) at 41°C. The temperature coefficient, Q10, was 29.5 ± 6.4 over the range of 35–41°C. The peak inward current was only partially blocked by pretreatment with capsazepine (Δ I = 48.1 ± 4.7%, n = 11) or AMG 9810 (Δ I = 59.2 ± 7.8%, n = 8), selective antagonists of the TRPV1 channel, but almost completely abolished (Δ I = 96.3 ± 2.3%) by ruthenium red, an effective blocker of TRPV1–4 channels. Furthermore, positive expressions of TRPV1–4 transcripts and proteins in these neurons were demonstrated by RT-PCR and immunohistochemistry experiments, respectively. On the basis of these results, we conclude that increasing temperature within the normal physiological range can exert a direct stimulatory effect on pulmonary sensory neurons, and this effect is mediated through the activation of TRPV1, as well as other subtypes of TRPV channels.

scholarly journals Temperature / pressure-dependent luminescence spectra of square-planar complexes

2014 ◽  
Vol 70 (a1) ◽  
pp. C1714-C1714
Author(s):  
Stéphanie Poirier ◽  
Christian Reber ◽  
Pierre Libioulle
Keyword(s):  
Structural Changes ◽  
Theoretical Calculations ◽  
Blue Shift ◽  
Red Shift ◽  
Crystalline Lattice ◽  
Luminescence Spectra ◽  
Electron Configuration ◽  
Square Planar ◽  
Square Planar Complexes ◽  
Increasing Temperature

Luminescence properties of square-planar complexes of platinum(II) and palladium(II) with a d8 electron configuration were investigated. Blue shift of the maxima of the luminescence spectra occur for pressure-dependent spectra of several complexes of both metals. This is due to a structural compression of the crystalline lattice, which causes a destabilization of the LUMO orbital for theses complexes. Other structural changes can also occur, providing a more important slope of the blue shift. Also, intermolecular interactions cause a red shift in pressure-dependent spectra. In temperature-dependent spectra, opposite trends occur for several analog complexes. Palladium(II) complexes show a red shift of luminescence maxima with increasing temperature. Platinum(II) compounds exhibit a blue shift. This difference is explained with theoretical calculations of luminescence spectra. In these trends, the dominant effect is due to an increase of vibronic contributions with temperature. We also present a complex of platinum(II) in which the structural effect is dominant in the spectra with increasing temperature, leading to a red shift. This rare effect allows the study of structural changes with temperature for square-planar platinum(II) complex.

scholarly journals Structure–Function Correlations in Sputter Deposited Gold/Fluorocarbon Multilayers for Tuning Optical Response

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1249 ◽  
Author(s):  
Pallavi Pandit ◽  
Matthias Schwartzkopf ◽  
André Rothkirch ◽  
Stephan V. Roth ◽  
Sigrid Bernstorff ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Morphological Changes ◽  
Volume Ratio ◽  
Blue Shift ◽  
Grazing Incidence ◽  
Optical Response ◽  
Collective Effects ◽  
Local Surface Plasmon Resonance ◽  
Sputter Deposited ◽  
Increasing Temperature

A new strategy to nanoengineer gold/fluorocarbon multilayer (ML) nanostructures is reported. We have investigated the morphological changes occurring at the metal–polymer interface in ML structures with varying volume fraction of gold (Au) and the kinetic growth aspect of the microscale properties of nano-sized Au in plasma polymer fluorocarbon (PPFC). Investigations were carried out at various temperatures and annealing times by means of grazing incidence small-angle and wide-angle X-ray scattering (GISAXS and GIWAXS). We have fabricated a series of MLs with varying volume fraction (0.12, 0.27, 0.38) of Au and bilayer periodicity in ML structure. They show an interesting granular structure consisting of nearly spherical nanoparticles within the polymer layer. The nanoparticle (NP) morphology changes due to the collective effects of NPs diffusion within ensembles in the in-plane vicinity and interlayer with increasing temperature. The in-plane NPs size distinctly increases with increasing temperature. The NPs become more spherical, thus reducing the surface energy. Linear growth of NPs with temperature and time shows diffusion-controlled growth of NPs in the ML structure. The structural stability of the multilayer is controlled by the volume ratio of the metal in polymer. At room temperature, UV-Vis shows a blue shift of the plasmon peak from 560 nm in ML Au/PTFE_1 to 437 nm in Au/PTFE_3. We have identified the fabrication and postdeposition annealing conditions to limit the local surface plasmon resonance (LSPR) shift from Δ λ L S P R = 180 nm (Au/PTFE_1) to Δ λ L S P R = 67 nm (Au/PTFE_3 ML)) and their optical response over a wide visible wavelength range. A variation in the dielectric constant of the polymer in presence of varying Au inclusion is found to be a possible factor affecting the LSPR frequency. Our findings may provide insights in nanoengineering of ML structure that can be useful to systematically control the growth of NPs in polymer matrix.

Preparation and Drug Release Behavior from a Temperature-Sensitive Poly(aspartic Acid) Derivatives Hydrogel

2013 ◽  
Vol 711 ◽  
pp. 18-21
Author(s):  
Kui Lin Deng ◽  
Chun Xiu Li ◽  
Ting Gao ◽  
Xiao Dan Fu ◽  
Wen Hui Jin ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Aspartic Acid ◽  
Ph Value ◽  
Phosphate Buffer Solution ◽  
Temperature Sensitive ◽  
Release Behavior ◽  
Buffer Solution ◽  
Drug Release Behavior ◽  
Drug Delivery Carrier ◽  
Increasing Temperature

In this paper, a new pH/temperature-sensitive beads with semi-interpenetrating polymeric network based on sodium alginate(SA) and poly(aspartic acid) derivatives(M-E-PSI) were prepared using as drug delivery carrier. With indomethacin as a drug model，we investigated the release behaviors of indomethacin in different pH value, temperature and ratio of SA/ M-E-PSI. It turned out that the release amount of indomethacin in pH=2.1 phosphate buffer solution(PBS) was evidently higher than that in pH=7.4 PBS. And also, the release amount of indomethacin was also increased with increasing temperature and poly(aspartic acid) derivatives content in the beads.

Synthesis and Optical Properties of Li3Ba2La3(MoO4)8:Sm3+ Powders for pcLEDs

2014 ◽  
Vol 69 (2) ◽  
pp. 183-192 ◽  
Author(s):  
Florian Baur ◽  
Arturas Katelnikovas ◽  
Simas Sakirzanovas ◽  
Ralf Petry ◽  
Thomas Jüstel
Keyword(s):  
Optical Properties ◽  
Energy Levels ◽  
Synthesis Method ◽  
Thermal Quenching ◽  
Emission Spectra ◽  
Blue Shift ◽  
Gaussian Peak ◽  
Peak Fitting ◽  
Subsequent Decrease ◽  
Increasing Temperature

A series of Sm3+-activated molybdates Li3Ba2(La1−xSmx)3(MoO4)8 with 0<̲x<̲1 (0% to 100% Sm3+) have been prepared by the conventional solid-state synthesis method, and their optical properties were investigated. Reflection, excitation and emission spectra were recorded and put in relation to the various [Xe]4 f 5 → [Xe]4 f 5 transitions of Sm3+. The positions of the charge transfer bands of Sm3+ and Mo6+ were resolved by Gaussian peak fitting. Emission spectra recorded at 100 K revealed the Stark sublevels of the Sm3+ energy levels. Time-dependent emission measurements of the 4G5/2 →6H9/2 transition were performed to disentangle the influence of temperature and activator concentration on the decay constants. The results are discussed in the context of the structure of the host material. Sm3+ occupies two different crystallographic sites at higher activator concentrations, which results in a bi-exponential decay curve. Temperature-dependent emission spectra were recorded to determine the thermal quenching behavior of the material. Internal and external quantum efficiencies (IQE and EQE) have been calculated. The IQE is independent of temperature, while the emission intensity strongly decreases at temperatures higher than 400 K. It is concluded that the photon escape efficiency in Li3Ba2La3(MoO4)8 correlates with temperature. An EQE of 44% was achieved for the 2% Sm3+ sample, which is comparatively high for Sm3+. Color points and luminous efficacies were calculated. The color point is independent of the Sm3+ concentration, but a blue-shift was observed with increasing temperature. This shift may be caused by lattice expansion and a subsequent decrease of spin-orbit coupling.

Thermal Shift and Broadening of Spectral Lines in Neodymium Doped Garnets

1999 ◽  
Vol 560 ◽  
Author(s):  
Xuesheng Chen ◽  
Baldassare Di Bartolo
Keyword(s):  
Line Width ◽  
Blue Shift ◽  
Red Shift ◽  
Spectral Lines ◽  
Temperature Range ◽  
Different Temperatures ◽  
Line Widths ◽  
Increasing Temperature ◽  
Thermal Shift

ABSTRACTThermal shift and broadening of sharp luminescence lines in three Nd-doped laser garnet crystals, GGG, GSGG, and CYMGG, are investigated in a temperature range of 78 to 600K. These lines are due to the 4F3/2 → 4I9/2 (∼0.94μ) and 4F3/2 → 4I11/2 (∼lμ) transitions. Line widths and positions at different temperatures are reported for the lines of RI→Yl, RI→Y2, R2→Y3, RI→Z5 in GGG:Nd, RI→Y1, RI→Y2, R2→Y1, R2→Y3, RI→Y6, R2→Y6, RI→Z5 in GSGG:Nd,Cr, and R2→Y1, RI→Z5 in CYMGG:Nd,Cr. We observed that all the lines shift to longer wavelengths (red shift) with increasing temperature except for the R1,2 →Z5 lines that shift to shorter wavelength (blue shift) in all the three garnet crystals. For the widths, all the lines become broader with increasing temperature. It was also observed that the line width in the germanium garnet CYMGG is much broader than in GGG and GSGG.

scholarly journals enhancer of seizure: A New Genetic Locus in Drosophila melanogaster Defined by Interactions With Temperature-Sensitive Paralytic Mutations

Genetics ◽  
1987 ◽  
Vol 116 (3) ◽  
pp. 423-431
Author(s):  
Durgadas P Kasbekar ◽  
James C Nelson ◽  
Linda M Hall
Keyword(s):  
Genetic Locus ◽  
P Element ◽  
Recessive Mutation ◽  
Temperature Sensitive ◽  
Giant Fiber ◽  
Membrane Excitability ◽  
Muscle System ◽  
Salivary Gland Polytene Chromosome ◽  
Electrophysiological Studies ◽  
Increasing Temperature

ABSTRACT Mutations in the enhancer of seizure (e(sei)) locus have been isolated on the basis of their ability to cause temperature-induced paralysis of alleles at the seizure (sei) locus at temperatures at which these mutations ordinarily do not paralyze. This enhancer is specific to the seizure locus and is without effect on other temperature-sensitive paralytic mutants including para, nap, tip-E and shi. This suggests that the enhancer responds specifically to the mechanism of paralysis mediated by the seizure mutations. The e(sei) is a recessive mutation which maps to 39.0 on the left arm of chromosome 3. Deficiency mapping has placed it at 69A4-B5 on the salivary gland polytene chromosome map. When a new enhancer allele was isolated following P-M hybrid dysgenesis, there was a concomitant P-element insertion at 69B. In the absence of seizure mutations, the enhancer mutation causes non-temperature dependent hyperactivity when agitated and interferes with the climbing response. Electrophysiological studies examined the effects of increasing temperature on electrical activity in the adult giant fiber/flight muscle system. Neuronal hyperactivity was seen in both e(sei) and sei single mutant homozygotes, but not in wild type. The hyperactivity was more severe in the sei;e(sei) double mutants. The correlation between the physiological effects and the mutant behavior suggests that both sei and e(sei) cause membrane excitability defects. Since previous work has shown that seizure mutants affect [3H]saxitoxin binding to the voltage-sensitive sodium channel, e(sei) may code for a gene product which interacts with this channel.

scholarly journals Coupling between fast and slow oscillator circuits in Cancer borealis is temperature-compensated

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Daniel Powell ◽  
Sara A Haddad ◽  
Srinivas Gorur-Shandilya ◽  
Eve Marder
Keyword(s):  
Integer Number ◽  
Temperature Sensitive ◽  
Gastric Mill ◽  
Temperature Dependent ◽  
Cancer Borealis ◽  
Cycle Frequency ◽  
Temperature Changes ◽  
Wide Range ◽  
Similar Temperature ◽  
Increasing Temperature

Coupled oscillatory circuits are ubiquitous in nervous systems. Given that most biological processes are temperature-sensitive, it is remarkable that the neuronal circuits of poikilothermic animals can maintain coupling across a wide range of temperatures. Within the stomatogastric ganglion (STG) of the crab, Cancer borealis, the fast pyloric rhythm (~1 Hz) and the slow gastric mill rhythm (~0.1 Hz) are precisely coordinated at ~11°C such that there is an integer number of pyloric cycles per gastric mill cycle (integer coupling). Upon increasing temperature from 7°C to 23°C, both oscillators showed similar temperature-dependent increases in cycle frequency, and integer coupling between the circuits was conserved. Thus, although both rhythms show temperature-dependent changes in rhythm frequency, the processes that couple these circuits maintain their coordination over a wide range of temperatures. Such robustness to temperature changes could be part of a toolbox of processes that enables neural circuits to maintain function despite global perturbations.

Temperature Dependence of the Sole Mn2+ Emissions in Manganese Doped ZnS:Mn Quantum Dots

2010 ◽  
Vol 159 ◽  
pp. 572-577
Author(s):  
Xiao Song Zhang ◽  
Gao Feng Zhang ◽  
Qing Song Huang ◽  
Feng Wei Wei ◽  
Yong Liang Zhou
Keyword(s):  
Quantum Dots ◽  
Temperature Dependence ◽  
Emission Intensity ◽  
Blue Shift ◽  
Average Diameter ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Broad Emission Band ◽  
Emission Energy ◽  
Increasing Temperature

ZnS:Mn Quantum dots (QDs) excess of [S2-] were synthesized by the wet chemical precipitation method with an average diameter of 3.9 nm. Temperature dependence photoluminescence measurements of ZnS:Mn QDs excited at 330nm only show a clear broad emission band with peak at ～595nm assigned to the 4T1→6A1 transition within the 3d5 configuration of Mn2+ in QDs. Through the temperature dependence of emission intensity, emission energy and full widths at half maximum (FWHM), the mechanisms are analyzed to explain the temperature behavior of Mn2+ emission observed here reasonably. The Mn2+ emission intensity decreases with increasing temperature. And the blue shift of the Mn2+ emission energy increase is also observed for increasing the temperature. Furthermore, the FWHM shows weak temperature dependence below 110 K and shows an increase with temperature increasing above 110 K. Consequently, the intrinsic mechanisms of temperature dependence photoluminescence are investigated.

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