Twist-Bend Nematic Phase: Role of Third-Order Legendre Polynomial Term in Chiral Interaction Potential

To take advantage of the singular properties of matter, as well as to characterize it, we need to interact with it. The role of optical spectroscopies is to enable us to demonstrate the existence of physical objects by observing their response to light excitation. The ability of spectroscopy to reveal the structure and properties of matter then relies on mathematical functions called optical (or dielectric) response functions. Technically, these are tensor Green’s functions, and not scalar functions. The complexity of this tensor formalism sometimes leads to confusion within some articles and books. Here, we do clarify this formalism by introducing the physical foundations of linear and non-linear spectroscopies as simple and rigorous as possible. We dwell on both the mathematical and experimental aspects, examining extinction, infrared, Raman and sum-frequency generation spectroscopies. In this review, we thus give a personal presentation with the aim of offering the reader a coherent vision of linear and non-linear optics, and to remove the ambiguities that we have encountered in reference books and articles.

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Nested Recharge Systems in Mountain Block Hydrology: High-Elevation Snowpack Generates Low-Elevation Overwinter Baseflow in a Rocky Mountain River

Water ◽

10.3390/w13162249 ◽

2021 ◽

Vol 13 (16) ◽

pp. 2249

Author(s):

Éowyn M. S. Campbell ◽

M. Cathryn Ryan

Keyword(s):

Rocky Mountain ◽

High Elevation ◽

Third Order ◽

Relative Temperature ◽

Local Flow ◽

Fracture Systems ◽

Lower Elevation ◽

Flow Systems ◽

Longitudinal Sampling

The majority of each year′s overwinter baseflow (i.e., winter streamflow) in a third-order eastern slopes tributary is generated from annual melting of high-elevation snowpack which is transmitted through carbonate and siliciclastic aquifers. The Little Elbow River and its tributaries drain a bedrock system formed by repeated thrust faults that express as the same siliciclastic and carbonate aquifers in repeating outcrops. Longitudinal sampling over an 18 km reach was conducted at the beginning of the overwinter baseflow season to assess streamflow provenance. Baseflow contributions from each of the two primary aquifer types were apportioned using sulfate, δ34SSO4, and silica concentrations, while δ18OH2O composition was used to evaluate relative temperature and/or elevation of the original precipitation. Baseflow in the upper reaches of the Little Elbow was generated from lower-elevation and/or warmer precipitation primarily stored in siliciclastic units. Counterintuitively, baseflow generated in the lower-elevation reaches originated from higher-elevation and/or colder precipitation stored in carbonate units. These findings illustrate the role of nested flow systems in mountain block recharge: higher-elevation snowmelt infiltrates through fracture systems in the cliff-forming—often higher-elevation—carbonates, moving to the lower-elevation valley through intermediate flow systems, while winter baseflow in local flow systems in the siliciclastic valleys reflects more influence from warmer precipitation. The relatively fast climatic warming of higher elevations may alter snowmelt timing, leaving winter water supply vulnerable to climatic change.

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Calculation of impact ionization coefficients with a third‐order Legendre polynomial expansion of the distribution function

Journal of Applied Physics ◽

10.1063/1.351188 ◽

1992 ◽

Vol 71 (4) ◽

pp. 1815-1822 ◽

Cited By ~ 11

Author(s):

Shiuh‐Luen Wang ◽

Neil Goldsman ◽

Kenneth Hennacy

Keyword(s):

Distribution Function ◽

Legendre Polynomial ◽

Impact Ionization ◽

Polynomial Expansion ◽

Third Order ◽

Ionization Coefficients

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Liquid crystal dimers and the twist-bend nematic phase: On the role of spacers and terminal alkyl chains

Journal of Molecular Liquids ◽

10.1016/j.molliq.2020.114391 ◽

2020 ◽

Vol 320 ◽

pp. 114391 ◽

Cited By ~ 1

Author(s):

Ewan Forsyth ◽

Daniel A. Paterson ◽

Ewan Cruickshank ◽

Grant J. Strachan ◽

Ewa Gorecka ◽

...

Keyword(s):

Liquid Crystal ◽

Nematic Phase ◽

Alkyl Chains

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Role of molecular bend angle and biaxiality in the stabilization of the twist-bend nematic phase

Soft Matter ◽

10.1039/d0sm00078g ◽

2020 ◽

Vol 16 (18) ◽

pp. 4350-4357 ◽

Cited By ~ 2

Author(s):

Wojciech Tomczyk ◽

Lech Longa

Keyword(s):

Field Theory ◽

Nematic Phase ◽

Mean Field Theory ◽

Mean Field ◽

Structural Features ◽

Bend Angle ◽

Nematic Phases

Within mean-field theory for V-shaped molecules, we have investigated how the alteration of a molecule's structural features influence the stabilization of modulated and non-modulated nematic phases.

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Functional heterogeneity of endothelial P2 purinoceptors in the cerebrovascular tree of the rat

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1999.277.3.h893 ◽

1999 ◽

Vol 277 (3) ◽

pp. H893-H900 ◽

Cited By ~ 28

Author(s):

Junping You ◽

T. David Johnson ◽

Sean P. Marrelli ◽

Robert M. Bryan

Keyword(s):

Cerebral Arteries ◽

No Synthase ◽

Third Order ◽

Selective Agonist ◽

Middle Cerebral Arteries ◽

Spontaneous Tone ◽

A Minor ◽

Calcium Activated Potassium Channel ◽

Dose Dependent

The effects of stimulating P2Y1 or P2Y2 purinoceptors on the endothelium of isolated middle cerebral arteries (MCAs), third-order branches of the MCA (bMCAs), and penetrating arterioles (PAs) of the rat were studied. After pressurization and development of spontaneous tone (25% contraction), resting diameters for MCAs, bMCAs, and PAs were 203 ± 5 ( n = 50), 99 ± 2 ( n = 42), and 87 ± 2 μm ( n = 53), respectively. Luminal application of the P2Y1-selective agonist 2-methylthioadenosine 5′-triphosphate elicited dose-dependent dilations (or loss of intrinsic tone) in MCAs but not in bMCAs or PAs. The dilation in MCAs was completely blocked by removal of the endothelium or by nitro-l-arginine methyl ester (10−5 M), an inhibitor of NO synthase. Luminal application of the P2Y2-selective agonist ATP elicited dilations in MCAs, bMCAs, and PAs. Removal of the endothelium abolished the dilations in all vessel groups. Dilations in MCAs have been shown to involve both NO and endothelium-derived hyperpolarizing factor (EDHF). The dilations in bMCAs and PAs had a minor NO component and prominent EDHF component; that is, 1) the dilations to ATP were not diminished by the combined inhibition of NO synthase and cyclooxygenase, 2) the dilations were accompanied by significant hyperpolarizations of the vascular smooth muscle (∼15 mV), and 3) the dilations were completely abolished by the calcium-activated potassium channel blocker charybdotoxin. We concluded that the role of NO in purinoceptor-induced dilations diminishes along the cerebrovascular tree in the rat, whereas the role of EDHF becomes more prominent.

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Effects of hydrogen peroxide on the responsiveness of isolated canine bronchi: role of prostaglandin E2 and I2

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.1992.263.3.l402 ◽

1992 ◽

Vol 263 (3) ◽

pp. L402-L408 ◽

Cited By ~ 10

Author(s):

Y. Gao ◽

P. M. Vanhoutte

Keyword(s):

Hydrogen Peroxide ◽

Methylene Blue ◽

Smooth Muscle ◽

Prostaglandin E2 ◽

Respiratory Epithelium ◽

Isometric Tension ◽

Third Order ◽

Bronchial Smooth Muscle ◽

Cyclic Monophosphate

The present study was design to determine the role of prostaglandin E2 and I2 in the responses of isolated canine airways to H2O2. Rings of canine third-order bronchi, some of which had undergone mechanical denudation of the epithelium, were suspended in organ chambers; isometric tension was recorded. During contractions to acetylcholine, H2O2 induced concentration-dependent relaxations. The relaxations were attenuated significantly by indomethacin, acetylsalicylic acid, and methylene blue. H2O2 increased the release of prostaglandin E2 and 6-keto-prostaglandin F1 alpha and the content of adenosine 3',5'-cyclic monophosphate (cAMP). These effects were abolished by indomethacin or methylene blue. H2O2 did not affect the content of guanosine 3',5'-cyclic monophosphate significantly. These observations suggest that 1) H2O2 relaxes canine bronchial smooth muscle and 2) elevation of tissue content of cAMP induced by prostaglandin E2 and I2 may be involved. These phenomena did not appear to be modulated by the respiratory epithelium, since H2O2-induced relaxations and increases in the release of PGE2 and 6-ketoprostaglandin F1 alpha were similar in preparations with and without epithelium. However, after treatment with methylene blue, H2O2 induced contractions only in preparations with epithelium. These epithelium-dependent contractions were not affected by inhibitors of cyclooxygenase and lipoxygenase.

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Differences in EDNO contribution to arteriolar diameters at rest and during functional dilation in striated muscle

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1993.265.1.h146 ◽

1993 ◽

Vol 265 (1) ◽

pp. H146-H151 ◽

Cited By ~ 21

Author(s):

R. L. Hester ◽

A. Eraslan ◽

Y. Saito

Keyword(s):

Striated Muscle ◽

Physiological Role ◽

Second Order ◽

Muscle Stimulation ◽

Third Order ◽

First Order ◽

Before And After ◽

Arteriolar Vasodilation ◽

Arteriolar Diameter

This study was designed to determine the physiological role of endothelium-dependent nitric oxide (EDNO) in the control of arteriolar diameter during rest and muscle stimulation. Diameters of first-, second-, and third-order arterioles in the superfused hamster cremaster muscle were measured before and throughout 1 min of field stimulation before and after inhibition of EDNO release. ENDO inhibition by intravenous N omega-nitro-L-arginine methyl ester (L-NAME) significantly attenuated the arteriolar vasodilation in response to 1 microM acetylcholine. First-order arterioles averaged 65 +/- 5 microns at rest and dilated to 86 +/- 6 microns during muscle stimulation (n = 9), second-order arterioles averaged 45 +/- 6 microns and dilated to 72 +/- 3 microns during muscle stimulation (n = 6), with third-order arterioles averaging 29 +/- 2 microns, and dilating to 53 +/- 3 microns during muscle stimulation (n = 7). EDNO inhibition significantly decreased both the resting diameter of first-order arterioles (57 +/- 4 microns) and functional dilation (68 +/- 3 microns; P <0.05). EDNO inhibition had no effect on the resting diameter of second-order arterioles (45 +/- 5 microns) yet significantly attenuated the functional dilation (64 +/- 4 microns; P < 0.05). EDNO inhibition had no effect on either the resting diameter of third-order arterioles (30 +/- 2 microns) or the functional dilation (49 +/- 2 microns).(ABSTRACT TRUNCATED AT 250 WORDS)

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