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.

The Response Of A Sense Organ To A Harmonic Stimulus

1952 ◽  
Vol 29 (2) ◽  
pp. 220-234
Author(s):  
J. W. S. PRINGLE ◽  
V. J. WILSON
Keyword(s):  
Nervous System ◽  
Transfer Function ◽  
Dynamic Properties ◽  
Sensory Nerve ◽  
Low Frequency ◽  
Sense Organ ◽  
Peak Frequency ◽  
Mechanical Stimulus ◽  
Sensory Response ◽  
Reflex Arc

1. The response is described of the tactile ending in a femoral spine of the leg of Periplaneta to a harmonic (sinusoidal) mechanical stimulus of low frequency. The peak frequency of impulses in the sensory nerve precedes the maximum tension of the stimulus. 2. This result is shown to be a corollary of the adaptation shown by the sensory response to a transient stimulus. 3. The concept of the ‘transfer function’ is discussed in relation to neurophysiology. Its value is explained as a means of describing the dynamic properties of component parts of the nervous system when the objective is an understanding of the functioning of the complete reflex arc.

scholarly journals Nucleotide Variation at theCHALCONE ISOMERASELocus inArabidopsis thaliana

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 863-872 ◽  
Author(s):  
Helmi Kuittinen ◽  
Montserrat Aguadé
Keyword(s):  
Nucleotide Diversity ◽  
Direct Relationship ◽  
Selective Sweep ◽  
Balancing Selection ◽  
Neutral Theory ◽  
Low Frequency ◽  
The Other ◽  
Nucleotide Variation ◽  
Rapid Population Growth ◽  
History Of

AbstractAn ~1.9-kb region encompassing the CHI gene, which encodes chalcone isomerase, was sequenced in 24 worldwide ecotypes of Arabidopsis thaliana (L.) Heynh. and in 1 ecotype of A. lyrata ssp. petraea. There was no evidence for dimorphism at the CHI region. A minimum of three recombination events was inferred in the history of the sampled ecotypes of the highly selfing A. thaliana. The estimated nucleotide diversity (θTOTAL = 0.004, θSIL = 0.005) was on the lower part of the range of the corresponding estimates for other gene regions. The skewness of the frequency spectrum toward an excess of low-frequency polymorphisms, together with the bell-shaped distribution of pairwise nucleotide differences at CHI, suggests that A. thaliana has recently experienced a rapid population growth. Although this pattern could also be explained by a recent selective sweep at the studied region, results from the other studied loci and from an AFLP survey seem to support the expansion hypothesis. Comparison of silent polymorphism and divergence at the CHI region and at the Adh1 and ChiA revealed in some cases a significant deviation of the direct relationship predicted by the neutral theory, which would be compatible with balancing selection acting at the latter regions.

scholarly journals 82 Struggle behavior and vocalizations of male piglets during castration

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 3-4
Author(s):  
Maria E Lou ◽  
Yuzhi Li ◽  
Beth Ventura
Keyword(s):  
Birth Weight ◽  
Acute Pain ◽  
High Frequency ◽  
Video Recording ◽  
Low Frequency ◽  
Peak Frequency ◽  
Analysis Software ◽  
Chi Square ◽  
Behavioral Indicators ◽  
Treatment Groups

Abstract Castration without the use of analgesia is routinely performed on male piglets. The objective of this study was to assess acute pain during castration through behavioral indicators. Piglets (n=88) were randomly allocated to one of two treatments: castration without the use of analgesia (C) and sham-castration (S). Within 24 hours after birth (birth weight = 1.78kg ±0.71), identical procedures were followed for both treatment groups, except sham piglets were not castrated. Struggle behavior (curl ups, leg kicks, and body flailing) and vocalizations were collected via continuous video recording as piglets received treatment from start (first application of scalpel) to end (application of iodine). Vocalization parameters (duration and peak frequency) were analyzed using the Raven Pro: Interactive Sound Analysis Software (Version 1.5). Peak frequency was defined as low (< 1000 Hz) and high (≥ 1000 Hz). Data were analyzed using the Glimmix Procedure of SAS. For struggle behavior, treatment did not affect curl up frequency. However, castrated piglets kicked more frequently than did sham piglets (C=28.8±0.9 vs. S=21.3±0.9 kicks/min; P=0.02). Additionally, 52% of castrated piglets displayed body flailing, whereas only 4.4% of sham piglets displayed the same behavior (Chi-Square = 24.2; P < 0.0001). For vocalizations, no difference was found for duration and peak frequency of low frequency calls. However, castrated piglets responded with more high frequency calls than sham piglets (C=23.6±0.3 vs. S=18.6±0.3 calls/min; P=0.04). High frequency calls tended to be of longer duration for castrated piglets (C=0.45±0.04 vs. S=0.27±0.04 sec/call; P=0.08). Results indicate that castration without the use of analgesia increased the frequency of leg kicks, body failing, and high frequency calls. This suggests that leg kicks, body flailing, and high frequency calls maybe useful behavioral indicators of acute pain in piglets.

On the Chemistry of Tetrabenzyl Thiuram Disulfide and Tetramethyl Thiuram Disulfide with Bis (Triethoxysilylpropyl) Tetrasulfide in Silica Compounds

2003 ◽  
Vol 76 (4) ◽  
pp. 876-891 ◽  
Author(s):  
R. N. Datta ◽  
A. G. Talma ◽  
S. Datta ◽  
P. G. J. Nieuwenhuis ◽  
W. J. Nijenhuis ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Succinic Anhydride ◽  
Dynamic Properties ◽  
The Other ◽  
Resonance Spectroscopy ◽  
Reaction Products ◽  
Negative Effect ◽  
Higher Temperature ◽  
Analytical Tools

Abstract The use of thiurams such as Tetramethyl thiuram disulfide (TMTD) or Tetrabenzyl thiuram disulfide (TBzTD) has been explored to achieve higher cure efficiency. The studies suggest that a clear difference exists between the effect of TMTD versus TBzTD. TMTD reacts with Bis (triethoxysilylpropyl) tetrasulfide (TESPT) and this reaction can take place even at room temperature. On the other hand, the reaction of TBzTD with TESPT is slow and takes place only at higher temperature. High Performance Liquid Chromatography (HPLC) with mass (MS) detection, Nuclear Magnetic Resonance Spectroscopy (NMR) and other analytical tools have been used to understand the differences between the reaction of TMTD and TESPT versus TBzTD and TESPT. The reaction products originating from these reactions are also identified. These studies indicate that unlike TMTD, TBzTD improves the cure efficiency allowing faster cure without significant effect on processing characteristics as well as dynamic properties. The loading of TESPT is reduced in a typical Green tire compound and the negative effect on viscosity is repaired by addition of anhydrides, such as succinic anhydride, maleic anhydride, etc.

scholarly journals Recent Observations on the Mechanical Properties of Polymer Networks

1971 ◽  
Vol 44 (5) ◽  
pp. 1256-1272 ◽  
Author(s):  
P. Thirion ◽  
R. Chasset
Keyword(s):  
Crosslink Density ◽  
Room Temperature ◽  
Dynamic Properties ◽  
Polymer Networks ◽  
The Other ◽  
Dilution Ratio ◽  
Chain Entanglement ◽  
Influence Of Temperature ◽  
Terminal Zone ◽  
Crosslinking Agents

Abstract The influence of temperature, elongation, swelling or dilution ratio, crosslink density, nature of the polymers, and crosslinking agents on the dynamic properties, creep and relaxation of polymer networks is surveyed in the terminal region of the spectrum. Whereas the deformation does not change the relaxation kinetics in large ranges of extension, the crosslink density acts as a reduced variable apparently accelerating uniformly the viscoelastic processes beyond the glass transition. The other possible reductions ‘time-temperature’ and ‘time—swelling’ do not necessarily seem related to the variations of free volume. From the viewpoint of the explanation of the relaxation mechanisms in the terminal zone, the fact that the equilibrium of loosely crosslinked elastomers would only virtually be reached after several years at room temperature seem in better agreement with chain entanglement effects, either trapped or not by the permanent network, than with the dissociation of secondary linkages.

Unusual spectral shifts in the prototropic reactions of 2,7-diaminofluorene

1987 ◽  
Vol 65 (9) ◽  
pp. 2013-2018 ◽  
Author(s):  
R. Manoharan ◽  
Sneh K. Dogra
Keyword(s):  
Absorption Spectrum ◽  
Aqueous Medium ◽  
Fluorescence Spectrum ◽  
Blue Shift ◽  
Proton Donor ◽  
Red Shift ◽  
The Other ◽  
Spectral Shifts ◽  
Other Hand

The red shift observed in the absorption spectrum of 2,7-diaminofluorene (DAF) in ether and acetonitrile is either due to the proton-donating capacity of the solute or due to its dispersive interactions with the solvent and a blue shift in methanol and water is due to the proton-accepting nature of DAF. DAF acts as a proton donor in S1 state in all solvents. The red shift in the fluorescence spectrum of the monocation of DAF relative to that of DAF is not because of the —NH2 group becoming more basic but because of the large solvent relaxating in aqueous medium. On the other hand, the monocation of DAF in cyclohexane follows the normal blue shift in the fluorescence spectrum. pKa values for the various prototropic reactions in S0 and S1 states are determined and discussed.

Investigation of Fluid Dynamic Properties of Liquid Field’s Metal

2013 ◽  
Author(s):  
Adam Lipchitz ◽  
Theophile Imbert ◽  
Glenn D. Harvel
Keyword(s):  
Numerical Modeling ◽  
Liquid Metal ◽  
Linear Dependence ◽  
Dynamic Properties ◽  
Fluid Dynamic ◽  
Weight Percent ◽  
Rotational Viscometer ◽  
Liquid States ◽  
Increasing Temperature ◽  
Solid And Liquid States

The density and viscosity Field’s metal is measured in this work and compared to traditional liquid metal coolants such as sodium and lead-bismuth eutectic. Field’s metal is a eutectic of the ternary In-Bi-Sn system. The alloy is by weight percent is 51% indium, 32.5% bismuth and 16.5% tin and possesses a melting temperature of 333 K. This work experimentally measures the density and viscosity of Field’s metal for numerical modeling and thermal hydraulic applications. The density of Field’s metal is measured using a pycnometer. The density is determined for both its solid and liquid states. In its liquid state Field’s metal is found to have a linear dependence with respect to increasing temperature. The viscosity of Field’s metal is measured using a rotational viscometer. The viscosity is measured is to be 27 mPa-s at 353 K, however further investigation is required to determine a trend at higher temperatures.

Temperature Dependent Raman Scattering in CsTiOAsO4 Single Crystal

1995 ◽  
Vol 398 ◽  
Author(s):  
A.R. Guo ◽  
C.-S. Tu ◽  
Ruiwu Tao ◽  
R.S. Katiyar ◽  
Ruyan Guo ◽  
...  
Keyword(s):  
Soft Mode ◽  
Low Frequency ◽  
High Mobility ◽  
Vibrational Modes ◽  
Frequency Range ◽  
Temperature Dependent ◽  
Higher Symmetry ◽  
Phonon Spectra ◽  
Symmetry Structure ◽  
Increasing Temperature

ABSTRACTThe longitudinal (LO) and transverse (TO) A1 vibrational modes have been measured between 30-1200 cm−1 as a function of temperature (30–1240 K) for CsTiOAsO4 (CTA). The frequencies for all corresponding Raman components shifted to lower frequencies on increasing the temperature, however, there is no typical soft-mode like behavior observed in the measured frequency range. The relative intensities of the low frequency bands increase dramatically with increasing temperature due to high mobility of Cs+ ion. A higher symmetry structure taking place above 940K has been confirmed by changes in the phonon spectra.

scholarly journals Diversity of and Selection Acting on CylindrospermopsincyrBGene Adenylation Domain Sequences in Florida

2011 ◽  
Vol 77 (7) ◽  
pp. 2502-2507 ◽  
Author(s):  
Mete Yilmaz ◽  
Edward J. Phlips
Keyword(s):  
United States ◽  
Low Frequency ◽  
Purifying Selection ◽  
The United States ◽  
The Other ◽  
Cylindrospermopsis Raciborskii ◽  
Adenylation Domain ◽  
Other Hand ◽  
Neutrality Tests ◽  
The One

ABSTRACTAphanizomenon ovalisporumis the only confirmed cylindrospermopsin producer identified in the United States to date. On the other hand,Cylindrospermopsis raciborskiiis a prominent feature of many lakes in Florida and other regions of the United States. To see the variation in cylindrospermopsincyrBgene adenylation domain sequences and possibly discover new cylindrospermopsin producers, we collected water samples for a 3-year period from 17 different systems in Florida. Positive amplicons were cloned and sequenced, revealing that approximately 92% of sequences wereA. ovalisporum-like (>99% identity). Interestingly, 6% of sequences were very similar (>99% identity) tocyrBsequences ofC. raciborskiifrom Australia and ofAphanizomenonsp. from Germany. Neutrality tests suggest thatA. ovalisporum-likecyrBadenylation domain sequences are under purifying selection, with abundant low-frequency polymorphisms within the population. On the other hand, when compared between species by codon-based methods, amino acids of CyrB also seem to be under purifying selection, in accordance with the one proposed amino acid thought to be activated by the CyrB adenylation domain.

scholarly journals The role of word frequencies in detecting unfamiliar terms and their effect on response quality

Psihologija ◽  
2015 ◽  
Vol 48 (4) ◽  
pp. 327-344 ◽  
Author(s):  
Ana Slavec ◽  
Vasja Vehovar
Keyword(s):  
Low Frequency ◽  
Drop Out ◽  
The Other ◽  
International Exchange ◽  
Subjective Perception ◽  
Exchange Students ◽  
Text Corpora ◽  
Drop Out Rate ◽  
The University

Research into cognitive aspects of survey response has indicated unfamiliar terms as one of the psycholinguistic determinants of question comprehensibility problems. In this paper the estimates of wording familiarity based on text corpora for the English and Slovenian languages were used to detect potentially incomprehensible wordings in two web survey questionnaires for international exchange students at the University of Ljubljana, one for incoming (English) and the other for outgoing students (Slovenian). Two versions of the questionnaire were developed for each language, one with low-frequency (complex) and the other with high-frequency (improved) wordings, and compared in a split-ballot experiment. The results show a lower drop-out rate and a decreased subjective perception of difficulty for the improved language versions.

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