Revealing unfolding steps and volume changes of human telomeric i-motif DNA

2020 ◽  
Vol 22 (41) ◽  
pp. 23816-23823 ◽  
Author(s):  
Judit Somkuti ◽  
Orsolya Réka Molnár ◽  
László Smeller

The i-motif structure of the human telomeric DNA was destabilized by pressure and unfolded with a negative volume change.

2012 ◽  
Vol 706-709 ◽  
pp. 2290-2295 ◽  
Author(s):  
M. J. Santofimia ◽  
Lie Zhao ◽  
Jilt Sietsma

Annealing of martensite/austenite microstructures leads to the partitioning of carbon from martensite to austenite until the chemical potential of carbon equilibrates in both phases. This work calculates the volume change associated with this phenomenon using theoretical models for the carbon partitioning from martensite to austenite. Calculations are compared with experimentally determined volume changes. This comparison reveals that in the case of steels with higher contents of austenite-stabilizing elements, reported volume changes are satisfactory predicted assuming a low mobilily martensite/austenite interface. In the case of a steel with lower additions of austenite-stabilizing elements, experimentally measured expansions are considerably larger than predicted ones. The large measured volume expansions probably reflect the decomposition of the austenite.


1950 ◽  
Vol 27 (3) ◽  
pp. 334-349
Author(s):  
PETER TUFT

A new micro-respirometer is described, capable of measuring rates of volume change from 5 µl./hr. down to 0.01 µl./hr. to the nearest 0.001 µl. It is a constant-pressure nul-reading instrument and the actual volumes of gas absorbed or evolved are obtained from readings of the instrument by a simple multiplication. A device is described which sets the instrument automatically and records the volume changes at regular intervals.


1989 ◽  
Vol 257 (1) ◽  
pp. H38-H46 ◽  
Author(s):  
K. B. Campbell ◽  
A. R. Rahimi ◽  
D. L. Bell ◽  
R. D. Kirkpatrick ◽  
J. A. Ringo

Observed pressure responses to quick volume changes in the isolated tetanized heart of ferrets were compared with previously reported tension responses to quick length changes in isolated cardiac muscle. Hearts were isolated from ferrets, perfused with ryanodine solution, and stimulated rapidly (50 ms between stimulations) to produce repeated 4-s intervals of tetanus. During each tetanus interval, volume increments of different amplitudes were rapidly removed and then reinfused into the left ventricular chamber. The pressure responses to these volume changes were evaluated for differences between withdrawals and infusions and for dependence on the amplitude of the volume change. It was found for both withdrawal and infusion that the response could be divided into three phases: 1) an immediate phase coincident with volume change, 2) a fast-recovery phase, and 3) a slow-recovery phase. The amplitude of the immediate phase was linearly dependent on the volume change so that a single regression line fit all the data (withdrawal and infusion). The fast recovery phase was 2.5 times faster for infusion than for withdrawal and generated a rebound effect with the pressure going below the initial pressure in the response to infusion. The pressure never went above the initial pressure in the response to withdrawal. The slow-recovery phases in infusion and withdrawal did not differ. These responses in the isolated heart bear striking similarities to tension responses to quick length changes in isolated constantly activated cardiac muscle. We concluded that muscle fiber dynamics were being faithfully transformed to left ventricular (LV) chamber dynamics without appreciable distortion because of the many intervening factors between the wall muscle fiber and the LV chamber.(ABSTRACT TRUNCATED AT 250 WORDS)


2002 ◽  
Vol 39 (3) ◽  
pp. 757-764 ◽  
Author(s):  
C W.W Ng ◽  
L T Zhan ◽  
Y J Cui

A new simple system for accurately measuring overall total volume changes in unsaturated soil specimens with a triaxial apparatus is introduced in this paper. The basic principle of the measuring system is to record changes in the differential pressure due to changes in the water level inside an open-ended, bottle-shaped inner cell caused by volume change in the specimen and inside a reference tube using an accurate differential pressure transducer. Several important steps were taken to improve the accuracy and sensitivity of the measuring system. Detailed calibrations were carried out to account for apparent volume changes as a result of changes in cell pressure, fluctuation in the ambient temperatures, creep in the inner cell wall, and relative movement between the loading ram and the inner cell. The calibration results demonstrate that the measuring system is reasonably linear, reversible, and repeatable. The estimated accuracy of the measuring system is in the order of 32 mm3 (or 0.04% volumetric strain for a triaxial specimen 38 mm in diameter and 76 mm in height) once the system is properly calibrated.Key words: unsaturated soils, volume-change measurement, open-ended, bottle-shaped, inner cell, differential pressure, calibration.


2020 ◽  
pp. 074880682098086
Author(s):  
Robert T. Cristel ◽  
Benjamin P. Caughlin

Buccal fat pad sculpting and removal (BFPS) can create narrowing of the lower 1/3rd of the face by selective removal and reduction of soft tissue volume. Three-dimensional (3D) imaging allows for quantitative and objective assessment of volume changes over traditional 2-dimensional photographs that has not been previously studied in BFPS. A prospective study was designed in consecutive subjects undergoing BFPS from April 2018 through March 2020. Only those patients that underwent solely BFPS were included. VectraXT 3D imaging and software was used to compare preoperative and postoperative volume changes. Fifteen patients were enrolled in the study with 2 males and 13 females. The mean length of follow up was 7.7 months (range: 1-21 months). All patients were found to have volume reduction in the area evaluated. The mean volume reduction of the selected mid-lower face in the frontal view was 7.2 mL on the left side and 7.5 mL on the right side. There was no statistical difference between the volume change when the 2 sides were compared (P= 0.82). This study demonstrate the use of 3D photography to objectively and quantitatively assess volume change following BFPS and that the volume removed is significant enough to demonstrate favorable results using 3D imaging. Buccal fat pad sculpting is a safe and reliable option for creating a narrowed lower one-third of the face. This is accomplished by selective fat removal and cautery induced reduction of the lower one-third of the face soft tissue volume. VectraXT 3D imaging and analysis is a powerful tool to objectively and quantitatively assess volume changes in BFPS.


1969 ◽  
Vol 15 (8) ◽  
pp. 933-940 ◽  
Author(s):  
Robert E. Marquis ◽  
Wallace O. Fenn

A simply constructed dilatometer or volumeter was used to measure small volume changes (ca. 6 × 10−4 ml per milliliter) accompanying growth of Streptococcus faecalis cultures. Polymerization reactions involved in cell synthesis appeared to contribute little to the observed changes, and dilatation of cultures in glucose-containing media could be interpreted mainly in terms of volume changes associated with cleavage of glucose to lactic acid, ionization of lactic acid, and protonation of buffer ions in the culture. Glycolysis in suspensions of nongrowing cells was accompanied by similar increases in volume. In contrast, arginine degradation by S. faecalis was accompanied by contraction, and in this case the volume change could be almost completely accounted for by differences in partial molar volumes of products and reactants. Possible relationships between metabolic volume changes and pressure sensitivity of bacteria are discussed.


1998 ◽  
Vol 44 (148) ◽  
pp. 570-582 ◽  
Author(s):  
G. Adalgeirsdóttir ◽  
K. A. Echelmeyer ◽  
W. D. Harrison

AbstractAirborne surface elevation profiles of the Harding Ice field, south-central Alaska, were made in 1991 and 1996. Thirteen glaciers were profiled, along with the tipper region of the icefield. The profiles were compared to U.S. Geological Survey topographie maps made in the 1950s, to obtain elevation and volume changes. Comparison of the changes for the different glaciers shows no significant correlation between volume change and the type of glacier or characteristics such as location, aspect, size, slope or terminus changes. Estimated total volume change tor this ~43 year period is about -34 km3, which corresponds to an area-average elevation change of-21 m. The estimated error in this elevation change of 5 m is mainly due to errors in the maps at higher elevations. Our measurements provide an accurate baseline against which future determinations of volume change can be made.


1998 ◽  
Vol 53 (9) ◽  
pp. 787-792
Author(s):  
M. Sandmann ◽  
A. Würflinger

Abstract P, Vm , Tdata have been measured for the smectic, nematic and isotropic phases of 4'-n-octyl-biphen-yl-4-carbonitrile (8CB) in the temperature range 300-370 K and pressures up to 300 MPa. At atmospheric pressure all phase transitions appear to be of first order due to a discontinuity in the density. The volume change at the smectic A -nematic transition is only a tenth of the volume change at the clearing temperature. At moderate pressures below 80 MPa the SA -N transition could be detected as a discontinuity in the period of oscillation in measurements with a high-pressure vibrating tube densimeter. At higher pressures the discontinuity seems to die away, possibly indicating a change from first order to second order transition. From the volume changes and the slopes of the transition lines we calculate the enthalpy changes at the phase transition. The p, Vm , T data enable us to calculate the volume part of the entropy and the molecular field parameter γ=δln TNI/δln VNI .


Nature ◽  
2004 ◽  
Vol 428 (6982) ◽  
pp. 545-549 ◽  
Author(s):  
Haemyeong Jung ◽  
Harry W. Green II ◽  
Larissa F. Dobrzhinetskaya

1962 ◽  
Vol 14 (3) ◽  
pp. 445-458 ◽  
Author(s):  
Howard G. Davies ◽  
Michael Spencer

Observations have been made on the role of a divalent cation (calcium ion) during OsO4 fixation of nuclei of frog erythrocytes, mainly after isolation from cells. The volume of the nucleus depends partly on the molecular interaction of charged macromolecules, is controlled by the ionic strength of the medium, and hence may be used as a guide in attempts to preserve structure. When the isolation and fixation media contain 0.01 M calcium at pH 6.3 the volume changes, in the light microscope, during processing are small. When the fixative does not contain these ions, reversible volume changes occur during fixation and dehydration. The chromatin of nuclei processed with minimal volume change appears, in the electron microscope, to contain fine dots and lines about 20 to 40 A in diameter, relatively close together. The chromatin structure of nuclei in which volume changes have occurred consists of dense irregularly shaped patches, relatively far apart, and ranging in diameter from about 200 A down to the limits of visibility (20 to 30 A). It is suggested that the latter structure is a precipitation artefact.


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