scholarly journals Nanomechanical Molecular Mass Sensing Using Suspended Microchannel Resonators

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3337
Author(s):  
Alberto Martín-Pérez ◽  
Daniel Ramos ◽  
Javier Tamayo ◽  
Montserrat Calleja
Keyword(s):  
Molecular Mass ◽  
Mass Density ◽  
Applied Pressure ◽  
Atomic Mass ◽  
Liquid Sample ◽  
Mass Sensing ◽  
Average Molecular Mass ◽  
Fluid Properties ◽  
Molecular Masses ◽  
Microchannel Resonators

In this work we study the different phenomena taking place when a hydrostatic pressure is applied in the inner fluid of a suspended microchannel resonator. Additionally to pressure-induced stiffness terms, we have theoretically predicted and experimentally demonstrated that the pressure also induces mass effects which depend on both the applied pressure and the fluid properties. We have used these phenomena to characterize the frequency response of the device as a function of the fluid compressibility and molecular masses of different fluids ranging from liquids to gases. The proposed device in this work can measure the mass density of an unknown liquid sample with a resolution of 0.7 µg/mL and perform gas mixtures characterization by measuring its average molecular mass with a resolution of 0.01 atomic mass units.

Characterization of dissolved material during the initial phase of softwood kraft pulping

TAPPI Journal ◽  
2013 ◽  
Vol 12 (1) ◽  
pp. 37-43 ◽  
Author(s):  
HANNU PAKKANEN ◽  
TEEMU PALOHEIMO ◽  
RAIMO ALÉN
Keyword(s):  
Mass Transfer ◽  
Molecular Mass ◽  
Initial Phase ◽  
Degradation Products ◽  
Kraft Pulping ◽  
Reaction Products ◽  
Cooking Temperature ◽  
Molecular Masses ◽  
Aliphatic Carboxylic Acids

The influence of various cooking parameters, such as effective alkali, cooking temperature, and cooking time on the formation of high molecular mass lignin-derived and low molecular mass carbohydrates-derived (aliphatic carboxylic acids) degradation products, mainly during the initial phase of softwood kraft pulping was studied. In addition, the mass transfer of all of these degradation products was clarified based on their concentrations in the cooking liquor inside and outside of the chips. The results indicated that the degradation of the major hemicellulose component, galactoglucomannan, typically was dependent on temperature, and the maximum degradation amount was about 60%. In addition, about 60 min at 284°F (140°C) was needed for leveling off the concentrations of the characteristic reaction products (3,4-dideoxy-pentonic and glucoisosaccharinic acids) between these cooking liquors. Compared with low molecular mass aliphatic acids, the mass transfer of soluble lignin fragments with much higher molecular masses was clearly slower.

Extraction of polyethylene glycols with dicarbolide solutions in nitrobenzene

1990 ◽  
Vol 55 (8) ◽  
pp. 1959-1967 ◽  
Author(s):  
Petr Vaňura ◽  
Pavel Selucký
Keyword(s):  
Polyethylene Glycol ◽  
Molecular Mass ◽  
Extraction Constant ◽  
Metal Extraction ◽  
Polyethylene Glycols ◽  
Relative Molecular Mass ◽  
Published Data ◽  
Average Molecular Mass ◽  
Peg 400 ◽  
Extraction Constants

The extraction of polyethylene glycol of average molecular mass 400 (PEG 400) with dicarbolide solution in nitrobenzene and of longer-chain polyethylene glycol, of average molecular mass 1 500 (PEG 1 500), with chlorinated dicarbolide solution in nitrobenzene was studied. During the extraction of PEG 400, the polyethylene glycol solvates the Horg+ ion in the organic phase giving rise to the HLorg+ species (L is polyethylene glycol). The obtained value of the extraction constant Kex(HLorg+) = 933 is consistent with published data of metal extraction. Extraction of PEG 1 500 was treated applying the simplified assumption that the thermodynamic behaviour of PEG 1 500 is the same as that of n molecules of polyethylene glycol with relative molecular mass 1 500/n, each solvating one cation. For this model, the value of n = 3.2 ± 1.1 and the values of the extraction constants of the HL1/n,org+ and HL2/n,org+ species were obtained by using the adapted program LETAGROP. This value of n is consistent with published extraction data in the presence of polyethylene glycol with a relative molecular mass from 200 to 1 000.

scholarly journals Identification of two highly sialylated human tear-fluid DMBT1 isoforms: the major high-molecular-mass glycoproteins in human tears

2002 ◽  
Vol 366 (2) ◽  
pp. 511-520 ◽  
Author(s):  
Benjamin L. SCHULZ ◽  
David OXLEY ◽  
Nicolle H. PACKER ◽  
Niclas G. KARLSSON
Keyword(s):  
Molecular Mass ◽  
Peptide Mass Fingerprinting ◽  
High Molecular Mass ◽  
Tear Fluid ◽  
Protein Variant ◽  
Peptide Mass ◽  
Composite Gel ◽  
Molecular Masses ◽  
Protein Components ◽  
Sialyl Lea

Human open eye tear fluid was separated by low-percentage SDS/PAGE to detect high-molecular-mass protein components. Two bands were found with apparent molecular masses of 330 and 270kDa respectively. By peptide-mass fingerprinting after tryptic digestion, the proteins were found to be isoforms of the DMBT1 gene product, with over 30% of the predicted protein covered by the tryptic peptides. By using gradient SDS/agarose/polyacrylamide composite gel electrophoresis and staining for glycosylation, it was shown that the two isoforms were the major high-molecular-mass glycoproteins of >200kDa in human tear fluid. Western blotting showed that the proteins expressed sialyl-Lea. After the release of oligosaccharides by reductive β-elimination from protein blotted on to PVDF membrane, it was revealed by liquid chromatography-MS that the O-linked oligosaccharides were comprised mainly of highly sialylated oligosaccharides with up to 16 monosaccharide units. A majority of the oligosaccharides could be described by the formula dHex0→2NeuAc1→xHexxHexNAcx(-ol), x = 1–6, where Hex stands for hexose, dHex for deoxyhexose, HexNAc for N-acetylhexosamine and NeuAc for N-acetylneuraminate. The number of sialic acids in the formula is less than 5. Interpretation of collision-induced fragmentation tandem MS confirmed the presence of sialic acid and suggested the presence of previously undescribed structures carrying the sialyl-Lea epitopes. Small amounts of neutral and sulphated species were also present. This is the first time that O-linked oligosaccharides have been detected and described from protein variant of the DMBT1 gene.

scholarly journals Physical properties of surfaces. II—Viscous flow of liquid films. The range of action of surface forces

1935 ◽  
Vol 151 (872) ◽  
pp. 220-233 ◽  
Author(s):  
S. H. Bastow ◽  
Frank Philip Bowden ◽  
Thomas Martin Lowry
Keyword(s):  
Viscous Flow ◽  
Freezing Point ◽  
Applied Pressure ◽  
Liquid Films ◽  
Appreciable Effect ◽  
Straight Line Passing ◽  
Straight Line ◽  
Fluid Properties ◽  
Line Passing ◽  
Induced Structure

The present paper describes experiments which were carried out in order to determine the extent to which the fluid properties of water and other liquids may be modified by the presence of a solid surface. For this purpose, measurements of the viscous flow of a liquid very near to a surface are particularly suitable, since they provide a sensitive test for the existence of any induced structure in the liquid. If the surface has no appreciable effect, the smallest applied pressure will cause the liquid to flow and the rate of flow plotted against pressure will give a straight line passing through the origin, see fig. 3. If, however, as many authors have suggested, long chains of oriented liquid molecules with a definite rigidity are formed by the influence of the surface, the liquid will show a resistance to shear, which will be specially evident at low pressures; Poiseuille’s law will not hold and the pressure-flow curve will be of the form shown in fig. 4. A method has been developed for measuring the viscosity of thin liquid films enclosed between flat polished surfaces of glass and steel. The film thickness can be varied from about 10 -5 cm to any desired distance and can be accurately determined. The experiments show that films of a liquid, known to possess a bulk structure (liquid crystal), possess a high rigidity, but there is no sign of induced structure in normal liquids even with very thin films and at temperatures near the freezing point.

Dynamic computed tomography with low- and high-molecular-mass contrast agents to assess microvascular permeability modifications in a model of liver fibrosis

2002 ◽  
Vol 103 (2) ◽  
pp. 213-216 ◽  
Author(s):  
Roland MATERNE ◽  
Laurence ANNET ◽  
Stéphane DECHAMBRE ◽  
Christine SEMPOUX ◽  
Anne M. SMITH ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Contrast Agents ◽  
Molecular Mass ◽  
Hepatic Fibrosis ◽  
Mean Transit Time ◽  
Distribution Volume ◽  
High Molecular Mass ◽  
Permeability Changes ◽  
Molecular Masses ◽  
The Mean

Interstitial collagen formation and transformation of the fenestrated hepatic sinusoids into continuous capillaries are major ultrastructural changes that occur in liver cirrhosis and fibrosis. These modifications lead to progressive restriction of blood–liver exchanges. The purpose of our study was to evaluate the permeability changes in a model of hepatic fibrosis by using dynamic computed tomography (CT) enhanced with contrast agents of different molecular masses. Dynamic single-section CT of the liver was performed after intravenous bolus administration of a low-molecular-mass contrast agent (iobitridol) and an experimental high-molecular-mass agent (P840) in normal control rabbits and in rabbits with hepatic fibrosis. Hepatic, aortic and portal venous time–density curves were fitted with a dual-input one-compartmental model to calculate the hepatic mean transit time and distribution volume of the contrast agents. In the rabbits with liver fibrosis, the mean transit time of the high-molecular-mass agent was shorter than that of the low-molecular-mass agent (10.0±1.8s and 12.0±1.2s respectively; P<0.05). The distribution volume accessible to the high-molecular-mass agent was also smaller (22.2±4.8% compared with 32.0±6.7%; P<0.01). In the normal rabbits, the mean transit times of the high- and low-molecular-mass agents did not differ significantly, and nor did their distribution volumes. Our results demonstrate decreased sinusoidal permeability for the high-molecular-mass agent P840 in a model of hepatic fibrosis. Non-invasive assessment of permeability changes in liver fibrosis can be performed with dynamic CT and contrast agents of different molecular masses.

scholarly journals Mass spectrometric analysis of rat liver cytosolic glutathione S-transferases: modifications are limited to N-terminal processing

1995 ◽  
Vol 308 (1) ◽  
pp. 69-75 ◽  
Author(s):  
H I Yeh ◽  
C H Hsieh ◽  
L Y Wang ◽  
S P Tsai ◽  
H Y Hsu ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Female Rats ◽  
Spectrometric Analysis ◽  
Affinity Column ◽  
Female Rat ◽  
Significant Difference ◽  
Cytosolic Glutathione ◽  
Glutathione S Transferases ◽  
Molecular Masses ◽  
Rat Livers

Cytosolic glutathione S-transferases (GSTs) from rat livers were purified using an S-hexylglutathione affinity column. The GST subunits were resolved by reverse-phase HPLC and their molecular masses were determined by electrospray mass spectrometry. The major hepatic GSTs detected were subunits 1, 1′, 2, 3 and 4, with molecular mass of 25,520, 25,473, 25,188, 25,782 and 25,571 Da respectively. Subunits 6, 7 and 10 are minor components, with molecular mass of 25,551, 23,308 and 25,211 Da respectively. Alternatively, the hepatic GSTs were purified using a glutathione affinity column. Subunits 1, 1′, 2, 8 and 10 were eluted from this column with GSSG, the oxidized form of glutathione. Subunit 8 has a molecular mass of 25,553 Da. The remaining proteins on the glutathione affinity column were removed with glutathione and S-hexylglutathione. Subunits 2, 3, 4 and 6 could be detected in the eluate. We could not detect any significant difference in molecular mass between GSTs isolated from male and female rat livers. Cytosolic GSTs were isolated from livers of buthionine sulphoximine-treated female rats for MS analysis. The molecular masses obtained were identical to those determined for the controls.

The static electrifications of linear flexible-chain polymers extruded through ducts above the glass transition temperature

1987 ◽  
Vol 409 (1837) ◽  
pp. 249-270 ◽  
Keyword(s):  
Molecular Mass ◽  
Anionic Polymerization ◽  
Chemical Nature ◽  
Molecular Mass Distribution ◽  
Relaxation Transition ◽  
Sliding Velocity ◽  
Flexible Chain ◽  
Mass Distributions ◽  
Static Electrification ◽  
Molecular Masses

A study has been made into electrification of linear flexible-chain polymers extruded through metal and dielectric ducts. Most of the work concerns 1,4-polybutadienes prepared by anionic polymerization, with different molecular masses and molecular mass distributions. A pre-requisite for intense static electrification is the relaxation transition of the polymer from fluid into forced high-elastic state in which the polymer slides over the duct wall surface. The relation between electrification of polymers and their molecular mass, molecular-mass distribution, temperature, sliding velocity, and the duct length has been established. Electrification of polybutadiene in dielectric ducts and the effect of the chemical nature of polymers on their static electrification were also examined.

scholarly journals Levan-Producing Leuconostoc citreum Strain BD1707 and Its Growth in Tomato Juice Supplemented with Sucrose

2015 ◽  
Vol 82 (5) ◽  
pp. 1383-1390 ◽  
Author(s):  
Jin Han ◽  
Xiaofen Xu ◽  
Caixia Gao ◽  
Zhenmin Liu ◽  
Zhengjun Wu
Keyword(s):  
Molecular Mass ◽  
Sugar Content ◽  
Carbon Sources ◽  
Viable Cell ◽  
Monosaccharide Composition ◽  
Tomato Juice ◽  
Average Molecular Mass ◽  
Content Type ◽  
Leuconostoc Citreum ◽  
Sucrose Medium

ABSTRACTA levan-producing strain, BD1707, was isolated from Tibetan kefir and identified asLeuconostoc citreum. The effects of carbon sources on the growth ofL. citreumBD1707 and levan production in tomato juice were measured. The changes in pH, viable cell count, sugar content, and levan yield in the cultured tomato juice supplemented with 15% (wt/vol) sucrose were also assayed.L. citreumBD1707 could synthesize more than 28 g/liter of levan in the tomato juice-sucrose medium when cultured at 30°C for 96 h. Based on the monosaccharide composition, molecular mass distribution, Fourier transform infrared (FTIR) spectra, and nuclear magnetic resonance (NMR) spectra, the levan synthesized byL. citreumBD1707 was composed of a linear backbone consisting of consecutive β-(2→6) linkedd-fructofuranosyl units, with an estimated average molecular mass of 4.3 × 106Da.

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