Dimensional changes in Corsican pine (Pinus nigra Arnold) modified with acetic anhydride measured using a helium pycnometer

Holzforschung ◽  
2004 ◽  
Vol 58 (5) ◽  
pp. 544-547 ◽  
Author(s):  
Callum A.S. Hill ◽  
Graham A. Ormondroyd
Keyword(s):  
Cell Wall ◽  
Acetic Anhydride ◽  
Linear Relationship ◽  
Volume Change ◽  
Pinus Nigra ◽  
Weight Percentage ◽  
Dimensional Changes ◽  
Percentage Volume ◽  
The Difference ◽  
Helium Pycnometry

Abstract Helium pycnometry was used to determine the changes in volume of wood samples of Corsican pine following modification with acetic anhydride. Results were compared with changes in volume determined from external dimensions only. Percentage change in volume, as determined from external dimensions of the sample, showed a non-linear relationship with weight percentage gain as a result of acetylation; whereas percentage volume change determined by helium pycnometry showed a linear relationship. The difference in volume as determined by the two methods is explained by considering volume change of the lumens as level of cell wall substitution increases. Results obtained in this study show that volume increases due to chemical modification, when determined by measurement of external dimensions, should not be used to evaluate changes in cell wall volume.

Changes in the cell wall volume of a number of wood species due to reaction with acetic anhydride

Holzforschung ◽  
2007 ◽  
Vol 61 (2) ◽  
pp. 138-142 ◽  
Author(s):  
Jin H. Kwon ◽  
Callum A.S. Hill ◽  
Graham A. Ormondroyd ◽  
Siti Karim
Keyword(s):  
Cell Wall ◽  
Acetic Anhydride ◽  
Molar Volume ◽  
Volume Change ◽  
Wood Species ◽  
Korean Pine ◽  
Volume Changes ◽  
Weight Percentage ◽  
Acetyl Group ◽  
Helium Pycnometry

Abstract A number of softwoods and hardwoods (beech, rubberwood, Corsican pine, Korean pine) were reacted with acetic anhydride to a variety of weight percentage gain (WPG) values and the volume change due to reaction was determined both by measurement of the external dimensions and by helium pycnometry. The volume change due to modification determined by helium pycnometry was found to be equal to that calculated, except for Corsican pine. The volume change as determined by the external dimensions was not a reliable method for determining cell-wall volume changes. The molar volume of the acetyl group in the cell wall was calculated over a range of WPG values, with volumes ranging from approximately 32 to 42 cm3 mol-1, depending on the wood species studied. The differences in acetyl molar volume observed between most wood species were significant.

Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

1997 ◽  
Vol 161 ◽  
pp. 491-504 ◽  
Author(s):  
Frances Westall
Keyword(s):  
Cell Wall ◽  
Life Forms ◽  
Cation Binding ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Hydrothermal Sediments ◽  
Identification Of Bacteria ◽  
The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

Acetyl Group Distribution in Acetylated Wood Investigated by Microautoradiography

Holzforschung ◽  
2001 ◽  
Vol 55 (3) ◽  
pp. 270-275 ◽  
Author(s):  
Marie Rosenqvist
Keyword(s):  
Cell Wall ◽  
Weight Gain ◽  
Acetic Anhydride ◽  
Wood Cell Wall ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Accurate Information ◽  
Concentration Gradients ◽  
Good Opportunity ◽  
Acetyl Group

Summary Sapwood of Scots pine (Pinus silvestris L.) was acetylated with 14C- and 3H-labelled acetic anhydride. The distribution of acetyl groups was investigated with microautoradiography and microautoradiographs were evaluated with ESEM, Environmental Scanning Electron Microscopy. The investigation showed that the impregnation of wood with radioisotope-labelled substances provides a good opportunity to investigate the location of substances covalently bonded to the wood material. Introduced 14C-labelled acetyl groups show an even distribution in the wood cell wall, with no discernible concentration gradients at acetylation levels of about 5, 15 and 20% weight gain. 3H-labelled acetyl groups show an even distribution in the wood cell wall at 15 and 20% weight gain, with no discernible concentration gradients. At the 5% weight gain level, however, an uneven distribution of 3H-labelled acetyl groups over the cell wall is observed. Nevertheless, the unevenness is random and no concentration gradient is discernible at this level. 3H with a relatively high resolution, 0.5–1 μm, compared to 14C with a resolution of 2–5 μm, gives more accurate information about where exactly the acetyl groups are situated in the wood cell wall. Acetic anhydride was evenly distributed when a full impregnation procedure was used. The chemical and physical properties of acetic anhydride allow a uniform penetration into the pine cell wall and a complete acetylation takes place when the specimens are heated.

An assessment of the quality of forage from its cell-wall content and amount of cell wall digested

1972 ◽  
Vol 78 (3) ◽  
pp. 355-362 ◽  
Author(s):  
K. W. Moir
Keyword(s):  
Cell Wall ◽  
Organic Matter ◽  
Ammonium Oxalate ◽  
Physical Structure ◽  
Tropical Species ◽  
Average Amount ◽  
Lignin Concentration ◽  
Digestible Organic Matter ◽  
The Difference

SUMMARYGrasses and legumes comprising poor to good quality temperate and tropical species were fed to either cattle or sheep in 36 digestibility experiments. Cell wall in these forages was the ash-free and protein-free residue after sequential extraction with acidpepsin, organic solvents and either water for grasses or ammonium oxalate for legumes. The average amount of cell wall digested per 100 g forage OM was 40·0±0·59 g in grasses and 19·8±1·85 g in legumes. It was considered that within grasses and within legumes the physiology of ruminant digestion, rather than forage quality, was the main determinant of the average amount of cell wall digested and the difference between grasses and legumes was due to interaction of the ruminant digestion process with the physical structure of the cell wall. Of forage factors governing variation about the physiological average, the total cell wall had some effect on the amount of cell wall digested, but the lignin concentration in the cell wall had no effect.Among grasses and legumes the average, apparently undigested, protein-free non-cell-wall component was 6·2±0·13 g per 100 g forage OM. This component and digestible protein relative to total protein varied among different sets of data. It was concluded that only the component of digestible organic matter which was governed by the relative proportions of cell walls and cellular contents was predictable from chemical composition. It was considered that selection in plant breeding should be based on both digestible cell wall and cell-wall content instead of digestible organic matter.

Static Pressure-Volume Curves for the Lung of the Frog (Rana Pipiens)

1978 ◽  
Vol 76 (1) ◽  
pp. 149-165 ◽  
Author(s):  
G. M. HUGHES ◽  
G. A. VERGARA
Keyword(s):  
Volume Change ◽  
Rana Pipiens ◽  
Static Pressure ◽  
Large Diameter ◽  
The Difference ◽  
Isolated Lungs ◽  
Precise Role ◽  
Different Parts

1. Static pressure/volume curves have been determined for isolated frog lungs inflated with either air or saline. In both cases a hysteresis was present: the pressure required to produce unit change of volume being greater during inflation than deflation. 2. The pressure necessary for a given volume change was less for the saline-filled than the air-filled lungs. The difference between these curves is due to the surface tension at the air/lung interface. 3. Pressure/volume curves for air-filled lungs in situ were similar to curves for isolated lungs. However, a greater pressure was required for the same volume change during both inflation and deflation. 4. Compliance was calculated from different parts of air pressure/volume curves and gave values greater than those obtained using similar calculations for higher vertebrates. 5. These observations support other evidence for the presence of a surfactant in the lung lining of frogs in spite of the relatively large diameter of their ‘alveoli.’ The precise role of such a lining is uncertain and it is concluded that similar forces may be involved during the inflation and deflation of lungs of frogs and higher vertebrates in spite of differences in gross morphology.

CELL-WALL LIGNIN CONTENT RELATED TO TRACHEID DIMENSIONS IN DROUGHT-SENSITIVE AUSTRIAN PINE (PINUS NIGRA)

IAWA Journal ◽  
2001 ◽  
Vol 22 (2) ◽  
pp. 113-120 ◽  
Author(s):  
Wolfgang Gindl
Keyword(s):  
Cell Wall ◽  
Lignin Content ◽  
Water Status ◽  
Pinus Nigra ◽  
Lignin Concentration ◽  
Wall Area ◽  
Pine Tree ◽  
Cell Dimensions ◽  
Highly Correlated ◽  
Annual Distribution

The intra-annual distribution of cell-wall lignin concentration was determined in Austrian pine tree rings and compared with tracheid diameter, lumen width, cell wall thickness and proportion of cell wall area. Lignin concentration was highly correlated with all tracheid dimensions, but only the proportion of cell wall area exhibited a direct statistically significant relationship. Since cell dimensions in Austrian pine are subjected to the indirect and direct influences of the water status of trees, the negative correlation between cellular lignin content and the proportion of cell wall area is attributed to an indirect effect of water stress on lignification in pine tracheids.

scholarly journals Differences in cell wall of thin and thick filaments of cyanobacterium Aphanizomenon gracile SAG 31.79 and their implications for different resistance to Daphnia grazing

2016 ◽  
Author(s):  
Lukasz Wejnerowski ◽  
Slawek Cerbin ◽  
Maria K. Wojciechowicz ◽  
Marcin K. Dziuba
Keyword(s):  
Cell Wall ◽  
Wall Thickness ◽  
Cell Walls ◽  
Cell Wall Thickness ◽  
Filamentous Cyanobacterium ◽  
Thin Sections ◽  
Thick Filaments ◽  
Transmission Electron ◽  
The Difference ◽  
Aphanizomenon Gracile

<p>Recent studies have shown that the filamentous cyanobacterium <em>Aphanizomenon gracile</em> Lemmermann, strain SAG 31.79, consists of two types of filaments that differ in thickness. These two types are known to vary in resistance to <em>Daphnia</em> <em>magna</em> grazing: thin filaments (&lt;2.5 µm) are more vulnerable to grazing than the thick ones (&gt;2.5 µm). In this study, we investigated whether the difference in the vulnerability to grazing of thin and thick filaments is a result of different thickness of their cell walls, a filament stiffness determinant. We expected thick filaments to have thicker cell walls than the thin ones. Additionally, we analysed whether cell wall thickness correlates with filament thickness regardless of the filament type. A morphometric analysis of cell walls was performed using transmission electron micrographs of ultra-thin sections of the batch-cultured cyanobacterial material.  Our study revealed that the thin type of filaments had thinner cell walls than the thick filaments. Moreover, cell wall thickness was positively correlated with filament thickness. TEM (transmission electron microscopy) observations also revealed that the thin type of filaments was often at different stages of autocatalytic cell destruction, which was mainly manifested in the increase in cell vacuolization and degradation of the cytoplasm content. Based on our findings, we assume that previously reported higher resistance of thick filaments to <em>Daphnia</em> grazing results from greater stiffness and excellent physiological conditions of thick filaments. </p>

Rotational Isomers in Anhydrides from IR Spectroscopy and MO Calculations

1985 ◽  
Vol 39 (6) ◽  
pp. 1030-1032 ◽  
Author(s):  
N. B. Colthup
Keyword(s):  
Ir Spectroscopy ◽  
Acetic Anhydride ◽  
Ab Initio ◽  
Linear Relationship ◽  
Liquid State ◽  
Intensity Ratio ◽  
Dihedral Angles ◽  
Mo Calculations ◽  
Rotational Isomers ◽  
Ab Initio Mo Calculations

In this study ab initio MO calculations were used to calculate the relative energies of various types of C-O rotational isomers in acetic anhydride. MO calculations were also used to predict the IR intensity ratio for the in-phase and out-of-phase carbonyl stretch bands in acetic anhydride. A linear relationship was developed between the intensity ratio and the square of the tangent of the C-O dihedral angles. This relationship was used to show that crystalline stearic anhydride has a planar skeleton and stearic anhydride in the liquid state has a C-O dihedral angle of about 32°.

Theory and Simulation of Dopant Diffusion in SiGe

2003 ◽  
Vol 765 ◽  
Author(s):  
Chun-Li Liu ◽  
Marius Orlowski ◽  
Aaron Thean ◽  
Alex Barr ◽  
Ted White ◽  
...  
Keyword(s):  
Volume Change ◽  
Defect Formation ◽  
Formation Enthalpy ◽  
Lattice Expansion ◽  
Strained Si ◽  
P Diffusion ◽  
Expansion Theory ◽  
The Difference ◽  
And Diffusion ◽  
Good Agreement

AbstractStrained Si-based technology has imposed a new challenge for understanding dopant implantation and diffusion in SiGe that is often used as the buffer layer for a strained Si cap layer. In this work, we describe our latest modeling effort investigating the difference in dopant implantation and diffusion between Si and SiGe. A lattice expansion theory was developed to account for the volume change due to Ge in Si and its effect on defect formation enthalpy. The theory predicts that As diffusion in SiGe is enhanced by a factor of ∼10, P diffusion by a factor of ∼2, and B diffusion is retarded by a factor of ∼6, when compared to bulk Si. These predictions are consistent with experiment. Dopant profiles for As, P, and B were simulated using process simulators FLOOPS and DIOS. The simulated profiles are in good agreement with experiment.

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