Topochemical investigation on phenolic deposits in the vessels of afzelia (Afzelia spp.) and merbau (Intsia spp.) heartwood

Holzforschung ◽  
2006 ◽  
Vol 60 (6) ◽  
pp. 583-588 ◽  
Author(s):  
Gerald Koch ◽  
Hans-Georg Richter ◽  
Uwe Schmitt
Keyword(s):  
Chemical Composition ◽  
Uv Absorbance ◽  
Pit Membrane ◽  
Parenchyma Cells ◽  
Vessel Walls ◽  
Distinct Maximum ◽  
Uv Microspectrophotometry ◽  
Absorbance Spectra

Abstract The topochemical distribution of phenolic deposits in the vessels of afzelia (Afzelia spp.) and merbau (Intsia spp.) heartwood was investigated by means of cellular UV microspectrophotometry (UMSP) to characterise the chemical composition and synthesis by pit membrane-associated enzymes. UV absorbance spectra of the deposits attached to the vessel walls of merbau are characterised by a distinct maximum at a wavelength of 368 nm representing the UV absorbance of pure robinetin (C15H10O7). Deposits in the vessels of afzelia display a typical spectrum of kaempferol (C15H10O2) with two distinct maxima at 270 and 350 nm. The pit membranes and pit canals of associated vessel and parenchyma cells are impregnated by these compounds. These results verify the assumption that the synthesis of deposits in afzelia and merbau is regulated by pit membrane-associated enzymes.

scholarly journals Anatomy, Cell Wall Structure and Topochemistry of Water-Logged Archaeological wood aged 5,200 and 4,500 years

IAWA Journal ◽  
2008 ◽  
Vol 29 (1) ◽  
pp. 55-68 ◽  
Author(s):  
Katarina Čufar ◽  
Jožica Gričar ◽  
Martin Zupančič ◽  
Gerald Koch ◽  
Uwe Schmitt
Keyword(s):  
Cell Types ◽  
Wall Structure ◽  
Normal Wood ◽  
Uv Absorbance ◽  
Archaeological Wood ◽  
Transmission Electron ◽  
Parenchyma Cells ◽  
Prehistoric Settlements ◽  
And Storage ◽  
Uv Microspectrophotometry

Evaluating the state of deterioration of water-logged archaeological wood is necessary in order to select treatments for its conservation and storage, particularly in the case of valuable archaeological artefacts. For this purpose archaeological wood of ash (Fraxinus sp.) and oak (Quercus sp.) buried in water-logged conditions at prehistoric settlements on the Ljubljansko barje (Ljubljana moor), Slovenia, aged approx. 5,200 and 4,500 years, was investigated by means of light microscopy (LM), transmission electron microscopy (TEM) and cellular UV-microspectrophotometry (UMSP). LM and TEM revealed that the ash wood aged 5,200 years was the least preserved. The secondary walls of fibres, vessels and parenchyma cells were considerably thinner than in normal wood, indicating distinct degradation. TEM and UMSP additionally revealed strong delignification of the remaining parts of the secondary walls of all cell types. The compound middle lamellae appeared structurally intact, but had lower UV-absorbance than normal wood of the same species. The cell corners were topochemically unchanged, as shown by high analogue UV-absorbance. The UV-absorbance maxima at a wavelength of 278 nm corresponded to those of hardwood lignins. The oak heartwood was generally better preserved than the ash wood. Within each species, the 4,500- year-old samples generally appeared better preserved than those 5,200 years old.

Topochemical Characterisation of Phenolic Extractives in Discoloured Beechwood (Fagus sylvatica L.)

Holzforschung ◽  
2003 ◽  
Vol 57 (4) ◽  
pp. 339-345 ◽  
Author(s):  
G. Koch ◽  
J. Puls ◽  
J. Bauch
Keyword(s):  
High Performance ◽  
Cellular Level ◽  
Uv Absorbance ◽  
Methanol Extracts ◽  
Absorbance Maximum ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Fagus Sylvatica L ◽  
Ray Parenchyma Cells ◽  
Uv Microspectrophotometry

Summary The topochemical distribution of phenolic extractives in steamed and kiln-dried beechwood with discolourations was investigated on a cellular level by using scanning UV microspectrophotometry (UMSP). For the chemical characterisation of accessory compounds, acetone and methanol extracts of the discoloured beechwood were separated by accelerated solvent extraction (ASE) and analysed with high performance liquid chromatography (HPLC). The UV microscopic investigations reveal that the accessory compounds responsible for the discolouration of beechwood are mainly restricted to the longitudinal and ray parenchyma cells and the lumen of vessels. The detected extractives are characterised by high UV absorbance values and an absorbance maximum in a wavelength range between 280 and 290 nm. The separation of the acetone and methanol extracts of discoloured beechwood shows the presence of different low molecular phenols such as catechin and 2,6-dimethoxybenzochinon, which are transformed into high condensation compounds during steaming and kiln-drying.

Quantitative UV Absorbance Spectra of Chemical Agents and Simulants

2008 ◽  
Author(s):  
J. M. Lochner ◽  
Aaron M. Hyre ◽  
Steven D. Christesen ◽  
Kristina R. Gonser
Keyword(s):  
Uv Absorbance ◽  
Chemical Agents ◽  
Absorbance Spectra

Anatomy and Chemical Composition of Pinus Pinaster Bark

IAWA Journal ◽  
1996 ◽  
Vol 17 (2) ◽  
pp. 141-150 ◽  
Author(s):  
Elsa Nunes ◽  
Teresa Quilhó ◽  
Helena Pereira
Keyword(s):  
Chemical Composition ◽  
Pinus Pinaster ◽  
Variable Number ◽  
Starch Granules ◽  
Secondary Phloem ◽  
Scale Type ◽  
Resin Ducts ◽  
Sieve Cells ◽  
Parenchyma Cells

The secondary phloem of Pinus pinaster Aiton bark has sieve cells and axial and radial parenchyma, but no fibres. Resin ducts are present in fusiform rays . Stiloid crystals, starch granules and tannins occur inside sieve and parenchyma cells. The rhytidome of P. pinaster bark has a variable number of periderms forming scale-type discontinuous layers over expanded parenchyma cells. Phellem comprises 4-6 layers of thickwaIled and little suberized cells and phelloderm a layer of 2 or 3 thickened lignified ceIls and a layer of expanded cells.

scholarly journals Optical Method for Cardiovascular Risk Marker Uric Acid Removal Assessment during Dialysis

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jana Holmar ◽  
Ivo Fridolin ◽  
Fredrik Uhlin ◽  
Kai Lauri ◽  
Merike Luman
Keyword(s):  
Uric Acid ◽  
Uv Absorbance ◽  
Chemical Laboratory ◽  
Dialysis Treatment ◽  
Mean Values ◽  
Double Beam ◽  
Multi Wavelength ◽  
Spent Dialysate ◽  
Treatment Procedures ◽  
Absorbance Spectra

The aim of this study was to estimate the concentration of uric acid (UA) optically by using the original and processed ultraviolet (UV) absorbance spectra of spent dialysate. Also, the effect of using several wavelengths (multi-wavelength algorithms) for estimation was examined. This paper gives an overview of seven studies carried out in Linköping, Sweden, and Tallinn, Estonia. A total of 60 patients were monitored over their 188 dialysis treatment procedures. Dialysate samples were taken and analysed by means of UA concentration in a chemical laboratory and with a double-beam spectrophotometer. The measured UV absorbance spectra were processed. Three models for the original and three for the first derivate of UV absorbance were created; concentrations of UA from the different methods were finally compared in terms of mean values and SD. The mean concentration (micromol/L) of UA was49.7±23.0measured in the chemical laboratory, and48.9±22.4calculated with the best estimate among all models. The concentrations were not significantly different (P≥0.17). It was found that using a multi-wavelength and processed signal approach leads to more accurate results, and therefore these approaches should be used in future.

The fine structure of the pits of Eucalyptus regnans (F. Muell.) and their relation to the movement of liquids into the wood

1960 ◽  
Vol 8 (1) ◽  
pp. 51 ◽  
Author(s):  
J Cronshaw
Keyword(s):  
Secondary Wall ◽  
Structural Features ◽  
Cellulose Microfibrils ◽  
Primary Wall ◽  
Detailed Structure ◽  
Eucalyptus Regnans ◽  
Pit Membrane ◽  
Parenchyma Cells ◽  
Ray Parenchyma ◽  
Ray Parenchyma Cells

Observstion in the electron microscope of carbon replicas of the pits of vessels, ray parenchyma cells, fibres, and tracheids of Eucalyptus regnans has shown the detailed structure of the pit borders and the pit closing membranes. In all cases in the mature wood the primary wall is left apparently without modification as the pit membrane. Unlike the borders of the pits of fibre tracheids and tracheids, the pit borders of the vessels are not separate; the cellulose microfibrils of a border may be common to several pits. The pit borders of fibre traoheids and tracheids are developed as separate entities and have a structure similar to the pit borders of softwood tracheids. The structure of the secondary wall layers associated with the pits is described and related to the structure of the pits. The fine structural features of the pits, especially of the pit closing membranes, are discussed in relation to the movement of liquids into wood.

The Protective Layer as an Extension of the Apoplast

IAWA Journal ◽  
1993 ◽  
Vol 14 (2) ◽  
pp. 163-171 ◽  
Author(s):  
J. R. Barnett ◽  
P. Cooper ◽  
Lynda J. Bonner
Keyword(s):  
Cell Wall ◽  
Protective Layer ◽  
Xylem Parenchyma ◽  
Pit Membrane ◽  
Parenchyma Cells ◽  
Deep Supercooling ◽  
Dying Cells ◽  
Tylose Formation ◽  
Universal Application

The protective layer between the cell wall and plasmalemma of xylem parenchyma cells has variously been suggested to be involved in protection of the protoplast from attack by autolytic enzymes from neighbouring, dying cells, tylose formation, deep supercooling of xylem, and strengthening of the pit. None of these ideas has universal application to all species in which parenchyma cells possess a protective layer. It is proposed instead, that the protective layer is primarily laid down in order to preserve apoplastic continuity around the protoplast of a lignified cell, bringing the entire plasmalemma surface, and not just that part of it in contact with the porous pit membrane, into contact with the apoplast. If this is so, then other functions may be coincidental, or have arisen secondarily.

scholarly journals Comparison of colors, microstructure, chemical composition and thermal properties of bamboo fibers and parenchyma cells with heat treatment

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Jieyu Wu ◽  
Tuhua Zhong ◽  
Wenfu Zhang ◽  
Jiangjing Shi ◽  
Benhua Fei ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Properties ◽  
Chemical Composition ◽  
Lignin Content ◽  
Treatment Temperature ◽  
Composition Analysis ◽  
Chemical Compositions ◽  
Cellulose Content ◽  
Parenchyma Cells ◽  
Bamboo Fibers

AbstractThe effects of heat treatment at various temperatures on mechanically separated bamboo fibers and parenchyma cells were examined in terms of color, microstructure, chemical composition, crystallinity, and thermal properties. The heat-treated parenchyma cells and fibers were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), chemical composition analysis, and thermogravimetric analysis (TGA). The results revealed that the colors of bamboo fibers and parenchyma cells were darkened as treatment temperature increased. The microstructure of the treated fibers and parenchyma cells slightly changed, yet the shape of starch granules in parenchyma cells markedly altered at a temperature of above 160 °C. The chemical compositions varied depending on the heat treatment temperature. When treated at 220 °C, the cellulose content was almost unchanged in fibers but increased by 15% in parenchyma cells; the hemicellulose content decreased and the lignin content increased regardless of fibers and parenchyma cells. The cellulose crystal structure was nearly unaffected by heat treatment, but the cellulose crystallinity of fibers changed more pronouncedly than that of parenchyma cells. The thermal stability of parenchyma cells after heat treatment was affected more substantially compared to fibers.

Understanding the behaviour of UV absorbance of natural waters upon chlorination using model compounds

2019 ◽  
Vol 5 (1) ◽  
pp. 172-184 ◽  
Author(s):  
Nicolas Beauchamp ◽  
Caetano Dorea ◽  
Christine Beaulieu ◽  
Christian Bouchard ◽  
Manuel Rodriguez
Keyword(s):  
Natural Waters ◽  
Uv Absorbance ◽  
Model Compounds ◽  
Chemical Structures ◽  
Uv Visible ◽  
By Products ◽  
Absorbance Spectra

This paper is the first to assess the chemical structures responsible for specific changes observed in the shape of the UV-visible absorbance spectra, and their relationship to disinfection by-products.

Predicting the UV Spectrum of Single Stranded DNA

2015 ◽  
Vol 804 ◽  
pp. 163-166
Author(s):  
Naphat Chathirat
Keyword(s):  
Experimental Result ◽  
Uv Absorbance ◽  
Uv Spectrum ◽  
Single Stranded Dna ◽  
Absorbance Spectra

A model was developed to predict the UV absorbance spectra and thus concentration of single stranded DNA (ssDNA) samples. The model was developed from UV absorbance spectra of ssDNA oligodeoxynucleotides determined at different concentrations. The model, which would predict the concentration of ssDNA from the A260 value, is shown to predict absorbance spectra of ssDNA as shown when compared to the experimental result.

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