Effects of P-Coumarate 3-Hydroxylase Downregulation on the Compositional and Structural Characteristics of Lignin and Hemicelluloses in Poplar Wood (Populus alba × Populus glandulosa)

Elucidating the chemical and structural characteristics of hemicelluloses and lignin in the p-coumarate 3-hydroxylase (C3H) down-regulated poplar wood will be beneficial to the upstream gene validation and downstream biomass conversion of this kind of transgenic poplar. Herein, the representative hemicelluloses and lignin with unaltered structures were prepared from control (CK) and C3H down-regulated 84K poplars. Modern analytical techniques, such as 13C NMR, 2D-HSQC NMR, and gel chromatography (GPC), were performed to better delineate the structural changes of hemicelluloses and lignin caused by transgenesis. Results showed that both the hemicelluloses (H-CK and H-C3H) extracted from control and C3H down-regulated poplar wood have a chain backbone of (1→4)-β-D-Xylan with 4-O-Me-α-D-GlcpA as side chain, and the branch degree of the H-C3H is higher than that of H-CK. With regarding to the lignin macromolecules, NMR results demonstrated that the syringyl/guaiacyl (S/G) ratio and dominant substructure β-O-4 linkages in C3H down-regulated poplar were lower than those of control poplar wood. By contrast, native lignin from C3H down-regulated poplar wood exhibited higher contents of p-hydroxybenzoate (PB) and p-hydroxyphenyl (H) units. In short, C3H down-regulation resulted in the chemical and structural changes of the hemicelluloses and lignin in these poplar wood. The identified structures will facilitate the downstream utilization and applications of lignocellulosic materials in the biorefinery strategy. Furthermore, this study could provide some illuminating results for genetic breeding on the improvement of wood properties and efficient utilization of poplar wood.

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Structural Characteristics of the Guaiacyl-Rich Lignins From Rice (Oryza sativa L.) Husks and Straw

Frontiers in Plant Science ◽

10.3389/fpls.2021.640475 ◽

2021 ◽

Vol 12 ◽

Author(s):

Mario J. Rosado ◽

Jorge Rencoret ◽

Gisela Marques ◽

Ana Gutiérrez ◽

José C. del Río

Keyword(s):

Oryza Sativa ◽

Rice Straw ◽

Oryza Sativa L ◽

Structural Characteristics ◽

Analytical Techniques ◽

Gas Chromatography Mass Spectrometry ◽

Aryl Ether ◽

Rice Husks ◽

Alkyl Aryl ◽

G Ratio

Rice (Oryza sativa L.) is a major cereal crop used for human nutrition worldwide. Harvesting and processing of rice generates huge amounts of lignocellulosic by-products such as rice husks and straw, which present important lignin contents that can be used to produce chemicals and materials. In this work, the structural characteristics of the lignins from rice husks and straw have been studied in detail. For this, whole cell walls of rice husks and straw and their isolated lignin preparations were thoroughly analyzed by an array of analytical techniques, including pyrolysis coupled to gas chromatography-mass spectrometry (Py-GC/MS), nuclear magnetic resonance (NMR), and derivatization followed by reductive cleavage (DFRC). The analyses revealed that both lignins, particularly the lignin from rice husks, were highly enriched in guaiacyl (G) units, and depleted in p-hydroxyphenyl (H) and syringyl (S) units, with H:G:S compositions of 7:81:12 (for rice husks) and 5:71:24 (for rice straw). These compositions were reflected in the relative abundances of the different interunit linkages. Hence, the lignin from rice husks were depleted in β–O–4′ alkyl-aryl ether units (representing 65% of all inter-unit linkages), but presented important amounts of β–5′ (phenylcoumarans, 23%) and other condensed units. On the other hand, the lignin from rice straw presented higher levels of β–O–4′ alkyl-aryl ethers (78%) but lower levels of phenylcoumarans (β–5′, 12%) and other condensed linkages, consistent with a lignin with a slightly higher S/G ratio. In addition, both lignins were partially acylated at the γ-OH of the side-chain (ca. 10–12% acylation degree) with p-coumarates, which overwhelmingly occurred over S-units. Finally, important amounts of the flavone tricin were also found incorporated into these lignins, being particularly abundant in the lignin of rice straw.

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Overview of Popular Techniques of Raman Spectroscopy and Their Potential in the Study of Plant Tissues

Molecules ◽

10.3390/molecules26061537 ◽

2021 ◽

Vol 26 (6) ◽

pp. 1537

Author(s):

Aneta Saletnik ◽

Bogdan Saletnik ◽

Czesław Puchalski

Keyword(s):

Raman Spectroscopy ◽

Cell Walls ◽

Structural Changes ◽

Spatial Information ◽

Technological Development ◽

Analytical Techniques ◽

High Sensitivity ◽

Plant Tissues ◽

Wide Range ◽

Identification Technique

Raman spectroscopy is one of the main analytical techniques used in optical metrology. It is a vibration, marker-free technique that provides insight into the structure and composition of tissues and cells at the molecular level. Raman spectroscopy is an outstanding material identification technique. It provides spatial information of vibrations from complex biological samples which renders it a very accurate tool for the analysis of highly complex plant tissues. Raman spectra can be used as a fingerprint tool for a very wide range of compounds. Raman spectroscopy enables all the polymers that build the cell walls of plants to be tracked simultaneously; it facilitates the analysis of both the molecular composition and the molecular structure of cell walls. Due to its high sensitivity to even minute structural changes, this method is used for comparative tests. The introduction of new and improved Raman techniques by scientists as well as the constant technological development of the apparatus has resulted in an increased importance of Raman spectroscopy in the discovery and defining of tissues and the processes taking place in them.

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Study of Properties of Expanded Graphite – Polymer Porous Composite by Acoustic Emission Method

Archives of Metallurgy and Materials ◽

10.2478/amm-2013-0169 ◽

2013 ◽

Vol 58 (4) ◽

pp. 1331-1336 ◽

Cited By ~ 1

Author(s):

J. Berdowski ◽

S. Berdowska ◽

F. Aubry

Keyword(s):

Acoustic Emission ◽

Structural Changes ◽

Structural Characteristics ◽

Physical And Mechanical Properties ◽

Expanded Graphite ◽

Composite Membranes ◽

Acoustic Emission Method ◽

Emission Method ◽

Graphite Composite ◽

Wide Range

Abstract The purpose of this paper was to investigate the physical and mechanical properties of compressed expanded graphite (CEG) and their porous derivatives after impregnation, polymerization; and carbonization by the use of acoustic emission method (AE). The mechanical and structural characteristics of compressed expanded graphite and their three groups of porous composites after each technological process are presented and discussed. The measurements of acoustic emission parameters in these materials were carried out at wide range of frequency of the waves (0.1÷2.5 MHz). The changes of two of parameters: - AE pulses counts rate and spectrum distribution of AE waves - are presented in this paper. The analysis of the respective parameters AE also gives possibility to determine the micro- and macro structural changes of materials at different levels of technological processes. Applications of these materials as catalysts with high specific surface make them very interesting subject of study. Also compressed expanded graphite composite membranes prepared from furfuryl alcohol polymers are promising for gas separation.

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The structure and changes of China’s land system

China Agricultural Economic Review ◽

10.1108/caer-05-2018-0102 ◽

2019 ◽

Vol 11 (3) ◽

pp. 471-488 ◽

Cited By ~ 3

Author(s):

Liu Shouying

Keyword(s):

Economic Growth ◽

Institutional Change ◽

Structural Changes ◽

Structural Characteristics ◽

Institutional Arrangements ◽

Reform Process ◽

Content Type ◽

The Past ◽

Land System ◽

Rapid Economic Growth

Purpose The purpose of this paper is to analyze the structure and changes of China’s land system. To achieve this aim, the paper is divided into four parts. The first part gives a brief introduction to the structural characteristics of the Chinese land institutional arrangements; the second part analyzes the reform process of the land system in the past 40 years and its path of change; the third part engages the discussion about the historic contribution made by the land institutional change to rapid economic growth and structural changes; and the final part is conclusion and some policy implications. Design/methodology/approach After 40 years of reforms and opening up, China has not only created a growth miracle unparalleled for any major country in human history, but also transformed itself from a rural to an urban society. Behind this great transformation is a systemic reform in land institutions. Rural land institutions went from collectively owned to household responsibility system, thereby protecting farmers’ land rights. This process resulted in long-term sustainable growth in China’s agriculture, a massive rural-urban migration and a historical agricultural transformation. The conversion of agricultural land to non-agricultural uses and the introduction of market mechanisms made land a policy tool in driving high economic growth, industrialization and urbanization. Findings Research shows that the role of land and its relationship with the economy will inevitably change as China’s economy enters a new stage of medium-to-high speed growth. With economic restructuring, low-cost industrial land will be less effective. Urbanization is also shifting from rapid expansion to endogenous growth so that returns on land capitalization will decrease and risks will increase. Therefore, China must abandon land-dependent growth model through deepening land reforms and adapt a new pattern of economic development. Originality/value This paper gives a brief introduction to the structural characteristics of the Chinese land institutional arrangements, analyzes the reform process of the land system in the past 40 years and its path of change, and evaluates the historic contribution made by the land institutional change to rapid economic growth and structural changes.

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Methodology of a combined approach: analytical techniques to identify the technology and raw materials used in thin-walled pottery from Herculaneum and Pompeii

Analytical Methods ◽

10.1039/c3ay42195c ◽

2014 ◽

Vol 6 (10) ◽

pp. 3490-3499 ◽

Cited By ~ 11

Author(s):

L. C. Giannossa ◽

M. Acquaviva ◽

G. E. De Benedetto ◽

P. Acquafredda ◽

R. Laviano ◽

...

Keyword(s):

Raw Materials ◽

Structural Characteristics ◽

Analytical Techniques ◽

Combined Approach ◽

Thin Walled ◽

Materials Used

This study focuses on defining compositional and structural characteristics of ceramic bodies and surfaces of thin-walled pottery (2nd cent. BC–3rd cent. AD) in the Vesuvian area.

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Water Softening Mechanism and Strength Model for Saturated Carbonaceous Mudstone in Panzhihua Airport, China

Advances in Civil Engineering ◽

10.1155/2020/8874201 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Ziwen Wang ◽

Jifang Du ◽

Shuaifeng Wu ◽

Yingqi Wei ◽

Jianzhang Xiao ◽

...

Keyword(s):

Shear Strength ◽

Water Saturation ◽

Structural Characteristics ◽

Water Immersion ◽

Analytical Techniques ◽

Friction Angle ◽

Mechanical Tests ◽

Water Softening ◽

Softening Mechanism ◽

The Stability

To identify the water softening mechanisms that caused landslides in Panzhihua Airport, China, property and saturation tests of the mudstones extracted from a representative landslide were proposed. In this paper, water saturation tests were carried out on samples of carbonaceous mudstone collected from the east side of the No. 12 landslide at the airport. A number of different analytical techniques and mechanical tests were used to determine changes in chemical composition, mineral assemblages, and mudstone structural characteristics, including shear strength, after the mudstone had been softened. Three kinds of changes caused by water and three mudstone softening stages are proposed. The results show that the water has a significant influence on the properties of the mudstone, so the stability of the mudstone in the watery period is a big threat to the upper structure. A model for water immersion mudstone strength softening is developed. The model incorporates a permeability coefficient, the hydraulic gradient, and time; the model can be used to determine the mudstone’s shear strength and internal friction angle. This study provides a reference for the study of rock softened by water immersion.

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Investigation of the Structural Changes and Catalytic Properties of FeNi Nanostructures as a Result of Exposure to Gamma Radiation

Crystals ◽

10.3390/cryst10040254 ◽

2020 ◽

Vol 10 (4) ◽

pp. 254

Author(s):

Daryn B. Borgekov ◽

Maxim V. Zdorovets ◽

Dmitriy I. Shlimas ◽

Artem L. Kozlovskiy

Keyword(s):

Gamma Radiation ◽

Point Defects ◽

Gamma Rays ◽

Structural Changes ◽

Catalytic Properties ◽

Structural Characteristics ◽

Catalytic Reactions ◽

Radiation Doses ◽

Crystallite Orientation ◽

Complete Destruction

The paper presents the results of changes in the structural characteristics, and the degree of texturing of FeNi nanostructures close in composition to permalloy compounds as a result of directed modification by gamma radiation with an energy of 1.35 MeV and doses from 100 to 500 kGy. The choices of energy and radiation doses were due to the need to modify the structural properties, which consisted of annealing the point defects that occurred during the synthesis along the entire length of the nanotubes. The initial FeNi nanostructures were polycrystalline nanotubes of anisotropic crystallite orientation, obtained by electrochemical deposition. The study found that exposure to gamma rays led to fewer defects in the structure, and reorientation of crystallites, and at doses above 300 kGy, the presence of one selected texture direction (111) in the structure. During tests of the corrosion resistance of synthesized and modified nanostructures in a PBS solution at various temperatures, it was found that exposure to gamma rays led to a significant decrease in the rate of degradation of nanotubes and an increase in the potential life of up to 20 days. It was established that at the first stage of testing, the degradation of nanostructures is accompanied by the formation of oxide inclusions, which subsequently lead to the formation of pitting corrosion and subsequent partial or complete destruction of the nanostructures. It is shown that gamma radiation is promising not only for targeted modification of nanostructures and increasing resistance to degradation, but also for increasing the rate of catalytic reactions of the PNA-PPD type.

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Structural variations in strained crystalline multilayers

Journal of Materials Research ◽

10.1557/jmr.1994.2190 ◽

1994 ◽

Vol 9 (8) ◽

pp. 2190-2197 ◽

Cited By ~ 5

Author(s):

J. Hoekstra ◽

H. Yan ◽

G. Kalonji ◽

H. Jónsson

Keyword(s):

Structural Changes ◽

Elevated Temperatures ◽

Lattice Mismatch ◽

Structural Characteristics ◽

Binding Energies ◽

Structural Defects ◽

Interatomic Potentials ◽

Structural Variations ◽

Common Neighbor ◽

Hcp Structure

We present a computer simulation study of thin crystalline multilayers constructed from two fcc solids with differing lattice constants and binding energies. Initially the two solids have the same orientation, and the interface is perpendicular to the common [100] direction. We then minimize the energy of the system at zero temperature or equilibrate it at a finite temperature. Both materials are described by Lennard-Jones interatomic potentials. A novel technique for analyzing local atomic ordering, common neighbor analysis, is used to identify structural characteristics in these systems. As we gradually vary the lattice mismatch between the two solids, several structural changes are observed in the layers of smaller atoms after energy minimization. At a mismatch larger than 14%, the layers transform into the hep structure, while at smaller mismatches extended structural defects are generated. At elevated temperatures, the hcp structure is transformed back to fcc, and the structure defects disappear.

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Invited Commentary: Biomarkers for Mortality Among Individuals With a History of Out-of-Home Care—Implications for Study Design and Conceptualizations of Risk

American Journal of Epidemiology ◽

10.1093/aje/kwaa077 ◽

2020 ◽

Vol 190 (1) ◽

pp. 179-182

Author(s):

Hilary K Brown

Keyword(s):

Home Care ◽

Prolonged Exposure ◽

Analytical Techniques ◽

Childhood And Adolescence ◽

Out Of Home Care ◽

Markers Of Inflammation ◽

Health Related ◽

Risk Approach ◽

History Of ◽

A Chain

Abstract Out-of-home care in childhood and adolescence has been shown to be associated with elevated risk for all-cause mortality in adulthood, with adverse socioeconomic, psychosocial, and health-related trajectories hypothesized to mediate this relationship. In the research letter by Batty and Hamer (Am J Epidemiol. 2021;190(1):176–178), the authors used data from the 1970 British birth cohort (n = 8,581) to examine risk of biomarkers for mortality in adults with a history of out-of-home care. While markers of inflammation, glucose metabolism, and lipids were less favorable in the exposed versus unexposed, differences between groups were small and were completely attenuated after adjustment. This study raises important issues regarding the design and conceptualization of future studies on the long-term outcomes of out-of-home care recipients. Such studies require more detailed information on duration of care, type of care setting, and reasons for care, all of which could affect outcome risk. Because the duration of follow-up is long, and attrition likely, authors should consider use of novel analytical techniques to account for selection bias, such as inverse probability weighting. Finally, a “chain-of-risk” approach to understanding outcomes might be warranted, given that risk is likely explained by accumulation of and prolonged exposure to adverse socioeconomic, psychosocial, and health risks.

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Effects of Different Working Modes of Ultrasound on Structural Characteristics of Zein and ACE Inhibitory Activity of Hydrolysates

Journal of Food Quality ◽

10.1155/2017/7896037 ◽

2017 ◽

Vol 2017 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Xiaofeng Ren ◽

Xi Zhang ◽

Qiufang Liang ◽

Ting Hou ◽

Huiji Zhou

Keyword(s):

Inhibitory Activity ◽

Fluorescence Spectra ◽

Structural Changes ◽

Structural Characteristics ◽

Intrinsic Fluorescence ◽

Cd Spectra ◽

Fixed Frequency ◽

Ace Inhibitory Activity ◽

Ace Inhibitory ◽

Frequency Ultrasound

Ultrasound was used as a new technology to pretreat protein prior to proteolysis to improve enzymolysis efficiency. The effects of different working modes of ultrasound on the angiotensin I-converting enzyme (ACE) inhibitory activity of zein hydrolysates and the structural characteristics of zein were investigated. The solubility, surface hydrophobicity (H0), ultraviolet-visible (UV-Vis) spectra, intrinsic fluorescence spectra, and circular dichroism (CD) spectra of zein pretreated with ultrasound were determined. All ultrasound pretreatments significantly improved the ACE inhibitory activity of zein hydrolysates (p<0.05). The highest ACE inhibitory activity, representing an increase of 99.21% over the control, was obtained with dual sweeping frequency ultrasound of 33±2 and 68±2 kHz. The effects of single sweeping frequency and dual fixed frequency ultrasound were stronger than those of single fixed frequency ultrasound for improving the ACE inhibitory activity of zein. Structural changes in zein were induced by ultrasound, as confirmed by changes in the solubility, H0, UV-Vis spectra, intrinsic fluorescence spectra, and CD spectra of zein, and these were consistent with the corresponding ACE inhibitory activities of zein hydrolysates. Thus, ultrasound working mode and frequency have significant effects on the structure of zein and the ACE inhibitory activity of zein hydrolysates.

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