Nanostructural assembly of cellulose, hemicellulose, and lignin in the middle layer of secondary wall of ginkgo tracheid

2009 ◽  
Vol 55 (6) ◽  
pp. 409-416 ◽  
Author(s):  
Noritsugu Terashima ◽  
Kohei Kitano ◽  
Miho Kojima ◽  
Masato Yoshida ◽  
Hiroyuki Yamamoto ◽  
...  
Keyword(s):  
Secondary Wall ◽  
Middle Layer

Review — The Orientation of Cellulose Microfibrils in the cell walls of Tracheids in Conifers

IAWA Journal ◽  
2005 ◽  
Vol 26 (2) ◽  
pp. 161-174 ◽  
Author(s):  
Hisashi Abe ◽  
Ryo Funada
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Outer Layer ◽  
Cell Walls ◽  
Secondary Wall ◽  
Middle Layer ◽  
Cellulose Microfibrils ◽  
Conifer Species ◽  
Predominant Orientation ◽  
Scanning Electron

We examined the orientation of cellulose microfibrils (Mfs) in the cell walls of tracheids in some conifer species by field emission-scanning electron microscopy (FE-SEM) and developed a model on the basis of our observations. Mfs depositing on the primary walls in differentiating tracheids were not well-ordered. The predominant orientation of the Mfs changed from longitudinal to transverse, as the differentiation of tracheids proceeded. The first Mfs to be deposited in the outer layer of the secondary wall (S1 layer) were arranged as an S-helix. Then the orientation of Mfs changed gradually, with rotation in the clockwise direction as viewed from the lumen side of tracheids, from the outermost to the innermost S1 layer. Mfs in the middle layer of the secondary wall (S2 layer) were oriented in a steep Z-helix with a deviation of less than 15° within the layer. The orientation of Mfs in the inner layer of the secondary wall (S3 layer) changed, with rotation in a counterclockwise direction as viewed from the lumen side, from the outermost to the innermost S3 layer. The angle of orientation of Mfs that were deposited on the innermost S3 layer varied among tracheids from 40° in a Z-helix to 20° in an S-helix.

The opening and shedding mechanism of the female cones of Pinus radiata

1964 ◽  
Vol 12 (2) ◽  
pp. 125 ◽  
Author(s):  
R Allen ◽  
AB Wardrop
Keyword(s):  
Pinus Radiata ◽  
Radial Growth ◽  
Secondary Wall ◽  
Vascular Tissue ◽  
Middle Layer ◽  
Cell Axis ◽  
Vascular Connection ◽  
Differential Shrinkage ◽  
Longitudinal Cell ◽  
Cone Scale

The opening of the female cones of P. radiata has been shown to result from differential shrinkage between the adaxial vascular tissue and the abaxial sclerenchyma of the cone scale. The organization of the secondary wall of the tracheids typically consists of three helically organized concentric layers. In the outer and inner layers the microfibrillar orientation is approximately transverse, and in the middle layer the helix makes an angle of c. 40° with the longitudinal cell axis. In the sclerenchyma the secondary wall consists of wide layers in which the microfibrils of the lamellae are almost transverse to the longitudinal cell axis, alternating with narrow layers in which the microfibrils of the lamellae are almost parallel to the cell axis. Opening is preceded by a severance of the vascular connection between the cone and the stem or branch by the occlusion of the lurnina of the tracheids of the peduncle with resin. As radial growth of the stem proceeds, small fissures develop between the xylem of the stem or branch and that of the cone peduncle. The fissures become filled with resin and there is a progressive erosion of the tracheids of the peduncle until ultimately the xylem of the peduncle is separated from that of the stem or branch.

Molecular mechanism of AtGA3OX1 and AtGA3OX2 genes affecting secondary wall thickening in stems in Arabidopsis

2013 ◽  
Vol 35 (5) ◽  
pp. 655-665 ◽  
Author(s):  
Zeng-Guang WANG ◽  
Guo-Hua CHAI ◽  
Zhi-Yao WANG ◽  
Xian-Feng TANG ◽  
Chang-Jiang SUN ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Secondary Wall ◽  
Wall Thickening ◽  
Secondary Wall Thickening

Effect of CeO2 Modified MAS Middle Layer on the Joint of C/C-LAS

2013 ◽  
Vol 28 (12) ◽  
pp. 1345-1348
Author(s):  
Huan-Xia ZHU ◽  
Ke-Zhi LI ◽  
Jin-Hua LU ◽  
He-Jun LI ◽  
Jian-Yang WANG
Keyword(s):  
Middle Layer

Improved Environment-Aware–Based Noise Reduction System for Cochlear Implant Users Based on Knowledge Transfer Approach (Preprint)

2020 ◽  
Author(s):  
Lieber Po-Hung Li ◽  
Ji-Yan Han ◽  
Wei-Zhong Zheng ◽  
Ren-Jie Huang ◽  
Ying-Hui Lai
Keyword(s):  
Knowledge Transfer ◽  
Cochlear Implant ◽  
Noise Reduction ◽  
Speech Intelligibility ◽  
Middle Layer ◽  
Successful Implementation ◽  
Perceptual Evaluation ◽  
Reduction System ◽  
Listening Tests ◽  
Implementation Costs

BACKGROUND The cochlear implant technology is a well-known approach to help deaf patients hear speech again. It can improve speech intelligibility in quiet conditions; however, it still has room for improvement in noisy conditions. More recently, it has been proven that deep learning–based noise reduction (NR), such as noise classification and deep denoising autoencoder (NC+DDAE), can benefit the intelligibility performance of patients with cochlear implants compared to classical noise reduction algorithms. OBJECTIVE Following the successful implementation of the NC+DDAE model in our previous study, this study aimed to (1) propose an advanced noise reduction system using knowledge transfer technology, called NC+DDAE_T, (2) examine the proposed NC+DDAE_T noise reduction system using objective evaluations and subjective listening tests, and (3) investigate which layer substitution of the knowledge transfer technology in the NC+DDAE_T noise reduction system provides the best outcome. METHODS The knowledge transfer technology was adopted to reduce the number of parameters of the NC+DDAE_T compared with the NC+DDAE. We investigated which layer should be substituted using short-time objective intelligibility (STOI) and perceptual evaluation of speech quality (PESQ) scores, as well as t-distributed stochastic neighbor embedding to visualize the features in each model layer. Moreover, we enrolled ten cochlear implant users for listening tests to evaluate the benefits of the newly developed NC+DDAE_T. RESULTS The experimental results showed that substituting the middle layer (ie, the second layer in this study) of the noise-independent DDAE (NI-DDAE) model achieved the best performance gain regarding STOI and PESQ scores. Therefore, the parameters of layer three in the NI-DDAE were chosen to be replaced, thereby establishing the NC+DDAE_T. Both objective and listening test results showed that the proposed NC+DDAE_T noise reduction system achieved similar performances compared with the previous NC+DDAE in several noisy test conditions. However, the proposed NC+DDAE_T only needs a quarter of the number of parameters compared to the NC+DDAE. CONCLUSIONS This study demonstrated that knowledge transfer technology can help to reduce the number of parameters in an NC+DDAE while keeping similar performance rates. This suggests that the proposed NC+DDAE_T model may reduce the implementation costs of this noise reduction system and provide more benefits for cochlear implant users.

SIMULATION OF MIDDLE LAYER TURBIDITY PEAK AND BLUE TIDE

2019 ◽  
Vol 75 (2) ◽  
pp. I_997-I_1002
Author(s):  
Teruhisa OKADA ◽  
Masahiro IMAMURA
Keyword(s):  
Middle Layer

scholarly journals MYB Transcription Factors and Its Regulation in Secondary Cell Wall Formation and Lignin Biosynthesis during Xylem Development

2021 ◽  
Vol 22 (7) ◽  
pp. 3560
Author(s):  
Ruixue Xiao ◽  
Chong Zhang ◽  
Xiaorui Guo ◽  
Hui Li ◽  
Hai Lu
Keyword(s):  
Cell Wall ◽  
Transcription Factors ◽  
Secondary Wall ◽  
Secondary Cell Wall ◽  
Lignin Biosynthesis ◽  
Cell Wall Formation ◽  
Long Distance ◽  
Secondary Cell Wall Formation ◽  
Myb Transcription Factors ◽  
Wall Formation

The secondary wall is the main part of wood and is composed of cellulose, xylan, lignin, and small amounts of structural proteins and enzymes. Lignin molecules can interact directly or indirectly with cellulose, xylan and other polysaccharide molecules in the cell wall, increasing the mechanical strength and hydrophobicity of plant cells and tissues and facilitating the long-distance transportation of water in plants. MYBs (v-myb avian myeloblastosis viral oncogene homolog) belong to one of the largest superfamilies of transcription factors, the members of which regulate secondary cell-wall formation by promoting/inhibiting the biosynthesis of lignin, cellulose, and xylan. Among them, MYB46 and MYB83, which comprise the second layer of the main switch of secondary cell-wall biosynthesis, coordinate upstream and downstream secondary wall synthesis-related transcription factors. In addition, MYB transcription factors other than MYB46/83, as well as noncoding RNAs, hormones, and other factors, interact with one another to regulate the biosynthesis of the secondary wall. Here, we discuss the biosynthesis of secondary wall, classification and functions of MYB transcription factors and their regulation of lignin polymerization and secondary cell-wall formation during wood formation.

scholarly journals WALL STRESS IN ASCENDING AORTA ANEURYSMS AS A PREDICTIVE FACTOR OF BREAKAGE

2021 ◽  
Vol 108 (Supplement_3) ◽  
Author(s):  
R J Burgos Lázaro ◽  
N Burgos Frías ◽  
S Serrano-Fiz García ◽  
V Ospina Mosquera ◽  
F Rojo Pérez ◽  
...  
Keyword(s):  
Aortic Wall ◽  
Wall Stress ◽  
Middle Layer ◽  
Ascending Aorta ◽  
Aortic Aneurysms ◽  
Maximum Diameter ◽  
Resistance Factors ◽  
Risk Of Rupture ◽  
Traction Test

Abstract INTRODUCTION The surgical indication for ascending aortic aneurysms (AAA) is established when the maximum diameter > 50 mm; It responds to Laplace's Law (T wall = P × r / 2e). The aim of the study is to define wall stress in AAA. MATERIAL AND METHODS 218 ascending aortic walls have been studied: 96 from organ donors, and 122 from AAA: Marfán 58 (47.5%), bicuspid aortic valve 26 (21.4%), and atherosclerosis 38 (31.1%). The samples were studied "in vitro", according to the model Young's (relationship between stress and deformed area), by means of the mechanical traction test (Tension = Force / Area). The analysis was performed with the stress-elongation curve (d Tension / d Elongation). RESULTS The stress of the aortic wall, classified from highest to lowest according to pathology and age was: cystic necrosis of the middle layer, arteriosclerosis, age > 60 years, between 35 and 59, and < 34 years. The stress of “control aortas” wall increased directly in relation to the age of the donors. CONCLUSIONS The maximum diameter of the ascending aorta, the patient's type of pathology and age are factors that affect the maximum tension of the aortic wall and resistance, factors that allow differentiation and prediction of the risk of rupture of the AAA. The validation of the results obtained through numerical simulation was significant and the uniaxial analysis has modeled the response of the vessels to their internal pressure.

Sign in / Sign up

Export Citation Format

Share Document