scholarly journals RESPONSE TO BORON DEFICIENCY: A COMPARISON WITH RESPONSES PRODUCED BY CHEMICAL METHODS OF RETARDING ROOT ELONGATION

1974 ◽  
Vol 73 (5) ◽  
pp. 821-832 ◽  
Author(s):  
G. A. ROBERTSON ◽  
B. C. LOUGHMAN
Keyword(s):  
Root Elongation ◽  
Boron Deficiency ◽  
Chemical Methods

Ultrastructural changes in sunflower root cells in relation to boron deficiency and added auxin

1980 ◽  
Vol 58 (8) ◽  
pp. 856-866 ◽  
Author(s):  
Ann M. Hirsch ◽  
John G. Torrey
Keyword(s):  
Cell Expansion ◽  
Root Elongation ◽  
Membrane Integrity ◽  
Ultrastructural Level ◽  
Ultrastructural Changes ◽  
Boron Deficiency ◽  
Endogenous Auxin ◽  
Root Cells ◽  
Seedling Roots ◽  
Inhibition Of Root Elongation

The responses of sunflower root cells to conditions of boron deficiency and to the addition of exogenous auxin were studied on the ultrastructural level. Although gross morphological effects such as inhibition of root elongation and a change in the direction of cell expansion from longitudinal to radial are similar in both auxin-treated and boron-deficient seedling roots, ultrastructural changes are different in the two treatments. An increase in cell wall thickness and a loss of membrane integrity are seen as early as 6 h in seedlings grown without boron. Auxin-treated root cells do not show this response. A role for boron may involve maintenance of membrane integrity rather than determining endogenous auxin levels.

scholarly journals Boron deficiency-induced root growth inhibition is mediated by brassinosteroid signalling regulation in Arabidopsis

2019 ◽  
Author(s):  
Cheng Zhang ◽  
Mingliang He ◽  
Sheliang Wang ◽  
Liuyang Chu ◽  
Chuang Wang ◽  
...  
Keyword(s):  
Root Growth ◽  
Growth Inhibition ◽  
Root Elongation ◽  
Mrna Level ◽  
Root Growth Inhibition ◽  
Boron Deficiency ◽  
Sequencing Analysis ◽  
Nuclear Signal ◽  
Condition B

ABSTRACTBrassinosteroid (BR) is a pivotal phytohormone involved in regulating root development. Boron (B) is an essential micronutrient for plant growth and development, and root growth of plants is rapidly inhibited under B deficiency condition, but the mechanisms are still elusive. Here, we demonstrate that BR plays crucial roles in these processes. We identify BR-related processes underlying B deficiency at the physiological, genetic, molecular/cell biological and transcriptome levels, and provide strong evidences that B deficiency can affect BR signalling, thereby altering root growth. RNA-sequencing analysis reveals a high co-regulation between BR-regulated genes and B deficiency-responsive genes. We found that low B negatively regulates BR signalling to control BR signalling-dependent root elongation, bes1-D exhibits insensitivity to low B stress, and bri1-301 mutants fails to respond to B depletion. Exogenous eBL application can rescue the inhibition of root growth under B deficiency condition, and application of BR biosynthesis inhibitor BRZ aggravates root growth inhibition of wild-type under B deficiency condition. B deficiency reduces the nuclear signal of BES1. We further found that B deficiency reduces the accumulation of brassinolide (BL) by reducing BR6ox1 and BR6ox2 mRNA level to down-regulate BR signalling and modulate root elongation. Altogether, our results uncover a role of BR signalling in root elongation under B deficiency.One-sentence summaryB deficiency reduces the accumulation of brassinolide by reducing BR6ox1 and BR6ox2 mRNA level to down-regulate BR signalling and modulate root elongation.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Sem and X-Ray Analysis of Renal and Biliary Calculi

1976 ◽  
Vol 34 ◽  
pp. 306-307
Author(s):  
R. J. Narconis ◽  
G. L. Johnson
Keyword(s):  
Chemical Constituents ◽  
Natural State ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Additional Dimension ◽  
Biliary Calculi ◽  
Calculus Formation ◽  
Scanning Electron

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.

A Plug-and-Play Approach for the De Novo Generation of Dually Functionalised Bispecifics

2019 ◽  
Author(s):  
Antoine Maruani ◽  
Peter A. Szijj ◽  
Calise Bahou ◽  
João C. F. Nogueira ◽  
Stephen Caddick ◽  
...  
Keyword(s):  
De Novo ◽  
Therapeutic Index ◽  
Antibody Fragments ◽  
Bispecific Antibodies ◽  
Full Potential ◽  
Mechanisms Of Resistance ◽  
Large Excess ◽  
Chemical Methods ◽  
New Class ◽  
Novel Approach

<p>Diseases are multifactorial, with redundancies and synergies between various pathways. However, most of the antibody-based therapeutics in clinical trials and on the market interact with only one target thus limiting their efficacy. The targeting of multiple epitopes could improve the therapeutic index of treatment and counteract mechanisms of resistance. To this effect, a new class of therapeutics emerged: bispecific antibodies.</p><p>Bispecific formation using chemical methods is rare and low yielding and/or requires a large excess of one of the two proteins to avoid homodimerisation. In order for chemically prepared bispecifics to deliver their full potential, high-yielding, modular and reliable cross-linking technologies are required. Herein, we describe a novel approach not only for the rapid and high-yielding chemical generation of bispecific antibodies from native antibody fragments, but also for the site-specific dual functionalisation of the resulting bioconjugates. Based on orthogonal clickable functional groups, this strategy enables the assembly of functionalised bispecifics with controlled loading in a modular and convergent manner.</p>

Studies on Chemical Methods to Expose Gate/Tunnel Oxide and Identification of Gate/Tunnel Oxide Defects in Wafer Fabrication

2002 ◽  
Author(s):  
Y. N. Hua ◽  
G. B. Ang ◽  
S. Redkar ◽  
Yogaspari ◽  
Wilma Richter
Keyword(s):  
Acetic Acid ◽  
Silicon Oxide ◽  
Wafer Fabrication ◽  
Chemical Methods ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Capacitor Structure ◽  
Oxide Defects ◽  
Buffer Oxide Etchant ◽  
Etch Time

Abstract In failure analysis of wafer fabrication, currently, three different types of chemical methods including 6:6:1 (Acetic Acid/HNO3/HF), NaOH and Choline are used in removing polysilicon (poly) layer and exposing the gate/tunnel oxide underneath. However, usage is limited due to their disadvantages. For example, 6:6:1 is a relatively fast etchant, but it is difficult to control the etch time and keep the oxide layer intact. Also, while using NaOH to remove poly and expose the silicon oxide, the solution needs to be heated. It is also difficult to etch a poly layer with a WSix or a CoSix silicide using NaOH. In this paper, we will discuss these 3 etchants in terms of their advantages and disadvantages. We will then introduce a new poly etchant, called HB91. HB91 is useful for removing poly to expose the gate/tunnel oxide for identification of related defects. HB91 is actually a mixture of two chemicals namely nitric acid (HNO3) and buffer oxide etchant (BOE) in a 9:1 ratio. The experimental results show that it is highly selective in poly removal with respect to the gate/tunnel oxide and is a suitable poly etchant especially for removing polysilicon with/without WSix and CoSix in the large capacitor structure. Application results of this poly etchant (HB91) will be presented.

Precision Xe Plasma FIB Delayering for Physical Failure Analysis of Sub-20 nm Microprocessor Devices

2017 ◽  
Author(s):  
D. Zudhistira ◽  
V. Viswanathan ◽  
V. Narang ◽  
J.M. Chin ◽  
S. Sharang ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Dielectric Films ◽  
Planar Surface ◽  
Chemical Methods ◽  
Root Cause ◽  
Essential Step ◽  
Dielectric Layers ◽  
Wet Chemical ◽  
20 Nm ◽  
Low K

Abstract Deprocessing is an essential step in the physical failure analysis of ICs. Typically, this is accomplished by techniques such as wet chemical methods, RIE, and mechanical manual polishing. Manual polishing suffers from highly non-uniform delayering particularly for sub 20nm technologies due to aggressive back-end-of-line scaling and porous ultra low-k dielectric films. Recently gas assisted Xe plasma FIB has demonstrated uniform delayering of the metal and dielectric layers, achieving a planar surface of heterogeneous materials. In this paper, the successful application of this technique to delayer sub-20 nm microprocessor chips with real defects to root cause the failure is presented.

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