scholarly journals Known and Unknown Features of Hair Cuticle Structure: A Brief Review

Cosmetics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 32 ◽  
Author(s):  
George E. Rogers
Keyword(s):  
Electron Microscope ◽  
Surface Shape ◽  
Internal Layers ◽  
Industrial Processing ◽  
Membrane Complex ◽  
Central Protein ◽  
Associated Proteins ◽  
Keratin Filament ◽  
Lipid Surface ◽  
The Stability

The cuticle is the outermost layer of overlapping flattened cells of hair and has been subjected to many years of study to understand its structure and how it develops in the follicle. The essential function of the cuticle with its tough inelastic protein content is to protect the inner cortex that provides the elastic properties of hair. Progress in our knowledge of hair came from studies with the electron microscope, initially transmission electron microscopy (TEM) for internal structure and later the scanning electron microscope (SEM) for cuticle surface shape and for investigating changes caused by various environmental influences such as cosmetic treatments and industrial processing of wool. Other physical techniques have been successfully applied in conjunction with proteomics. The outstanding internal features of the cuticle cells are the internal layers consisting of keratin filament proteins and the keratin-associated proteins. The stability and physical toughness of the cuticle cell is partly accounted for by the high content of disulphide crosslinking. The material between the cells that holds them tightly together, the cell membrane complex, consists of a layer of lipid on both sides of a central protein layer. The lipid contains 18-methyleicosanoic acid that is part of the hydrophobic lipid surface of hair. For the past decade there have been aspects that remained unanswered because they are difficult to study. Some of these are discussed in this brief review with suggestions for experimental approaches to shed more light.

An Analysis of Dissociation of Molecules in a High Resolution Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 486-487
Author(s):  
Mihir Parikh
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Cross Sections ◽  
Resolving Power ◽  
Peak Intensity ◽  
Molecular Film ◽  
Resolution Electron ◽  
Dissociation Cross Section ◽  
High Resolution Electron Microscope ◽  
The Stability

It is well known that the resolution of bio-molecules in a high resolution electron microscope depends not just on the physical resolving power of the instrument, but also on the stability of these molecules under the electron beam. Experimentally, the damage to the bio-molecules is commo ly monitored by the decrease in the intensity of the diffraction pattern, or more quantitatively by the decrease in the peaks of an energy loss spectrum. In the latter case the exposure, EC, to decrease the peak intensity from IO to I’O can be related to the molecular dissociation cross-section, σD, by EC = ℓn(IO /I’O) /ℓD. Qu ntitative data on damage cross-sections are just being reported, However, the microscopist needs to know the explicit dependence of damage on: (1) the molecular properties, (2) the density and characteristics of the molecular film and that of the support film, if any, (3) the temperature of the molecular film and (4) certain characteristics of the electron microscope used

The Photoluminescence Enhancement and Stability of Porous Silicon by Cathodic Reduction and Acid Treatment

2014 ◽  
Vol 887-888 ◽  
pp. 458-461
Author(s):  
Chang Qing Li ◽  
Kun Wang ◽  
Pei Jia Liu ◽  
Qi Ming
Keyword(s):  
Electron Microscope ◽  
Porous Silicon ◽  
Acid Treatment ◽  
Cathodic Reduction ◽  
Luminescence Properties ◽  
Sem Images ◽  
Photoluminescence Enhancement ◽  
The Stability ◽  
Scanning Electron ◽  
Cathode Reduction

Porous silicon (PSi) was fabricated by using electrochemical anodic etching method. Then acid treatment and cathode reduction treatment were employed to improve the luminescence properties and stability of PSi material. Photoluminescence (PL) measurements and scanning electron microscope (SEM) were used to observe the luminescence properties and microstructure of samples, respectively. The results of PL measurements showed that the PL intensity and the stability of luminescence of samples after cathodic reduction and acid treatment were significantly improved. The SEM images showed that the porosity of PSi may be increased through the cathodic reduction treated.

scholarly journals The Putative RNA-Binding Protein Nrp1 Promotes the Loading of Kinesin-14/Klp2 to the Mitotic Spindle and Is Sequestered Into Heat-Induced Protein Aggregates in Fission Yeast

2021 ◽  
Author(s):  
Masashi Yukawa ◽  
Mitsuki Ohishi ◽  
Yusuke Yamada ◽  
Takashi Toda
Keyword(s):  
Fission Yeast ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Protein Aggregates ◽  
Associated Proteins ◽  
Spindle Microtubules ◽  
The Stability ◽  
And Function ◽  
Post Transcriptional Regulation

Cells form a bipolar spindle during mitosis to ensure accurate chromosome segregation. Proper spindle architecture is established by a set of kinesin motors and microtubule-associated proteins. In most eukaryotes, kinesin-5 motors are essential for this process, and genetic or chemical inhibition of their activity leads to the emergence of monopolar spindles and cell death. However, these deficiencies can be rescued by simultaneous inactivation of kinesin-14 motors, as they counteract kinesin-5. We conducted detailed genetic analyses in fission yeast to understand the mechanisms driving spindle assembly in the absence of kinesin-5. Here we show that deletion of the nrp1 gene, which encodes a putative RNA-binding protein with unknown function, can rescue temperature sensitivity caused by cut7-22, a fission yeast kinesin-5 mutant. Interestingly, kinesin-14/Klp2 levels on the spindles in the cut7 mutants were significantly reduced by the nrp1 deletion, although the total levels of Klp2 and the stability of spindle microtubules remained unaffected. Moreover, RNA-binding motifs of Nrp1 are essential for its cytoplasmic localization and function. We have also found that a portion of Nrp1 is spatially and functionally sequestered by chaperone-based protein aggregates upon mild heat stress and limits cell division at high temperatures. We propose that Nrp1 might be involved in post-transcriptional regulation through its RNA-binding ability to promote the loading of Klp2 on the spindle microtubules.

scholarly journals Fabrication and evaluation of slow-release lignin-based avermectin nano-delivery system with UV-shielding property

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dongmei Mo ◽  
Xiangying Li ◽  
Yong Chen ◽  
Yang Jiang ◽  
Chunfang Gan ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Controlled Release ◽  
Delivery System ◽  
High Speed ◽  
Large Scale ◽  
Diazonium Salt ◽  
Sodium Lignosulfonate ◽  
Ultrasonic Dispersion ◽  
Transmission Electron ◽  
The Stability

AbstractNanopesticide is one of the best pesticide formulation technologies to overcome the disadvantages of traditional pesticides, which has received great attention from the international community. Using high-speed emulsification and ultrasonic dispersion technology, an avermectin nano-delivery system (Av-NDs) with a particle size of 80–150 nm was prepared through embedding the pesticide molecule utilizing the cross-linking reaction between sodium lignosulfonate and p-phenylenediamine diazonium salt. The formulation and composition of Av-NDs were optimized, the morphology of Av-NDs was analyzed by scanning electron microscope, transmission electron microscope and dynamic light scattering, and the structure of Av-NDs was characterized by UV, IR and 1H NMR. Anti-photolysis and controlled-release tests show that the stability of Av-NDs is 3–4 times of the original avermectin (Av) and possesses the pH-responsive controlled release property. Furthermore, the insecticidal activity of Av-NDs is better than that of avermectin suspension concentrate (Av-SC). The Av-NDs with anti-photolysis and controlled-release characteristics is suitable for large-scale industrial production and is capable to be utilized as effective insecticide in the field.

On the Design of Contact Member Surface Shape of Bolted Joints to Minimize Clamping Load Loss

2018 ◽  
Author(s):  
Linbo Zhu ◽  
Yifei Hou ◽  
Abdel-Hakim Bouzid ◽  
Jun Hong
Keyword(s):  
Contact Surface ◽  
High Performance ◽  
Thermal Loading ◽  
Structural Integrity ◽  
Bolted Joints ◽  
Surface Shape ◽  
Geometrical Shape ◽  
Joint Surfaces ◽  
Joint Contact ◽  
The Stability

Metal to metal contact between joint surfaces is widely used in bolted joints to obtain a rigid and a high performance connection. However, a significant amount of clamping load is lost when the joint is subjected to mechanical and thermal loading including creep and fatigue. In practice, to prevent bolt loosening, additional parts such as spring washers, double nut, spring lock washers, Nyloc nut and so on are used. Those methods are costly and influence the stability of the joint and affect its structural integrity. It is well established that a small compression displacement in clamping parts leads to a big clamping load loss in stiff joints. This paper discusses the relationship between connection stiffness and clamping load and presents a method that improves clamping load retention during operation by a careful design of the member contact surface shape. A single bolted joint with two clamping parts is modeled using finite element method (FEM). A method is proposed to obtain a specific stiffness by an optimized geometrical shape of the joint contact surfaces. The result shows that the contact surface shape based on a gradually varying gap can improve the retention of the initial clamping load. Furthermore, a formula of the connection stiffness based on the curve fitting technique is proposed to predict residual clamping load under different external load and loosening.

scholarly journals Gliding Associated Proteins Play Essential Roles during the Formation of the Inner Membrane Complex of Toxoplasma gondii

2016 ◽  
Vol 12 (2) ◽  
pp. e1005403 ◽  
Author(s):  
Clare R. Harding ◽  
Saskia Egarter ◽  
Matthew Gow ◽  
Elena Jiménez-Ruiz ◽  
David J. P. Ferguson ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Inner Membrane ◽  
Membrane Complex ◽  
Associated Proteins ◽  
Inner Membrane Complex

Green Synthesis of Platinum-encapsulated Nickel Nanocatalyst and Its Microstructure Evaluation

2009 ◽  
Vol 1213 ◽  
Author(s):  
Iliana Medina-Ramirez ◽  
Xu-Bin Pan ◽  
Sajid Bashir ◽  
Jingbo Louise Liu
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Particle Size Distribution ◽  
Colloidal Suspension ◽  
Cost Effective ◽  
X Ray ◽  
Microstructure Evaluation ◽  
Transmission Electron ◽  
Colloidal Method ◽  
The Stability

AbstractPlatinum (Pt) is the most efficient and highly utilized electrocatalsyt; however its high cost hinders its widespread use as a stand-alone catalyst. To remedy this problem, a nickel (Ni) encapsulated by Pt (NiⓔPt) nanocatalyst was fabricated using a cost-effective green colloidal method. The NiⓔPt nanoparticles (NPs) were then characterized using transmission electron microscope (TEM) equipped with X-ray energy dispersive spectroscopy (EDS), and X-ray powder diffraction (XRD) to determine the particle size distribution, morphology, elemental composition, and crystalline phase structure. The surface energetic was also measured using ZetaPALS™ to identify the stability of the colloidal suspension.

scholarly journals Keratins determine network stress responsiveness in reconstituted actin-keratin filament systems

2020 ◽  
Author(s):  
Iman Elbalasy ◽  
Paul Mollenkopf ◽  
Cary Tutmarc ◽  
Harald Herrmann ◽  
Jörg Schnauß
Keyword(s):  
Mechanical Response ◽  
Epithelial Mesenchymal Transition ◽  
Viscoelastic Behavior ◽  
Mesenchymal Transition ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
Network Partner ◽  
Keratin Filament ◽  
The Stability

The cytoskeleton is a major determinant of cell mechanics, a property that is altered during many pathological situations. To understand these alterations, it is essential to investigate the interplay between the main filament systems of the cytoskeleton in the form of composite networks. Here, we investigate the role of keratin intermediate filaments (IFs) in network strength by studying in vitro reconstituted actin and keratin 8/18 composite networks via bulk shear rheology. We co-polymerized these structural proteins in varying ratios and recorded how their relative content affects the overall mechanical response of the various composites. For relatively small deformations, we found that all composites exhibited an intermediate linear viscoelastic behavior compared to that of the pure networks. In stark contrast, the composites displayed increasing strain stiffening behavior as a result of increased keratin content when larger deformations were imposed. This strain stiffening behavior is fundamentally different from behavior encountered with vimentin IF as a composite network partner for actin. Our results provide new insights into the mechanical interplay between actin and keratin in which keratin provides reinforcement to actin. This interplay may contribute to the overall integrity of cells, providing an explanation for the stability of stressed epithelial tissues due to their high keratin contents. Additionally, this helps us to understand the physiological necessity to exchange IF systems during epithelial-mesenchymal transition (EMT) in order to suppress strain stiffening of the network, making cells more elastic and, thus, facilitating their migration through dense tissues.

scholarly journals Multivalent interactions drive the Toxoplasma AC9:AC10:ERK7 complex to concentrate ERK7 in the apical cap

2022 ◽  
Author(s):  
Peter S Back ◽  
William J O'Shaughnessy ◽  
Andy S Moon ◽  
Pravin S Dewangan ◽  
Michael L Reese ◽  
...  
Keyword(s):  
Map Kinase ◽  
Kinase Activity ◽  
Pairwise Interaction ◽  
Inner Membrane ◽  
Membrane Complex ◽  
Apical Complex ◽  
Multivalent Interactions ◽  
Inner Membrane Complex ◽  
Parasite Motility ◽  
The Stability

The Toxoplasma inner membrane complex (IMC) is a specialized organelle that is crucial for the parasite to establish an intracellular lifestyle and ultimately cause disease. The IMC is composed of both membrane and cytoskeletal components, further delineated into the apical cap, body, and basal subcompartments. The apical cap cytoskeleton was recently demonstrated to govern the stability of the apical complex, which controls parasite motility, invasion, and egress. While this role was determined by individually assessing the apical cap proteins AC9, AC10, and the MAP kinase ERK7, how the three proteins collaborate to stabilize the apical complex is unknown. In this study, we use a combination of deletion analyses and yeast-2-hybrid experiments to establish that these proteins form an essential complex in the apical cap. We show that AC10 is a foundational component of the AC10:AC9:ERK7 complex and demonstrate that the interactions among them are critical to maintain the apical complex. Importantly, we identify multiple independent regions of pairwise interaction between each of the three proteins, suggesting that the AC9:AC10:ERK7 complex is organized by multivalent interactions. Together, these data support a model in which multiple interacting domains enable the oligomerization of the AC9:AC10:ERK7 complex and its assembly into the cytoskeletal IMC, which serves as a structural scaffold that concentrates ERK7 kinase activity in the apical cap.

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