On the Structure and Contraction of Striped Muscular Fibre of the Crab and Lobster

1891 ◽  
Vol 17 ◽  
pp. 146-149 ◽  
Author(s):  
William Rutherford
Keyword(s):  
International Medical ◽  
Muscular Fibre ◽  
Structural Elements ◽  
Striped Muscle ◽  
Large Size

(Abstract)The author gave an account of the microscopical appearances of striped muscle of the crab and lobster. The muscle of the crab and lobster is suitable for investigation because of the comparatively large size of the structural elements, and the readiness with which the sarcous matter can be fixed and otherwise prepared in different conditions. The author is entirely opposed to the opinions expressed by Melland, and more recently by Gehuchten, regarding the structure of the sarcous matter, and maintains, as he did at the International Medical Congress in 1881 (Transactions International Medical Congress, 1881, vol. i. p. 270), that the sarcous matter essentially consists of contractile fibrils, with an interstitial substance between them—an opinion previously expressed by Kölliker and others, and recently supported by Rollett.

Works Shaped by Family

Born to Write ◽  
2020 ◽  
pp. 58-136
Author(s):  
Neil Kenny
Keyword(s):  
Family Dynamics ◽  
Structural Elements ◽  
Large Size ◽  
Printed Books ◽  
The Future

Family literature ranged from works of humanist scholarship to history, to poetry, to engineering. There was considerable imitation by relatives of the practices, disciplines, and genres that preceding relatives had adopted. More generally in family literature, certain preoccupations recurred, for example with history, time, nobility, genealogy, and transmission. Certain structural elements of printed-book objects were fostered by family dynamics: large size; paratexts; bricolage. This chapter surveys some ways in which the preoccupation with propelling families into the future shaped printed books. The survey is of a spectrum of overlapping possibilities: it runs from volumes that were largely presented as being by a single literary producer to ones that were largely presented as being by a family collective.

Heterogeneous Shrinkage of High-Strength Concrete by the Volume of Large-Size Structural Elements

2015 ◽  
Vol 723 ◽  
pp. 445-450 ◽  
Author(s):  
Volodymyr I. Korsun ◽  
Nikolai Vatin ◽  
Artem Korsun ◽  
Darya Nemova
Keyword(s):  
Scale Effect ◽  
Experimental Research ◽  
High Strength Concrete ◽  
High Strength ◽  
Shrinkage Strain ◽  
Structural Elements ◽  
Strength Concrete ◽  
Large Size

The article introduces results of the experimental research of the influence of the scale effect on the shrinkage strain of high-strength concrete of C70/85 class as well as recommendations for accounting in practical calculations of the scale effect influence on the characteristics under research.

XXVII. On the distribution of nerves to the elementary fibres of striped muscle

1860 ◽  
Vol 150 ◽  
pp. 611-619 ◽  
Keyword(s):  
Nerve Fibre ◽  
Muscular Fibre ◽  
Nerve Fibres ◽  
Striped Muscle ◽  
Axis Cylinder ◽  
Single Nucleus

No branch of minute anatomy has received a larger share of attention than the anatomy of striped muscle, and probably no one point has been more carefully investigated than the distribution of nerve-fibres to this important tissue. Very different conclusions have been arrived at, and the various questions at issue have not yet been determined satisfactorily. For the different views entertained with reference to the mode of termination of nerve-fibres I must refer to the treatises on minute anatomy, and especially to Professor Kölliker’s work just published, where a summary of the results of numerous investigations will be found. Kühne’s Observations . The most recent observations are probably those of Kühne, who states that the nerve-fibre can be traced up to the sarcolemma. He concludes, with some other observers, that in the muscles of insects the axis cylinder of the nerve-fibre penetrates this transparent structure, and is connected with the rows of nuclei which are imbedded in the substance of the muscular fibre and lie amongst the fibrillæ. As will be observed by reference to Kühne’s drawings, these points are very indistinctly, and, if I may so say, diffidently represented. Like Kühne himself, I have quite failed to demonstrate in vertebrate animals the arrangement he described in insects. It may be remarked that nuclei amongst the fibrillæ are very abundant in some fishes and reptiles (especially the frog) whose muscles are sparingly supplied with nerves, while in the muscular fibre of many birds and mammalia which are very abundantly supplied, not a single nucleus can be demonstrated in the interior of the fibre. It seems hardly likely that the relation between the nerves and the contractile elements of the tissue should be closer in these cold-blooded, and comparatively inactive vertebrata, than in birds and mammals. The nuclei amongst the fibrillæ of the muscles of vertebrate animals are clearly not connected with nerves.

Coherency loss in γ' precipitates in nickel-base superalloy

1983 ◽  
Vol 41 ◽  
pp. 244-245
Author(s):  
R. A. Ricks ◽  
Angus J. Porter
Keyword(s):  
Lattice Mismatch ◽  
Lattice Parameter ◽  
Nickel Base Superalloy ◽  
Large Size ◽  
The Matrix ◽  
Nimonic 80A ◽  
Interfacial Dislocations ◽  
Nickel Base ◽  
Coherency Loss ◽  
Nimonic 115

During a recent investigation concerning the growth of γ' precipitates in nickel-base superalloys it was observed that the sign of the lattice mismatch between the coherent particles and the matrix (γ) was important in determining the ease with which matrix dislocations could be incorporated into the interface to relieve coherency strains. Thus alloys with a negative misfit (ie. the γ' lattice parameter was smaller than the matrix) could lose coherency easily and γ/γ' interfaces would exhibit regularly spaced networks of dislocations, as shown in figure 1 for the case of Nimonic 115 (misfit = -0.15%). In contrast, γ' particles in alloys with a positive misfit could grow to a large size and not show any such dislocation arrangements in the interface, thus indicating that coherency had not been lost. Figure 2 depicts a large γ' precipitate in Nimonic 80A (misfit = +0.32%) showing few interfacial dislocations.

Automatic analysis of Kikuchi diffraction patterns

1994 ◽  
Vol 52 ◽  
pp. 900-901
Author(s):  
H. Weiland ◽  
D. P. Field
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Spatial Resolution ◽  
Relevant Information ◽  
Crystalline Materials ◽  
Large Size ◽  
Transmission Electron ◽  
New Type ◽  
Diffraction Patterns ◽  
Orientation Determination

Recent advances in the automatic indexing of backscatter Kikuchi diffraction patterns on the scanning electron microscope (SEM) has resulted in the development of a new type of microscopy. The ability to obtain statistically relevant information on the spatial distribution of crystallite orientations is giving rise to new insight into polycrystalline microstructures and their relation to materials properties. A limitation of the technique in the SEM is that the spatial resolution of the measurement is restricted by the relatively large size of the electron beam in relation to various microstructural features. Typically the spatial resolution in the SEM is limited to about half a micron or greater. Heavily worked structures exhibit microstructural features much finer than this and require resolution on the order of nanometers for accurate characterization. Transmission electron microscope (TEM) techniques offer sufficient resolution to investigate heavily worked crystalline materials.Crystal lattice orientation determination from Kikuchi diffraction patterns in the TEM (Figure 1) requires knowledge of the relative positions of at least three non-parallel Kikuchi line pairs in relation to the crystallite and the electron beam.

Immunoprobe localization in mammalian embryos

1990 ◽  
Vol 48 (3) ◽  
pp. 32-33
Author(s):  
Patricia G. Calarco ◽  
Margaret C. Siebert
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Thin Sections ◽  
Relative Lack ◽  
Large Size ◽  
Mammalian Embryos ◽  
Antigen Localization ◽  
Difficult Challenge ◽  
Lowicryl K4m ◽  
Fertilized Egg

Visualization of preimplantation mammalian embryos by electron microscopy is difficult due to the large size of the ircells, their relative lack of internal structure, and their highly hydrated cytoplasm. For example, the fertilized egg of the mouse is a single cell of approximately 75μ in diameter with little organized cytoskelet on and apaucity ofor ganelles such as endoplasmic reticulum (ER) and Golgi material. Thus, techniques that work well on tissues or cell lines are often not adaptable to embryos at either the LM or EM level.Over several years we have perfected techniques for visualization of mammalian embryos by LM and TEM, SEM and for the pre-embedding localization of antigens. Post-embedding antigenlocalization in thin sections of mouse oocytes and embryos has presented a more difficult challenge and has been explored in LR White, LR Gold, soft EPON (after etching of sections), and Lowicryl K4M. To date, antigen localization has only been achieved in Lowicryl-embedded material, although even with polymerization at-40°C, the small ER vesicles characteristic of embryos are unrecognizable.

Structural phenomena in the growth of carbon nanotubes

1993 ◽  
Vol 51 ◽  
pp. 750-751
Author(s):  
Jun Jiao
Keyword(s):  
Carbon Nanotubes ◽  
Growth Mechanism ◽  
Carbonaceous Material ◽  
Cluster Growth ◽  
Structural Elements ◽  
Rich Variety ◽  
Different Shapes ◽  
Point To Point

HREM studies of the carbonaceous material deposited on the cathode of a Huffman-Krätschmer arc reactor have shown a rich variety of multiple-walled nano-clusters of different shapes and forms. The preparation of the samples, as well as the variety of cluster shapes, including triangular, rhombohedral and pentagonal projections, are described elsewhere.The close registry imposed on the nanotubes, focuses attention on the cluster growth mechanism. The strict parallelism in the graphitic separation of the tube walls is maintained through changes of form and size, often leading to 180° turns, and accommodating neighboring clusters and defects. Iijima et. al. have proposed a growth scheme in terms of pentagonal and heptagonal defects and their combinations in a hexagonal graphitic matrix, the first bending the surface inward, and the second outward. We report here HREM observations that support Iijima’s suggestions, and add some new features that refine the interpretation of the growth mechanism. The structural elements of our observations are briefly summarized in the following four micrographs, taken in a Hitachi H-8100 TEM operating at an accelerating voltage of 200 kV and with a point-to-point resolution of 0.20 nm.

Vibration Isolator System for Electron Microscope

1990 ◽  
Vol 48 (1) ◽  
pp. 182-183
Author(s):  
K. Ohi ◽  
M. Mizuno ◽  
T. Kasai ◽  
Y. Ohkura ◽  
K. Mizuno ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Magnetic Fields ◽  
Environmental Conditions ◽  
Vibration Isolator ◽  
Air Conditioners ◽  
Vibration Isolators ◽  
Large Size ◽  
Electron Microscopes

In recent years, with electron microscopes coming into wider use, their installation environments do not necessarily give their performance full play. Their environmental conditions include air-conditioners, magnetic fields, and vibrations. We report a jointly developed entirely new vibration isolator which is effective against the vibrations transmitted from the floor.Conventionally, large-sized vibration isolators which need the digging of a pit have been used. These vibration isolators, however, are large present problems of installation and maintenance because of their large-size.Thus, we intended to make a vibration isolator which1) eliminates the need for changing the installation room2) eliminates the need of maintenance and3) are compact in size and easily installable.

Designing TIMP (tissue inhibitor of metalloproteinases) variants that are selective metalloproteinase inhibitors

2003 ◽  
Vol 70 ◽  
pp. 201-212 ◽  
Author(s):  
Hideaki Nagase ◽  
Keith Brew
Keyword(s):  
Three Dimensional ◽  
Therapeutic Interventions ◽  
Tissue Inhibitors Of Metalloproteinases ◽  
Structural Basis ◽  
Structural Elements ◽  
Ridge Structure ◽  
Extracellular Matrix Components ◽  
Metalloproteinase Inhibitors ◽  
The Matrix ◽  
A Disintegrin And Metalloproteinase

The tissue inhibitors of metalloproteinases (TIMPs) are endogenous inhibitors of the matrix metalloproteinases (MMPs), enzymes that play central roles in the degradation of extracellular matrix components. The balance between MMPs and TIMPs is important in the maintenance of tissues, and its disruption affects tissue homoeostasis. Four related TIMPs (TIMP-1 to TIMP-4) can each form a complex with MMPs in a 1:1 stoichiometry with high affinity, but their inhibitory activities towards different MMPs are not particularly selective. The three-dimensional structures of TIMP-MMP complexes reveal that TIMPs have an extended ridge structure that slots into the active site of MMPs. Mutation of three separate residues in the ridge, at positions 2, 4 and 68 in the amino acid sequence of the N-terminal inhibitory domain of TIMP-1 (N-TIMP-1), separately and in combination has produced N-TIMP-1 variants with higher binding affinity and specificity for individual MMPs. TIMP-3 is unique in that it inhibits not only MMPs, but also several ADAM (a disintegrin and metalloproteinase) and ADAMTS (ADAM with thrombospondin motifs) metalloproteinases. Inhibition of the latter groups of metalloproteinases, as exemplified with ADAMTS-4 (aggrecanase 1), requires additional structural elements in TIMP-3 that have not yet been identified. Knowledge of the structural basis of the inhibitory action of TIMPs will facilitate the design of selective TIMP variants for investigating the biological roles of specific MMPs and for developing therapeutic interventions for MMP-associated diseases.

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