The Gametophore and Sporophyte of Mittenia plumula (Mitt.) Lindb

1961 ◽  
Vol 9 (2) ◽  
pp. 124 ◽  
Author(s):  
IG Stone
Keyword(s):  
Early Development ◽  
Outer Layer ◽  
Middle Layer ◽  
Anticlinal Wall ◽  
Outermost Layer ◽  
Periclinal Walls

An account is given of the gametophore and sporophyte of Mittenia plumula, stressing those features which have not previously been described. The moss has a highly refractive lenticular protonema. There is variation in the arrangement of leaves on sterile and fertile shoots, a shoot may develop one or more side shoots at its base, and hairs are present in the axils of leaves. The capsule has a few small stomata at the base, and the inner peristome consists of 28-32 processes. The double peristome of Mittenia plumula originates from three concentric layers of cells, the two innermost layers of the amphithecium and the outermost layer of the endothecium. In all other members of the Bryales whose examination has included early development, the peristome has been found to develop from amphithecial tissue only. The 16 outer peristorno teeth are forined on the periclinwl walls separating the two outer peristome layers, thickening being laid down on the inner walls of the outer layer, which is composed of 16 cells, and in adjoining posit'ions on tho outor walls of the middle layer, which is composed of eight cells. The inner peristome processes are formed on the periclinal walls separating the middle from the inner peristome layer (the latter being endothecial in origin). Thickening is laid down on the inner walls of the middle layer at positions contiguous with the junctions of the anticlinal walls of the inner layer, which is composed of 24-28 cells. Extra processes usually develop where the anticlinal wall is part of the original quadrant wall of the embryo. A smaller amount of thickening is then contributed to the processes from the inner peristome layer. Variations in the development of the inner peristome are discussed, and a comparison is made with development of the double peristome of other members of the Diplolepideae.

Ultrastructure of the envelopes of resistant and nonresistant Daphnia eggs

1979 ◽  
Vol 57 (9) ◽  
pp. 1773-1777 ◽  
Author(s):  
Lisa A. Seidman ◽  
John H. Larsen Jr.
Keyword(s):  
Plasma Membrane ◽  
Developmental Stage ◽  
Early Development ◽  
Outer Layer ◽  
Middle Layer ◽  
Outer Wall ◽  
Egg Envelope ◽  
Middle Component

During early development, the nonresistant egg of Daphnia had an outer wall of [Formula: see text], and an inner wall approximately the thickness of the plasma membrane. In the same genus at a comparable developmental stage, resistant eggs were surrounded by a three-layered envelope, [Formula: see text] thick. Although the outer layer [Formula: see text] of the latter appeared similar to the outer wall of the nonresistant egg, the middle layer [Formula: see text] resembled the crustacean procuticle. The outer layer developed before the formation of the middle component, and both structures were absent after development resumed. This suggests that the resistant egg envelope is characterized by an additional embryonic cuticle and molt.

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.

Histopathology of the A1 Pulley in Adult Trigger Fingers

2007 ◽  
Vol 32 (5) ◽  
pp. 556-559 ◽  
Author(s):  
M. C. SBERNARDORI ◽  
P. BANDIERA
Keyword(s):  
Connective Tissue ◽  
Middle Layer ◽  
Laminar Structure ◽  
Loose Connective Tissue ◽  
Control Series ◽  
Outermost Layer ◽  
Additional Layer ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
A1 Pulley

The histopathology of the central parts of 40 A1 pulleys from adult patients with primary trigger fingers was studied using light and transmission electron microscopes and the findings were compared with those in a control series of 10 normal A1 pulleys. The evaluation of the normal A1 pulley revealed a bi-laminar structure. The deepest layer was composed of dense normal connective tissue. The outermost layer was formed by loose connective tissue. In trigger digits, it was possible to identify a tri-laminar structure. The deepest layer was composed of irregular connective tissue, formed by small collagen fibres and abundant extracellular matrix. A considerable amount of chondroid-metaplasia was present in this layer. The middle layer contained dense, normal connective tissue with some fibrocytes. The outermost layer was formed of loose connective tissue. In conclusion, there was an additional layer in the A1 pulley in pathological cases which was not present in normal pulleys.

scholarly journals The three muscle layers in the pyloric sphincter and their possible function during antropyloroduodenal motility

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mi-Sun Hur ◽  
Seunggyu Lee ◽  
Tong Mook Kang ◽  
Chang-Seok Oh
Keyword(s):  
Outer Layer ◽  
Longitudinal Muscle ◽  
Middle Layer ◽  
Comprehensive Approach ◽  
Pyloric Sphincter ◽  
Muscular Tissue ◽  
Micro Ct ◽  
Circular Layer ◽  
Korean Adult ◽  
Longitudinal Layer

AbstractThis study was conducted to determine the muscular arrangement of the human pyloric sphincter using a comprehensive approach that involved microdissection, histology, and microcomputed tomography (micro‐CT). The stomachs of 80 embalmed Korean adult cadavers were obtained. In all specimens, loose muscular tissue of the innermost aspect of the sphincter wall ran aborally, forming the newly found inner longitudinal muscle bundles, entered the duodenum, and connected with the nearby circular bundles. In all specimens, approximately one-third of the outer longitudinal layer of the sphincter entered its inner circular layer, divided the circular layer into several parts, and finally connected with the circular bundles. Anatomical findings around the sphincter were confirmed in micro-CT images. The sphincter wall comprised three layers: an inner layer of longitudinal bundles, a middle layer of major circular and minor longitudinal bundles, and an outer layer of longitudinal bundles. The stomach outer longitudinal bundles were connected to the sphincter circular bundles. The inner longitudinal bundles of the sphincter were connected to the adjacent circular bundles of the duodenum.

scholarly journals Validation of Age Estimation in the Harp Seal, Phoca groenlandica, Using Dentinal Annuli

1983 ◽  
Vol 40 (9) ◽  
pp. 1430-1441 ◽  
Author(s):  
W. D. Bowen ◽  
D. E. Sergeant ◽  
T. Øritsland
Keyword(s):  
Outer Layer ◽  
Age Estimation ◽  
Transverse Section ◽  
Age Determination ◽  
Middle Layer ◽  
Harp Seal ◽  
Growth Layer ◽  
Phoca Groenlandica ◽  
Incremental Growth ◽  
Absolute Age

We investigated the validity and accuracy of age estimation in harp seals, Phoca groenlandica, using a sample of 155 known-age teeth from seals age 3 mo to 10 yr. Under transmitted light, transverse sections of harp seal canine teeth showed distinct incremental growth layers (IGLs) in the dentine. The first growth-layer group (GLG), representing Ist-year growth, consists of two IGLs: an outer layer of opaque dentine, bounded by the neonatal line, and an inner layer of translucent dentine. Subsequent GLGs, each representing 1 yr of growth, generally consist of three IGLs: an outer layer of interglobular dentine deposited during the annual molt in April, a middle layer of opaque dentine formed during the northward spring migration (May–June), and an inner layer of translucent dentine formed from July to March. We show that dentinal GLGs can be used to estimate the absolute age of harp seals. The accuracy of the method decreases with age. Only 72.4% of estimates of 0-group seals were correct using only transverse sections. These errors were virtually eliminated (99.0% correct age determination) when the tooth root was examined. Based on a single examination of a transverse section, the probabilities of correctly estimating age are 0.983, 0.889, 0.817, and 0.553 at ages 1, 2, 3, and 4 + yr, respectively, when clearly inaccurate tag-tooth associations are omitted. The respective probabilities are only slightly higher when age is based on the average of five blind readings, being 1.0, 0.889, 0.833, and 0.625. Beyond age 3 yr, existing data are insufficient to estimate reliably the accuracy of age determined by counting GLGs.

The Cuticle of Cysticerci of Taenia Saginata, T. Hydatigena, and T. Pisiformis

1963 ◽  
Vol s3-104 (65) ◽  
pp. 141-144
Author(s):  
E. H. SIDDIQUI
Keyword(s):  
Electron Microscopy ◽  
Outer Layer ◽  
Middle Layer ◽  
Taenia Saginata ◽  
Optical And Electron Microscopy

The structure of the cuticle of the cysticerci of 3 species of Taenia was studied by means of optical and electron microscopy. In all 3 species the cuticle is composed of 3 layers and covered with hair-like processes. The middle layer, which comprises the bulk of the cuticle, varies in thickness from head to bladder, but there are no differences in thickness between the species studied. The hairs are composed of a core representing an extension of the middle layer and are covered by a continuation of the outer layer. The arrangement of these hairs varies in the species studied.

Analysis on Failure of Oxide Layer of T91 High Temperature Superheater Tube

2014 ◽  
Vol 1070-1072 ◽  
pp. 505-511
Author(s):  
Shan Shan Zhang ◽  
Guang Chen ◽  
Chang Ming Li ◽  
Da Hu
Keyword(s):  
High Temperature ◽  
Dissolved Oxygen ◽  
Oxide Layer ◽  
Outer Layer ◽  
Oxidation Mechanism ◽  
Middle Layer ◽  
Compact Structure ◽  
Protective Properties ◽  
Superheater Tube ◽  
Temperature Operating

The reason why the failure protective properties of the oxide layer of T91 high temperature superheater tube were analyzed in this study. The microstructure of the oxide layer of T91 high temperature superheater tube was observed by scanning electron microscope (SEM) and the morphological features of it was also analyzed. The concentrations of alloy elements in the section of internal tube were quantitatively analyzed using Energy Dispersive System (EDS). The results showed that the oxide layer of T91 tube can be divided into three layers: inner layer, middle layer and outer layer. The inner layer was formed by chromium rich oxide with compact structure. The middle layer was made up by porous oxide with loose structure. The outer layer was identified as Fe2O3. When the content of dissolved oxygen in steam was excessive, the apparent peeling marks will be appeared in the oxide layer of T91 high temperature superheater tube and the distribution of alloy elements in the oxide layer will present obvious proliferation, migration and enrichment phenomenon. Two different mechanisms (steam oxidation mechanism and oxygen oxidation mechanism) will exercise different influences on the structure and protective properties of the oxide layer: when steam contained dissolved oxygen, the oxide layer will be peroxidated by steam and the structure of oxide layer will be broken; When the tube was over-temperature operating, the oxide layer will be oxidated by oxygen.

Development of tri-layer knitted fabrics for shuttle badminton players

2017 ◽  
Vol 48 (4) ◽  
pp. 738-760 ◽  
Author(s):  
T Suganthi ◽  
P Senthilkumar
Keyword(s):  
Thermal Comfort ◽  
Outer Layer ◽  
Thermal Environment ◽  
Middle Layer ◽  
Objective Evaluation ◽  
Knitted Fabrics ◽  
Vapour Permeability ◽  
Moisture Management ◽  
Insensible Perspiration ◽  
Knitted Structure

Thermo-physiological comfort of the fabric is attained through the ability of managing heat and transmission of sensible and insensible perspiration. An investigation on influence of tri-layer knitted structure on thermal comfort characteristics of layered knitted fabrics was carried out. Three tri-layer knitted structures were developed in which inner layer was made up of micro-fibre polyester and outer layer was made up of modal yarn. The yarn used in the middle layer was changed to either micro-fibre polyester or polyester or acrylic yarn. The thermal comfort characteristics such as thermal conductivity, air permeability, water vapour permeability, wicking, moisture absorbency, drying rate and moisture management properties have been analysed. Wear trial was conducted for shuttle badminton players and they were ranked using thermal environment subjective judgement scale. Tri-layer knitted structure with micro-fibre polyester in the inner and middle layer and modal in the outer layer showed better thermal comfort characteristics both by objective evaluation and wear trial method compared to polyester or acrylic in the middle layer and is preferable for shuttle badminton sportswear.

Sandwich crystals of butyl paraben

CrystEngComm ◽  
2014 ◽  
Vol 16 (37) ◽  
pp. 8863-8873 ◽  
Author(s):  
Huaiyu Yang ◽  
Hong Chen ◽  
Åke C. Rasmuson
Keyword(s):  
Outer Layer ◽  
Middle Layer ◽  
Scale Size

Sandwich crystals: one polymorph. Opaque middle layer: 0.1 μm scale size pores. Parallel outer layer: translucent crystalline layers.

The nature and composition of the outer layers of the cuticle of Acanthosentis oligospinus n.sp. (Acanthocephala) from the fish Macrones gulio

1969 ◽  
Vol 24 (12) ◽  
pp. 1629-1632 ◽  
Author(s):  
Sita Anantaraman
Keyword(s):  
Outer Layer ◽  
Outermost Layer ◽  
The One

The nature and composition of the outer layer of the cuticle of Acanthosentis oligospinus n.sp., were investigated. The outermost layer is formed of lipids and the one internal to it is constituted of lipoprotein. In staining reactions, in possession of resistant properties, and in the absence of chitin, these two layers recall the outer and inner epicuticle of arthropods.

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