Kinds Of Filaments Research Articles

Effects of Heat-Treatment on Tensile Behavior and Dimension Stability of 3D Printed Carbon Fiber Reinforced Composites.

This work investigated the effects of heat treatment on the tensile behavior of 3D-printed high modules carbon fiber-reinforced composites. The manufacturing of samples with different material combinations using polylactic acid (PLA) reinforced with 9% carbon fiber (PLACF), acrylonitrile butadiene styrene (ABS) reinforced with 9% carbon fiber (ABSCF) were made. This paper addresses the tensile behavior of different structured arrangements at different% of densities between two kinds of filaments. The comparison of the tensile behavior between heat treated and untreated samples. The results showed that heat treatment improves the tensile properties of samples by enhancing the bonding of filament layers and by reducing the porosity content. At all structure specifications, the rectilinear pattern gives higher strength of up to 33% compared with the Archimedean chords pattern. Moreover, there is a limited improvement in the tensile strength and modulus of elasticity values for the samples treated at low heat-treatment temperature. The suggested methodology to evaluate the tensile behavior of the pairs of materials selected is innovative and could be used to examine sandwich designs as an alternative to producing multi-material components using inexpensive materials.

HAVA-JETLİ TEKSTÜRE PBT İPLİKLERİN MEKANİK ÖZELLİKLERİNİN VE KARARSIZLIK DAVRANIŞLARININ İNCELENMESİ

Hava-jetli tekstüre işlemi, sentetik filamentlerin iplik içerisindeki düzenli yerleşimlerini mekanik yolla değiştirerek, bu filamentleri birbirine karışmış, hacimli, doğal ipliklere benzer bir yapıya dönüştürür. Bu teknikte, uygulanan aşırı beslemenin yardımıyla her çeşit filament, tekstüre jetinden uygulanan süpersonik hava akımının tesiriyle karıştırılabilir. Hava-jetli tekstüre işleminde jetten tekstüre olarak çıkan ipliğe, alım silindiri ile sevk silindiri arasında bir mekanik germe işlemi uygulanır. Mekanik germenin amacı, tam olarak ilmek oluşturamamış filamentlerin çözülmesi ve ilmek oluşturabilmiş filamentlerin daha iyi kilitlenerek ipliğin mekanik özelliklerini daha kararlı hale getirmektir. Hava-jetli tekstüre ipliklerin yapısında bulunan ilmeklerin bir kısmı uygulanan kuvvetlerin etkisiyle yok olabilir, iplik üzerinde kalan ilmeklerin miktarı bu ilmeklerin “kararlılığı” ile ilişkilidir. Poliesterler ana zincirlerinde ester bağları bulunduran sentetik liflerdir. Bu lifler olumlu performans özellikleri nedeniyle konvansiyonel ve endüstriyel alanlarda sıklıkla tercih edilmektedir. Farklı poliester çeşitleri arasında, polibütilen tereftalat (PBT) lifleri özellikle iyi toparlanma davranışının istendiği uygulamalarda tercih edilmektedir. Bu çalışmada hava-jetli tekstüre PBT ipliklerin mekanik özellikleri ve kararsızlık davranışları incelenmiştir. Yapılan ön denemelerde, mekanik germe oranının %6’nın üzerinde olduğu durumlarda iplik yapısında deformasyon gözlenmiştir. Bu nedenle bu çalışmada en yüksek %6 olacak şekilde 4 farklı mekanik germe (%0-2-4-6) ve 3 farklı aşırı besleme oranında (%20-40-60) hava-jetli tekstüre PBT iplikler üretilmiştir. Üretilen bu numunelerin, iplik numaraları, mekanik özellikleri ve elastik toparlanma davranışları incelenmiştir. Çekme ve elastik toparlanma deneylerinden elde edilen sonuçlar optik mikroskop deneyleriyle ilişkilendirilerek açıklanmıştır. Yapılan deneyler sonucunda, hava-jetli tekstüre PBT ipliklerde aşırı besleme oranındaki artışa bağlı olarak ilmekli yapıda bir artış gözlenmiştir. Bu durum, numunelerin iplik numarası ve kopma uzaması değerlerinde bir artışa, elastik toparlanma davranışlarında ise azalmaya neden olmuştur. En az ilmekli yapının gözlendiği %20 aşırı besleme ile üretilen numunelerde filamentler iplik eksenine olan paralelliklerini kısmen korumuştur. Dolayısıyla bu numuneler için hava-jetli tekstüre iplik yapısından ziyade filamentleri meydana getiren molekül zincirlerinin özellikleri ön plana çıkmış ve en iyi toparlanma bu iplik grubunda gözlenmiştir.

Effect of the morphology of polyesters filaments on their physical properties and dyeing performances

Nowadays, polyester fibers/filaments are undergoing innovations to keep their first place in the textile markets. This paper is devoted to study the physical and chemical properties of polyesters filaments with different geometries and their influence on dyeing performances. Four kinds of filaments were studied and compared: PET monofilaments with two different geometries, (A) circular and (B) cross-sectional shapes, (C) PTT monofilaments with tetra-channel shapes, and (D) bicomponent PET/PTT filaments. Different tools have been used to characterize studied filaments by determination their morphological behaviors, structures as well as their thermal and mechanical properties. Dyeing process of these polyester filaments was also investigated using a C.I Disperse Yellow 211 dye. The effects of dyeing parameters (temperature, time and carrier concentration) on dyeing performances (color strength and CIELab coordinates) were then studied and optimized used Box–Behnken experimental design. The comparing results showed that the filaments (D) give an excellent dyestuff affinity. Finally, samples dyed under optimum conditions showed that those knitted using filaments (D) present the highest strength color (25.3), followed by filaments (B) (21.4), filaments (C) (19.9) and filaments (A) (19.4).

Graphene Enhanced Secondary Ion Mass Spectrometry (GESIMS)

The following invention - Graphene Enhanced Secondary Ion Mass Spectrometry - (pending European patent application no. EP 16461554.4) is related to a method of analysing a solid substrate by means of Secondary Ion Mass Spectrometry (SIMS). It comprises the steps of providing a graphene layer over the substrate surface and analysing ejected secondary anions through mass spectrometry analysis. The graphene layer acts as a kind of filament that emits a lot of secondary electrons during the experiment which significantly increases the negative ionization probability and thus the intensity of the SIMS signal can be more than two orders of magnitude higher than that of a similar sample without graphene. The method is particularly useful for the analysis of surfaces, 2D materials and ultra-thin films. The intensity of dopants and contamination signals can be enhanced up to 35 times, which approaches the detection limit of ~1015atoms/cm3, otherwise unreachable in a standard static SIMS analysis.

Laser filamentation in air via Mathieu modulation: ranging from trajectory-predesigned curved filament to quasi-soliton and ring light bullet.

We propose theoretically various kinds of filaments via the Mathieu modulation. Our results indicate curved filaments, in-phase and out-of-phase quasi-solitons and nonlinear light bullets can be formed successfully in air. Through calculated initial Mathieu accelerating beam (MAB), curved filament is able to propagate along a predesigned elliptical trajectory. By transforming the MAB into an axial symmetrical structure with in-phase and out-of-phase modulations, we obtain two kinds of quasi-solitons in air, respectively. The latter case can even propagate in a breathing fashion. With a ring structure of MAB, we successfully form a light bullet in air that generates a chain of intensity peaks over extended distances. These unique filaments can offer significant advantages for numerous applications, such as micro engineering of materials, THz radiation generation and attosecond physics.

Effect of covering filaments on the compression performance and failure mechanism of unidirectional fiber‐reinforced plastic

The effects of covering ultra‐high molecular weight polyethylene (UHMWPE) fibers with different types and spacings of filaments on the longitudinal compression properties of unidirectional UHMWPE fiber‐reinforced epoxy resin samples were investigated. UHMWPE fiber bundles covered with fiber filaments were prepared using a custom winding machine, and composites were subsequently fabricated by vacuum‐assisted resin transfer molding. Covering filament spacing was controlled by the warp speed. Compression testing of the resulting samples was performed and the fracture surfaces were examined by an optical microscope. The results showed that the compression strength and modulus of the unidirectional composites reinforced with filament‐covered bundles depended strongly on the compressive failure mechanism, which was decided by the type and spacing of the covering filament. Four kinds of filaments have positive effect for compressive properties of composites, for the basalt filament, the effect for improving compressive strength is best, the improving percentage is 18.4%. For the UHMWP and PBO filament‐covered UFRPs displayed considerable increases of compressive modulus, with improvements of about 36% and 45%. POLYM. COMPOS., 39:247–253, 2018. © 2016 Society of Plastics Engineers

Evidencias petrográficas de estructuras de origen algal/bacteriano en carbonatos de la Formación Agua Nueva (Cenomaniano/Turoniano: Cretácico Superior) en Xilitla, S.L.P. México central

This paper documents and describes fossil microbial structures inferred to be of algal/bacterial origin in the Upper Cretaceous Agua Nueva Formation in the Xilitla area (San Luis Potosi, Mexico), located in the southern part of the Tampico-Misantla basin. The sequence consists of alternating decimeter-thick beds of limestone with occasional brown shale and green bentonite layers. The limeston also include intermittent beds of black chert. The sedimentary succession shows two calcareous facies: 1) dark laminated limestones containing fossil remains of holosteans, teleosteans and shark teeth, as well as lenticular layers of sedimentary pyrite, and high content of organic matter (Corg1 ‒ 8 wt%); and 2) gray, non-laminated, bioturbated limestones with low content of organic matter (Corg < 1.0 wt%). Petrographic and scanning electron microscope analyses of the laminated limestone reveal a micritic matrix with sub-parallel wavy lamination, continuous and discontinuous folded laminae with shreds of organic matter, as well as different kinds of filaments, coated grains and planktonic foraminifera. On the other hand, the non-laminated, bioturbated limestone comprises infrequent filaments and pyrite. Both textures and biomorphic structures are very similar to those previously described for ancient and recent sediments representative of microbial origin. Furthermore, the occurrence of filaments embedded in the organic-matter-rich laminae suggests in situ production related to benthic microbial activity. Concurrence of lamination due to the absence of bioturbation, pervasive framboidal pyrite, and the high concentration of organic matter in the laminated limestones are consistent with persistent dysoxic/anoxic conditions, whereas the bioturbated limestones might represent recurrent relatively well-oxygenated episodes. The presence of the planktonic foraminifera Rotalipora cushmani concomitant with Inoceramus labiatus indicates a time interval from the Late Cenomanian to the Earliest Turonian for the Agua Nueva Formation at Xilitla, thus indicating that this interval of intermittent severe oxygen deficient conditions is coeval with the global Oceanic Anoxic Event 2 (OAE-2).

Universal Relation between Reset Current and Initial Resistance in Forming-Free Resistance Random Access Memory

Recently, the idea that the resistance change phenomenon is caused by oxidation/reduction of the filament formed in the transition metal oxide has been widely accepted. However, it is difficult to cause the forming equally for every cell in a high-density memory cell array. Therefore, the existence of the forming is high barrier for resistive random access memory (ReRAM) to be put into practical use. In this paper, the initial resistance dependence of the reset current and the distribution of the forming and set voltages were investigated for the forming-free ReRAM cells, which start with the reset process. As a result, it was clarified that the reset current is proportional to the reciprocal of initial resistance independently of the film thickness and the film formation temperature. In addition, it was suggested that there are two kinds of filaments in the forming-free ReRAM. One is the filament which is completely restored by the first reset process. The other continues to operate even after the first reset.

Alteration of nuclear matrix-intermediate filament system and differential expression of nuclear matrix proteins during human hepatocarcinoma cell differentiation

To investigate the association between the configurational and compositional changes of nuclear matrix and the differentiation of carcinoma cells. Cells cultured with or without 5 x 10(-3) mmol/L of hexamethylene bisacetamide (HMBA) on Nickel grids were treated by selective extraction and prepared for whole mount observation under electron microscopy. The samples were examined under transmission electron microscope. Nuclear matrix proteins were selectively extracted and subjected to subcellular proteomics study. The protein expression patterns were analyzed by PDQuest software. Spots of differentially expressed nuclear matrix proteins were excised and subjected to in situ digestion with trypsin. The peptides were analyzed by matrix-assisted laser-desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS). Data were submitted for database searching using Mascot tool (www.matrixscience.com). The nuclear matrix (NM) and intermediate filament (IF) in SMMC-7721 hepatocarcinoma cells were found relatively sparse and arranged irregularly. The nuclear lamina was non-uniform, and two kinds of filaments were not tightly connected. After induction for differentiation by HMBA, the NM-IF filaments were concentrated and distributed uniformly. The heterogeneous population of filaments, including highly branched ultrathin filaments could also be seen in the regular meshwork. The connection between the two kinds of filaments and the relatively thin, condensed and sharply demarcated lamina composed of intermediate-sized filaments was relatively fastened. Meanwhile, 21 NM proteins changed remarkably during SMMC-7721 cell differentiation. Four proteins, i.e. mutant Pyst1, hypothetical protein, nucleophosmin 1, and LBP were downregulated, whereas four other proteins, eIF6, p44 subunit, beta-tubulin, and SIN3B were upregulated with the last one, SR2/ASF found only in the differentiated SMMC-7721 cells. The induced differentiation of SMMC-7721 cells by HMBA is accompanied by the configurational changes of nuclear matrix-intermediate filament (NM-IF) system and the compositional changes of nuclear matrix protein expression. These changes may be important morphological or functional indications of the cancer cell reversion.

Fe(NO3)3.9H2O and Fe3(CO)12 as catalyst precursors for the elaboration of VGCF: SEM and TEM study—improvement of the process

Using Grafoil® (Union Carbide) as a substrate, we compare the effect of two catalyst precursors, namely Fe(NO3)3.9H2O and Fe3(CO)12 on the elaboration of carbon fibres. For each precursor, the mass of deposited carbon, of carbon fibres, and especially the fibre length was found to be strongly dependent on the concentration of catalyst precursor over the support. Moreover the methane percentage in the gas mixture plays an important role in the mass of gathered fibres. To observe the modification of the substrate morphology with increasing temperature, several experiments were interrupted at different temperatures within the 900–1110°C range. The results obtained from SEM and TEM revealed that at least two kinds of filaments had grown on the substrate, and that only one of them could give rise to carbon fibres. Precursor filaments were evidenced as having a nanotubular structure and were sometimes agglomerated in bundles. The different stages of fibre growth are also discussed.

Effect of retinoic acid on the changes of nuclear matrix in termediate filament system in gastric carcinoma cells.

AIM:To explore the relationship between the configuration changes of the nuclear matrix intermediate filament system in cancer cell induced by retinoic acid and the malignant phenotypic reversion of cancer cells.METHODS:The human gastric adenocarcinoma cell line MGc80-3 cells were induced with 10(-6) mol/L retinoic acid and subcultured at cover slip strip and gold grids. The cells were treated by selective extraction method and prepared for whole mount electron microscopy observation. The samples were examined respectively with scanning and transmission electron microscope.RESULTS:The nuclear matrix filaments and intermediate filaments in MGc80-3 cells were relatively few and scattered, not well-distributed and arranged irregularly. The nuclear lamina was ununiformly thick and compact, connected to the nuclear matrix filaments and intermediate filaments relaxedly. However, the two kinds of filaments were abundant and well-distributed, different in slender and thick form and interweaved into a regular network in the cells induced by 10(-6)mol/L RA. The nuclear matrix filaments and inter-mediate filaments were connected closely by the thin and compact fiber-like lamina, and interlaced into a regular network throughout the whole cell region.CONCLUSION:The NM-IF system in MGc80-3 cells had undergone a restorational change similar to those of normal cells after RA inducement. This alternation is an important mor-phological and functional expression to the malignant phenotypic reversion of cancer cells.

Paired helical filaments in corticobasal degeneration: the fine fibrillary structure with NanoVan

Paired helical filaments (PHF) composed of hyperphosphorylated tau proteins are characteristic findings in neurodegenerative disorders, including Alzheimer's disease (AD) and corticobasal degeneration (CBD). The filaments in CBD differ from those in AD by a reduced number of tau isoforms and less stable ultrastructure. To further compare the ultrastructure of both filaments, we employed a novel staining reagent, NanoVan, as well as aurothioglucose and uranyl acetate. With commonly used uranyl acetate, both kinds of filaments appeared as twisted ribbons 15–20-nm and 21–23-nm wide, respectively, without significant internal substructure. With application of aurothioglucose, only few structural details were apparent. With NanoVan, AD filaments showed similar structure to that with uranyl acetate but CBD filaments displayed a highly heterogeneous appearance consistent with the dissociation of the 20–25-nm-wide filaments along two longitudinal axes. This was evident by the presence of thinner, 12–13-nm-wide filaments and filaments that splayed into two 20–25-nm-wide components at one or both ends. Moreover, detection of a prominent, 7–8-nm-wide axial region distinguished up to four protofilaments per one filament. Each protofilament appeared to contain two 3–5-nm-wide fibrils separated by an approximately 1-nm-wide axial region. The results suggest that 3–5-nm fibrils are the smallest structural subunits of filaments in CBD and that NanoVan may be an unique reagent in detecting eight-fibril organization in these less stable filaments.

Size of the export channel in the flagellar filament of Salmonella typhimurium

The size of the putative export channel in the bacterial flagellar filament appears small (25 Å) in studies done by electron microscopy but large (60 Å) in studies done by X-ray diffraction. We have undertaken additional studies by electron microscopy to examine some of the possible causes of the difference. A comparison of three-dimensional image reconstructions of native and reconstituted filaments rules out the presence or absence of flagellin monomers in the export channel as the source of the variation in apparent channel size. The channel seen in reconstructions from both kinds of filaments is 25 Å in diameter. The difference in the previous studies is more probably a result of artifacts introduced in either the X-ray or the electron microscopical methodology. Comparisons of three-dimensional reconstructions from images of filaments embedded in various stains (anionic, cationic and neutral) and in ice, taken at a range of defocuses, rule out the two most likely sources of artifact in electron microscopy ( i.e., staining artifacts and defocus phase contrast). Based on these studies we suggest that the channel seen in the image reconstructions is free of exported flagellin monomers, that its true diameter is about 25 Å, and, therefore, that the flagellin monomer must be unfolded to pass along it.

Scanning Electron Microscopy of the Epidermal Lamina Densa in Normal Human Skin

The lamina densa of normal human epidermis was exposed by treatment with 1 M sodium chloride and was examined by high-power scanning electron microscopy before and after trypsinization. Localization of type IV collagen in the lamina densa was also studied by transmission and scanning immunoelectron microscopy. Before trypsinization, the surface of the lamina densa consisted of microridges and microvalleys. The microridges varied in height and were connected with each other. They were arranged in a concentric fashion around the tips of the dermal microprojections. At a higher magnification, the surface of the lamina densa was composed of densely packed cobblestone-like structures approximately 7-15 nm in size, between which were interspaces 4-11 nm wide. These structures expressed type IV collagen. After trypsinization, the lamina densa was found to be composed of microfilaments approximately 10 nm thick showing beaded appearances. These microfilaments exhibited the same cobblestone-like structures as the lamina densa surface. Observation of the torn lamina densa demonstrated anchoring fibrils and oxytalan fibers that were attached to the lamina densa itself. Another kind of filament about 7 nm thick linked the anchoring fibrils and the oxytalan fibers. Beneath the lamina densa was a network of fibers about 40-50 nm thick, which was composed of collagen fibers and possibly also elaunin fibers. In conclusion, this study revealed the detailed surface ultrastructure of the epidermal lamina densa and its underlying filamentous elements.

Ｃｈｅｍｏｎｕｃｌｅｏｌｙｓｉｓにおける細胞外マトリックスの微細構造

We investgated the changes of proteoglycan (PG) structure in chemonucleolysis using an electron microscope. Dehydration was used before embedding N-N-dimethylformamide (DMF) but not ethanol. Two Kinds of filaments were identified in the extracellular matrix of a normal rabbit's intervertebral disc except for collagen fibers. The small filaments had disappeared in the nucleus pulposus three hours after injecting chymopapain. The large filaments had disappeared and the small ones changed in the nucleus pulposus three hours after injecting hyaluronidase. As chymopapain is a cysteine protease, it affects the protein component of PG. Hyaluronidase affects a hyaluronic acid and glycosaminoglycans of the PG monomer. We assumed that the small filament is a PG monomer and the large one is a hyaluronic acid. Chymopapain digests proteins of the PG monomer, so the PG looses water and its network of collagen fibers.

Cytoskeletal architecture of neuromuscular junction: Localization of vinculin

Cytoskeletons underneath the postsynaptic membrane of neuromuscular junctions were studied by using a quick-freeze deep-etch method and immunoelectron microscopy of ultrathin frozen sections. In a quick-freeze deep-etched replica of fresh, unfixed muscles, 8.9 +/- 1.5-nm particles were present on the true postsynaptic membrane surface. Underneath this receptor-rich postsynaptic membrane, networks of fine filaments were observed. These cytoskeletal networks were more clearly observed in extracted samples. In these samples, diameters of the filaments which formed networks were measured. In the platinum replica, three kinds of filament were recognized--12 nm, 9 nm, and 7 nm in diameter. The 12-nm filament seemed to correspond to the intermediate filament. The other two filaments formed meshworks between intermediate filaments and plasma membrane. In ultrathin frozen sections vinculin label was localized just beneath the plasma membrane. Thirty-six percent of the label was within 18 nm from the cytoplasmic side of the plasma membrane and 50% was within 30 nm. Taking the size of the vinculin molecule into account, it was concluded that vinculin is localized just beneath the plasma membrane and might play some role in anchoring filaments which formed meshworks underneath the plasma membrane.

Simulation of the behavior of supported metal catalysts in real reaction atmospheres by means of model catalysts

Model catalysts formed of small crystallites of Ni, Co, or Fe supported on thin, electron transparent films of nonporous alumina were heated in chemical atmospheres having compositions in the range encountered in the steam-reforming reaction. Electron microscopy and electron diffraction were used to investigate the physical and chemical changes that occurred. For a better understanding of the phenomena involved, the effect of the mixture is compared to the effects caused by the individual components and by their combinations. It is shown that, depending upon the nature of the catalyst as well as upon the composition of the mixture, sintering or/and coking can occur much more rapidly in mixtures than in single-component atmospheres. This suggests that a cooperative action of the reaction components is the cause of the early deactivation of the steam-reforming catalysts. Various phenomena such as carbon deposition (as films or patches on the surface of the catalyst and on the substrate or as filaments), deformation of the crystallites, severe sintering, and permanent loss of metal to the gas stream were observed. Explanations are provided for the behavior of the Ni Al 2O 3 , Co Al 2O 3 , and Fe Al 2O 3 catalysts, in various atmospheres, by considering the competition between carbon deposition and its gasification, as well as the strength of the interactions between crystallites and substrate. Two kinds of filaments were observed: carbonaceous filaments and metal oxide filaments which probably contain some carbon. A thermodynamic condition for the formation of filamentous carbon is suggested. If the sum of the interfacial free energies between carbon and crystallite, and carbon and substrate is smaller than that between crystallite and substrate, then carbon could penetrate between crystallites and substrate and filaments would be generated. Indeed, carbonaceous filaments were identified only when the catalyst particles were present as metals. In such cases, the interfacial free energy between the metal crystallite and alumina is much greater than that between the oxidized metal and alumina and the above thermodynamic condition is more likely to be satisfied. Permanent loss of active metal to the gas stream occurred, either because of the disintegration of the crystallites caused by carbon precipitation inside the particles, and/or possibly because of the formation of volatile Carbonyls.

Active movement of synthetic myosin filaments observed by dark-field light microscopy.

Long bipolar filaments synthesized from rabbit skeletal myosin have been visualized directly under a dark-field light microscope. It was also possible to observe movements of single myosin filaments in the presence of F-actin, which was invisible. When the two kinds of filaments were mixed (final concentrations: 17 micrograms/ml myosin and 0.6 mg/ml actin) in a medium containing 0.13 M KCl, 3 mM MgCl2, and 1 mM ATP, myosin filaments did not aggregate for a long period of time but were distributed separately in the field of microscope. Under these conditions, myosin filaments intermittently moved along their length in a bidirectional manner with a maximum instantaneous velocity of 5 micron/s. Individual filaments alternated, at random, between motile and nonmotile periods of time, with the motile fraction of filaments at any moment being roughly 10%. The in vitro movement of myosin filaments may be caused by their active sliding relative to F-actin in the background.

Ultrastructural characteristics of capillaries entering and leaving the stria vascularis.

Capillaries entering and leaving the stria vascularis were surrounded by layers of basal cells and fibrocytes. The entering capillaries were surrounded by one or two thin basal cells, while the leaving capillaries were surrounded by four or five thicker and interdigitated basal cell layers. Moreover, the layers surrounding the leaving capillaries persisted further into the spiral ligament. Two kinds of filaments were observed in the basal cells, one thin and the other thick. Capillaries were observed to leak horseradish peroxidase before they entered and after they left the stria vascularis. Although the reaction product of horseradish peroxidase was observed in all perivascular spaces of leaving capillaries, very little or no reaction product was observed around some entering capillaries. It is speculated that the layers of basal cells and fibrocytes around entering and leaving capillaries control the vascularis, although the layers around leaving capillaries may be more contractile than those around entering capillaries.

Ultrastructural Characteristics of Capillaries Entering and Leaving the Stria Vascularis

Capillaries entering and leaving the stria vascularis were surrounded by layers of basal cells and fibrocytes. The entering capillaries were surrounded by one or two thin basal cells, while the leaving capillaries were surrounded by four or five thicker and interdigitated basal cell layers. Moreover, the layers surrounding the leaving capillaries persisted further into the spiral ligament. Two kinds of filaments were observed in the basal cells, one thin and the other thick. Capillaries were observed to leak horseradish peroxidase before they entered and after they left the stria vascularis. Although the reaction product of horseradish peroxidase was observed in all perivascular spaces of leaving capillaries, very little or no reaction product was observed around some entering capillaries. It is speculated that the layers of basal cells and fibrocytes around entering and leaving capillaries control the vascularis, although the layers around leaving capillaries may be more contractile than those around entering capillaries.