Densely Distributed Research Articles

Dense distribution of macrophages in flexor aspects of the hand and foot of mid-term human fetuses

In the developing human musculoskeletal system, cell death with macrophage accumulation occurs in the thigh muscle and interdigital area. To comprehensively clarify the distribution of macrophages, we immunohistochemically examined 16 pairs of upper and lower extremities without the hip joint (left and right sides) obtained from 8 human fetuses at approximately 10-15 weeks of gestation. Rather than in muscles, CD68-positive macrophages were densely distributed in loose connective tissues of the flexor aspects of the extremities, especially in the wrist, hand and foot. In contrast, no or fewer macrophages were evident in the shoulder and the extensor aspects of the extremities. The macrophages were not concentrated at the enthesis of the tendon and ligament, but tended to be arranged along other connective tissue fibers. Deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling revealed apoptosis in the hand lumbricalis muscles, but not in the area of macrophage accumulation. Likewise, podoplanin-positive lymphatic vessels were not localized to areas of macrophage accumulation. Re-organization of the connective tissue along and around the flexor tendons of the hand and foot, such as development of the bursa or tendon sheath at 10-15 weeks, might require the phagocytotic function of macrophages, although details of the mechanism remain unknown.

Influence of γ′ and grain boundary carbide on tensile fracture behaviors of Nimonic 263

Tensile fracture behaviors of Nimonic 263 after three different heat treatments have been investigated. Standard heat treatment produces 10% γ′ coupled with precipitate free zones (PFZs), and M 23C 6 carbide densely distributed at grain boundaries (GBs). Alternative heat treatment causes dense distribution of GB carbides and precipitation of 1–3% γ′ with the absence of PFZs. Solution-treated sample has neither γ′ nor M 23C 6 carbide. Room temperature tensile tests indicate both standard and alternative heat-treated samples show intergranular fracture, but the elongation of the latter is two times larger than that of the former. The combined effect of GB carbides and intensive slip bands accounts for the intergranular fracture. The γ′ volume fraction affects elongation. Solution-treated sample displays transgranular fracture mode. Lack of restriction to dislocation mobility in grains interior and the weak interaction between GBs and dislocations are responsible for the transgranular fracture. The effect of PFZs on fracture mode may be negligible.

Nano-structure control in ODS martensitic steels by means of selecting titanium and oxygen contents

The effects of mechanical alloying (MA) conditions on oxygen contamination were investigated to establish the manufacturing technology of oxygen-controlled oxide dispersion strengthened (ODS) martensitic steel. High-temperature mechanical tests and microstructure observations were performed in oxygen-and-titanium-controlled steels in order to demonstrate high-temperature strength improvement using oxygen control. Oxygen content was drastically reduced by the purification of MA atmosphere, Ar gas. It was shown that the lower speed agitation at the beginning of MA was effective for the reduction of oxygen contamination because oxygen was mixed mainly at the beginning of mechanical alloying due to the imperfect replacement of Ar gas. Dense distribution of oxide particle and significant improvement in high-temperature strength were achieved by applying 99.9999 wt% Ar in MA atmosphere and reducing oxygen contents. It was revealed that the merely increasing Y 2O 3 and titanium addition cannot improve the high-temperature strength. The excess oxygen is an important parameter for making oxide particles finely and densely distributed as well as improving high-temperature strength.

Regional distribution of large landslide landforms in Japan

Distribution map of large landslide landforms (longer than 200m) on whole Japanese islands was compliled by using landslide maps (mainly 1: 50, 000 scale) and detection of 1: 25, 000 scale topographical maps. The landslide landforms are widely distributed on Japanese hills and mountains, especially in the back arc zone of Tohoku district, Shin-etsu, Hokuriku and Shikoku districts. Relationships between regional distribution of landslide landforms and geological and topographical features are analyzed by GIS (Geographical Information System) over the Japanese islands. Data on landslide landforms, geology, relief energy and slope gradi-ent were prepared with 2 x 2km mesh system. The number of meshes for statistical analyses is about 71, 000. Landslide landform exists in 43% of portion among these meshes. In 2602 meshes (3.7% of total meshes), landslide landforms cover more than 40% of each mesh area.The landslide landforms are densely distributed in the Neogene sedimentary rocks, Green Tuff and the Paleogene and Neogene coalfields. Relative high dense distribution of landslide landforms are observed in the mountaineous region with 400-800m of relief energy and 15°-30° of slope gradient. The landslide landforms are scarcely distributed in the areas with dispersion of altitude more than 120m or less than 30m.

Effective Propagation Constants and Attenuation Rates in Media of Densely Distributed Coated Dielectric Particles with Size Distributions

The effective propagation constants and attenuation rates in dense nontenuous media with coated dielectric particles governed by size distributions are studied. A coated particle consists of two layers with different materials. In a dense medium, particles do not scatter independently and the effects of correlated scattering have to be included. The correlated scattering can be taken into account by using the quasicrystalline approximation (QCA) or the quasicrystalline approximation with coherent potential (QCA-CP). The Lippmann-Schwinger equation for coated particles is solved analytically to calculate the T-matrix for both QCA and QCA-CP. We also consider the dense medium with particle sizes governed by size distribution. The pair distribution functions for particles of different sizes are computed by using the Percus-Yevick approximation. For small particles, closed form analytic expressions are obtained for the complex effective propagation constants. For moderate size particles, the complex effective...

Sympathetic innervation-mediating protein

The present study was performed to elucidate the mechanisms and molecular basis of specific innervation of the peripheral tissues. Chick sympathetic nerve fibers densely innervate expansor secundariorum muscle, but not skeletal muscle. When a sympathetic ganglion was cultured in collagen gel with muscle explants, the ganglion extended neurites towards two types of muscles to the same extent. Dissociated sympathetic ganglion neurons adhered firmly to the dish precoated with materials from expansor secundariorum but not to the dish precoated with those from skeletal muscle. Sympathetic nerve fibers were found densely distributed on the substrate from expansor secundariorum but not on the substrate from skeletal muscle. These results suggest that neuronal recognition mechanisms are involved in the process of selective sympathetic innervation of the expansor secundariorum muscle of the chick. The protein which caused the dense distribution of sympathetic fibers as the substrate has been purified from heart-cell-conditioned medium. The most purified fraction showed a single band with an apparent molecular weight of 370,000 daltons on SDS-PAGE under non-reducing and reducing conditions. The biological activity of the protein was over 100 times higher than that of laminin. Antiserum was raised against the factor in heart-cell-conditioned medium that induced the dense distribution of sympathetic fibers in culture. Addition of the antiserum to the culture medium inhibited the dense distribution of sympathetic fibers on the purified protein-substrate without affecting the general growth of the fibers. Subcutaneous injection of the antiserum into the chicks inhibited the regeneration of adrenergic fibers following 6-hydroxydopamine-induced axotomy in peripheral tissues (heart, spleen, kidney and blood vessel).(ABSTRACT TRUNCATED AT 250 WORDS)

モルモット鼻粘膜の神経支配

The autonomic and the peptidergic nerve fibers which control the blood flow and gland secretion in the nasal mucosa of the guinea pig were studied using histochemical and immunohistochemical techniques. There was a dense distribution of adrenergic nerve fibers (Adn) around the blood vessels, especially the vein, but a very sparse distribution in the glandular tissue. There was a dense distribution of cholinergic nerve fibers (Chn) both around the blood vessels and in the glandular tissue. The distribution of fibers containing vasoactive intestinal polypeptide (VIP) was dense in the glandular tissue but sparse around blood vessels and very sparse in the subepithelial layer. Fibers containing calcitonin gene-related peptide (CGRP) were densely distributed around blood vessels, glandular tissue and the subepithelial layer. A moderate number of CGRP containing fibers were observed in the intraepithelial layer. Fibers containing substance P (SP) and neurokinin A (NKA) were sparsely distributed around blood vessels, glandular tissue and the subepithelial layer. Radioimmunoassay for NKA and SP in the nasal mucosa revealed a greater content both of NKA and SP in the nasal concha than in the nasal septum. There was a greater content of NKA than SP in both the nasal septum and the nasal concha, with a higher SP/NKA ratio in the nasal concha than in the nasal septum.

Effective Propagation Constants in Media with Densely Distributed Dielectric Particles of Mutiple Sizes and permittivities

Effective Propagation Constants in Media with Densely Distributed Dielectric Particles of Mutiple Sizes and permittivities

Sensory innervation of the periodontal ligament in the incisor and molar of the monkey, Macaca fuscata. An immunohistochemical study for neurofilament protein and glia-specific S-100 protein.

Nervous elements in the periodontal ligament of the monkey, Macaca fuscata were investigated by means of immunohistochemistry for neurofilament protein (NFP) and S-100 protein. Thick nerve bundles with NFP-immunoreactivity entered the periodontal ligament through slits at the bottom of the alveolar socket, whereas thinner bundles, also NFP-immunoreactive, penetrated the ligament from the lateral wall of the alveolar socket. The NFP-immunopositive nerve fibers were densely distributed around the root apex in both incisors and molars. In the upper incisors, another dense distribution of NFP-positive nerves was found in the apical half of the lingual periodontal ligament and in the coronal half of the labial periodontal ligament. The periodontal nerve fibers in the incisors ramified in a dendritic fashion, terminating as free nerve endings within the periodontal ligament. Immunostaining for S-100 protein demonstrated the Schwann sheaths of nerves which showed the same distribution pattern as that of the NFP-immunopositive fibers in the periodontal ligament of the incisors. In molars, immunostaining for NFP and S-100 showed that nerves were numerous in the apical region of the periodontal ligament. However, NFP-immunopositive nerves were fewer than the S-100-positive nervous elements in the apical region in molars. This discrepancy suggests the presence of NFP-immunonegative nerves. Immunostaining for S-100 is thus useful for demonstration of neural elements in the periodontal ligament of molars. The S-100-immunoreactive neural elements in the periodontal ligament were more numerous in incisors than in molars. In addition to the free nerve endings, a small population of coiled nerve endings was observed in the periodontal ligament of molars. Most of the nerve fibers and cell bodies in the trigeminal ganglion showed NFP-immunoreactivity, whereas all in the mesencephalic nucleus of the trigeminal nerve were negative in NFP-reaction. This finding suggests that the periodontal ligament of molars receives a dual innervation from the trigeminal ganglion and mesencephalic nucleus.

Diffusion of a pulse in densely distributed scatterers

This paper presents a theoretical study on propagation and scattering characteristics of a short optical pulse in a dense distribution of scatterers. Examples include pulse diffusion in whole blood and in a dense distribution of particulate matter in the atmosphere and the ocean. The parabolic equation technique is applicable to the forward-scatter region where the angular spread is confined within narrow forward angles. When the angular spread becomes comparable to the order of unit steradian, there is as much backscattering as forward scattering and diffusion phenomena take place. We start with the integral and differential equations for the two-frequency mutual coherence function under the first-order smoothing approximation, and a general diffusion equation and boundary conditions are obtained. As examples, we present solutions for diffusion of a pulse from a point source and a plane wave incident on a slab of scatterers.