scholarly journals Regeneration in the Gorgonian Plexura Flexuosa (Cnidaria, Octocorallia)

1977 ◽  
Vol 47 (1) ◽  
pp. 98-108 ◽  
Author(s):  
Fábio Lang da Silveira ◽  
Tom van’t Hof

Regenerative capability of Plexaura flexuosa is investigated in experiments which simulate the injuries caused by predation of the ovulid snail Cyphoma gibbosum: partial or total removal of the coenenchyme from the axial skeleton.

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Matthew Q. Lucas ◽  
Luis R. Rodríguez ◽  
Duane J. Sanabria ◽  
Ernesto Weil

This study evaluated the natural prey preferences and spatial variability of predation pressure (PP = proportion of colonies with snails and/or clear predation signs) by the gastropod Cyphoma gibbosum on octocoral communities off the La Parguera Natural Reserve, Puerto Rico. All octocoral colonies were checked for presence of C. gibbosum and/or clear predation signs in four permanent band-transects (2×10 m), along three depth intervals (0–5, 7–12, >15 m deep) in each of six reefs along an inshore offshore gradient. Results indicate that C. gibbosum preys on at least 16 species, six of which (Briareum asbestinum, Gorgonia ventalina, Pseudoterogorgia americana, P. acerosa, Plexaura flexuosa, and Pseudoplexaura porosa) consistently showed significantly higher (K-W, P<0.05) (17–37%) PP compared to all other species. Plexaura flexuosa, P. americana, and P. porosa had significantly higher PP (11–38%) among inner and mid-shelf reefs, and G. ventalina had higher PP in shelf-edge reefs (16–20%). A combination of differential spatial distributions and octocoral species abundances seems to explain the observed patterns of predation by C. gibbosum. Prey preference and higher abundances of 3-dimensional octocorals providing increased refuge or microhabitats utilized for mating or egg-deposition could be driving the spatial distribution of C. gibbosum and the observed differential predation pressure.


Author(s):  
R. C. Moretz ◽  
D. F. Parsons

Short lifetime or total absence of electron diffraction of ordered biological specimens is an indication that the specimen undergoes extensive molecular structural damage in the electron microscope. The specimen damage is due to the interaction of the electron beam (40-100 kV) with the specimen and the total removal of water from the structure by vacuum drying. The lower percentage of inelastic scattering at 1 MeV makes it possible to minimize the beam damage to the specimen. The elimination of vacuum drying by modification of the electron microscope is expected to allow more meaningful investigations of biological specimens at 100 kV until 1 MeV electron microscopes become more readily available. One modification, two-film microchambers, has been explored for both biological and non-biological studies.


1993 ◽  
Vol 06 (02) ◽  
pp. 100-104 ◽  
Author(s):  
D. M. Pickles ◽  
C. R. Bellenger

SummaryTotal removal of a knee joint meniscus is followed by osteoarthritis in many mammalian species. Altered load-bearing has been observed in the human knee following meniscectomy but less is known about biochemical effects of meniscectomy in other species. Using pressure sensitive paper in sheep knee (stifle) joints it was found that, for comparable loads, the load-bearing area on the medial tibial condyle was significantly reduced following medial meniscectomy. Also, for loads of between 50 N and 500 N applied to the whole joint, the slope of the regression of contact area against load was much smaller. Following medial meniscectomy, the ability to increase contact area as load increased was markedly reduced.The load bearing area on the medial tibial condyle was reduced following meniscectomy.


2016 ◽  
Author(s):  
Barbara Tymczyna ◽  
Marcin Tatara ◽  
Monika Tymczyna-Sobotka ◽  
Witold Krupski ◽  
Anna Szabelska

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 701 ◽  
Author(s):  
Lei Guo ◽  
Xiaochun Wen ◽  
Qipeng Bao ◽  
Zhancheng Guo

An investigation was made on the super-gravity aided rheorefining process of recycled 7075 aluminum alloy in order to remove tramp elements. The separation temperatures in this study were selected as 609 °C, 617 °C and 625 °C. And the gravity coefficients were set as 400 G, 700 G, 1000 G. The finely distributed impurity inclusions will aggregate to the grain boundaries of Al-enriched phase during heat treatment. In the field of super-gravity, the liquid phase composed of tramp elements Zn, Cu, Mg et al. will flow through the gaps between solid Al-enriched grains and form into filtrate. Both the weight of filtrate and removal ratio of tramp element improved with the increase of gravity coefficient. The total removal ratio of tramp element decreased with the fall of temperature due to the flowability deterioration of liquid phase. The time for effective separation of liquid/solid phases with super-gravity can be restricted within 1 min.


2021 ◽  
pp. 021849232110139
Author(s):  
Fumio Yamana ◽  
Keitaro Domae ◽  
Yukitoshi Shirakawa ◽  
Toshiki Takahashi ◽  
Hiroyuki Hao

Cardiac calcified amorphous tumors are rare non-neoplastic intracavitary masses with unknown cause. A 60-year-old man presented with sustained ventricular tachycardia. Transthoracic echocardiography and contrast-enhanced angio-computed tomography demonstrated an expanding 73 × 40 mm sized calcified mass in the left ventricle. He underwent successful total removal of the mass and cryo-ablation at the normal myocardial border. Histopathological examination confirmed a diagnosis of cardiac calcified amorphous tumors. The postoperative course was uneventful, without ventricular tachycardia recurrence. To our knowledge, this is the first reported case of confirmed cardiac calcified amorphous tumors causing ventricular tachycardia and treated by surgical resection combined with cryo-ablation.


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