The blastomere pattern in echinoderms: cleavages one to four

Development ◽  
1977 ◽  
Vol 40 (1) ◽  
pp. 23-34
Author(s):  
John W. Prothero ◽  
Arnold Tamarin
Keyword(s):  
Longitudinal Study ◽  
Surface Area ◽  
Formal Model ◽  
Egg Volume ◽  
Cleavage Stage ◽  
Cell Stage ◽  
Subjective Impression ◽  
Position And Orientation ◽  
The Individual ◽  
Area And Volume

The results of a longitudinal study of the blastomere pattern in six embryos during the first four cleavages are reported. At each cleavage stage optical sections through an embryo, taken at vertical intervals of 5 or 10µm, were recorded on 35 mm film: digitization of the blastomere contours and computer analysis allow calculation of the center, radius, surface area and volume of each blastomere. The subjective impression of exquisite regularity seen in normal echinoderm blastulae acquires a quantitative dimension from the present study. For example, the individual angles formed by the various quartets of blastomeres depart from right angles by at most a few degrees. The egg volume was found to be conserved up to the fourth cleavage. At the 16-cell stage, unlike the earlier stages, the blastomere positions cannot be ascribed solely to the position and orientation of the respective cleavage planes. Finally, a few features of a formal model of these early cleavages are sketched.

scholarly journals Increasing demand for plasma membrane contributes to the energetic cost of early zebrafish embryogenesis

2019 ◽  
Author(s):  
Jonathan Rodenfels ◽  
Pablo Sartori ◽  
Stefan Golfier ◽  
Kartikeya Nagendra ◽  
Karla Neugebauer ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Surface Area ◽  
Heat Dissipation ◽  
Isothermal Calorimetry ◽  
Significant Proportion ◽  
Total Cell ◽  
Energetic Cost ◽  
Cleavage Stage ◽  
Energetic Costs ◽  
Cell Stage

AbstractHow do early embryos apportion the resources stored in the sperm and egg? Recently, we established isothermal calorimetry (ITC) to measure heat dissipation by living zebrafish embryos and to estimate the energetics of specific developmental events. During the reductive cleavage divisions, the rate of heat dissipation increases from ∼60 nJ·s−1 at the 2-cell stage to ∼90 nJ·s−1 at the 1024-cell stage. Here we ask, which cellular process(es) drive these increasing energetic costs? We present evidence that the cost is due to the increase in the total surface area of all of the cells of the embryo. First, embryo volume stays constant during the cleavage stage, indicating that the increase is not due to growth. Second, the heat increase is blocked by nocodazole, which inhibits DNA replication, mitosis and cell division; this implicates some aspect of cell proliferation contributing to these costs. Third, the heat increase scales with total cell surface area rather than total cell number. Finally, the calculated costs of maintaining and assembling plasma membranes and associated proteins probably accounts for a significant proportion of the heat increase. Thus, the cell’s membrane is likely to contribute significantly to the total energy budget of the embryo.Highlight summary for TOCRodenfels et al. measure the energetic costs of early zebrafish development, using calorimetry. Embryonic heat dissipation increases, but, more slowly than the number of cells during early cleavage stage development. Instead, the heat dissipation scales with the energetic cost associated with maintaining and producing new plasma membrane.

3D reconstruction and calculation of surface area and volume of bell pepper

2007 ◽  
Vol 3 (1) ◽  
pp. 89-113
Author(s):  
Zoltán Gillay ◽  
László Fenyvesi
Keyword(s):  
3D Reconstruction ◽  
Surface Area ◽  
Three Dimensional ◽  
Reference Method ◽  
Bell Pepper ◽  
Three Dimensional Model ◽  
Acceptable Error ◽  
Volume Calculation ◽  
Bell Peppers ◽  
Area And Volume

There was a method developed that generates the three-dimensional model of not axisymmetric produce, based on an arbitrary number of photos. The model can serve as a basis for calculating the surface area and the volume of produce. The efficiency of the reconstruction was tested on bell peppers and artificial shapes. In case of bell peppers 3-dimensional reconstruction was created from 4 images rotated in 45° angle intervals. The surface area and the volume were estimated on the basis of the reconstructed area. Furthermore, a new and simple reference method was devised to give precise results for the surface area of bell pepper. The results show that this 3D reconstruction-based surface area and volume calculation method is suitable to determine the surface area and volume of definite bell peppers with an acceptable error.

scholarly journals Impacts of stroke and cognitive impairment on activities of daily living in the Taiwan longitudinal study on aging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pi-Hsia Lee ◽  
Ting-Ting Yeh ◽  
Hsin-Yen Yen ◽  
Wan-Ling Hsu ◽  
Valeria Jia-Yi Chiu ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Longitudinal Study ◽  
Activities Of Daily Living ◽  
Daily Living ◽  
Skill Training ◽  
Community Dwelling ◽  
Combined Effects ◽  
Stroke Group ◽  
The Individual ◽  
Community Dwelling Older Adults

AbstractStroke and cognitive impairment are common in older population. They often occur together and their combined effects significantly increase disability in both basic (BADLs) and instrumental (IADLs) activities of daily living. We investigated the individual and combined impacts of stroke and cognitive impairment on BADLs and IADLs. A total of 3331 community-dwelling older adults were enrolled from the Taiwan longitudinal study on aging in 2011. Both BADLs and IADLs were analyzed. Combination of stroke and cognitive impairment increased severity of ADL disabilities, but similar prevalence, similar numbers of summed BADL and IADL tasks with disability, and similar levels of difficulty for each BADL and IADL task were found between the stroke group and cognitive impairment group. The former had more difficult in dressing while the latter had more difficult in using the telephone, transport, and managing finances. A hierarchy of ADLs was also observed in all groups. ADL skill training supplemented with cognitive and physical interventions should focus on secondary prevention of dementia and improve motor functional capacity to reduce loss of ADLs.

Theoretical and empirical scaling patterns and topological homology in bone trabeculae.

1998 ◽  
Vol 201 (4) ◽  
pp. 573-590
Author(s):  
S M Swartz ◽  
A Parker ◽  
C Huo
Keyword(s):  
Body Size ◽  
Surface Area ◽  
Cancellous Bone ◽  
Structural Design ◽  
Theoretical Models ◽  
Small Animals ◽  
Bone Trabeculae ◽  
Large Animals ◽  
Vertebrate Skeleton ◽  
Area And Volume

Trabecular or cancellous bone is a major element in the structural design of the vertebrate skeleton, but has received little attention from the perspective of the biology of scale. In this study, we investigated scaling patterns in the discrete bony elements of cancellous bone. First, we constructed two theoretical models, representative of the two extremes of realistic patterns of trabecular size changes associated with body size changes. In one, constant trabecular size (CTS), increases in cancellous bone volume with size arise through the addition of new elements of constant size. In the other model, constant trabecular geometry (CTG), the size of trabeculae increases isometrically. These models produce fundamentally different patterns of surface area and volume scaling. We then compared the models with empirical observations of scaling of trabecular dimensions in mammals ranging in mass from 4 to 40x10(6)g. Trabecular size showed little dependence on body size, approaching one of our theoretical models (CTS). This result suggests that some elements of trabecular architecture may be driven by the requirements of maintaining adequate surface area for calcium homeostasis. Additionally, we found two key consequences of this strongly negative allometry. First, the connectivity among trabecular elements is qualitatively different for small versus large animals; trabeculae connect primarily to cortical bone in very small animals and primarily to other trabeculae in larger animals. Second, small animals have very few trabeculae and, as a consequence, we were able to identify particular elements with a consistent position across individuals and, for some elements, across species. Finally, in order to infer the possible influence of gross differences in mechanical loading on trabecular size, we sampled trabecular dimensions extensively within Chiroptera and compared their trabecular dimensions with those of non-volant mammals. We found no systematic differences in trabecular size or scaling patterns related to locomotor mode.

Incorporation of Uridine in Cleavage Stage Eggs of the Sea Urchin Paracentrotus Lividus

1971 ◽  
Vol 26 (8) ◽  
pp. 816-821 ◽  
Author(s):  
Larry E. Bockstahler
Keyword(s):  
Ion Exchange ◽  
Sea Urchin ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Paracentrotus Lividus ◽  
Cleavage Stage ◽  
Early Cleavage ◽  
Cell Stage ◽  
Cleavage Stages ◽  
Layer Chromatography

Incorporation of uridine in cleavage stage eggs of the sea urchin Paracentrotus lividus was investigated. It was shown by ion exchange and thin layer chromatography that most of the uridine taken up during the 16-cell stage was converted into UTP with some incorporation into UDP and UMP. Conversion of uridine to these phosphorylated nucleosides occurred throughout early cleavage stages. A very small amount of uridine taken up by cleavage stage eggs is incorporated into RNA heterogeneous in size. This RNA was examined by polyacrylamide gel electrophoresis.

The individual and health sector costs of asthma: the first year of a longitudinal study in New South Wales

2005 ◽  
Vol 29 (5) ◽  
pp. 429-435 ◽  
Author(s):  
Patricia Kenny ◽  
Emily Lancsar ◽  
Jane Hall ◽  
Madeleine King ◽  
Meredyth Chaplin
Keyword(s):  
Longitudinal Study ◽  
New South ◽  
New South Wales ◽  
Health Sector ◽  
First Year ◽  
South Wales ◽  
The Individual

scholarly journals An Anatomically Placed Tibial Tunnel does not Completely Surround a Simulated PCL Reconstruction Graft in the Proximal Tibia

2022 ◽  
Author(s):  
Christopher Kim ◽  
Dustin Baker ◽  
Brian Albers ◽  
Scott G. Kaar
Keyword(s):  
Surface Area ◽  
Cruciate Ligament ◽  
Tibial Tunnel ◽  
Three Dimensional ◽  
Pcl Reconstruction ◽  
Posterior Cortex ◽  
Modeling Software ◽  
The Mean ◽  
Tibial Cortex ◽  
Area And Volume

Abstract Introduction It is hypothesized that anatomic tunnel placement will create tunnels with violation of the posterior cortex and subsequently an oblique aperture that is not circumferentially surrounded by bone. In this article, we aimed to characterize posterior cruciate ligament (PCL) tibial tunnel using a three-dimensional (3D) computed tomography (CT) model. Methods Ten normal knee CTs with the patella, femur, and fibula removed were used. Simulated 11 mm PCL tibial tunnels were created at 55, 50, 45, and 40 degrees. The morphology of the posterior proximal tibial exit was examined with 3D modeling software. The length of tunnel not circumferentially covered (cortex violation) was measured to where the tibial tunnel became circumferential. The surface area and volume of the cylinder both in contact with the tibial bone and that not in contact with the tibia were determined. The percentages of the stick-out length surface area and volume not in contact with bone were calculated. Results The mean stick-out length of uncovered graft at 55, 50, 45, and 40 degrees were 26.3, 20.5, 17.3, and 12.7 mm, respectively. The mean volume of exposed graft at 55, 50, 45, and 40 degrees were 840.8, 596.2, 425.6, and 302.9 mm3, respectively. The mean percent of volume of exposed graft at 55, 50, 45, and 40 degrees were 32, 29, 25, and 24%, respectively. The mean surface of exposed graft at 55, 50, 45, and 40 degrees were 372.2, 280.4, 208.8, and 153.3 mm2, respectively. The mean percent of surface area of exposed graft at 55, 50, 45, and 40 degrees were 40, 39, 34, and 34%, respectively. Conclusion Anatomic tibial tunnel creation using standard transtibial PCL reconstruction techniques consistently risks posterior tibial cortex violation and creation of an oblique aperture posteriorly. This risk is decreased with decreasing the angle of the tibial tunnel, though the posterior cortex is still compromised with angles as low as 40 degrees. With posterior cortex violation, a surgeon should be aware that a graft within the tunnel or socket posteriorly may not be fully in contact with bone. This is especially relevant with inlay and socket techniques.

scholarly journals Management of Severe Curvatures in Root Canal Treatment with the New Generation of Rotating Files Using a Safe and Predictable Protocol

2020 ◽  
Vol 14 (1) ◽  
pp. 421-425
Author(s):  
Alfredo Iandolo ◽  
Alessandra Amato ◽  
Stefano Martina ◽  
Dina Abdel latif ◽  
Giuseppe Pantaleo
Keyword(s):  
Surface Area ◽  
Root Canal ◽  
Root Canal Treatment ◽  
Complex Root ◽  
Root Canals ◽  
New Generation ◽  
Area And Volume ◽  
Clinical Cases

Objective: The aim of this work was to show the management of severe curvatures done with the new generation of rotating files through a safe and predictable protocol. Methods: Three clinical cases were described. A safe protocol was explained using the latest generation of rotating files for the shaping of the anatomy of complex root canals. All the cases presented 90°, 45° curvatures and/or double curvatures. Results: The instrumentation of canals increased their surface area and volume. All the cases with 90° and 45° curvatures were optimally shaped. Conclusion: With the help of rotating files in the martensitic alloy, it is possible to work safely, while avoiding the risk of file separation, even in root canals with severe curvatures, thus achieving success even in complex clinical cases.

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