scholarly journals Variability of the Surface Area of the V1, V2, and V3 Maps in a Large Sample of Human Observers

2021 ◽  
Author(s):  
Noah C Benson ◽  
Jennifer M. D. Yoon ◽  
Dylan Forenzo ◽  
Kendrick N. Kay ◽  
Stephen A Engel ◽  
...  
Keyword(s):  
Surface Area ◽  
Monozygotic Twins ◽  
Individual Variability ◽  
Visual Area ◽  
Surface Areas ◽  
Genes And Environment ◽  
Human Connectome Project ◽  
Intraclass Correlations ◽  
Cortical Magnification ◽  
Genetically Determined

How variable is the functionally-defined structure of early visual areas in human cortex and how much variability is shared between twins? Here we quantify individual differences in the best understood functionally-defined regions of cortex: V1, V2, V3. The Human Connectome Project includes retinotopic measurements from 181 subjects, most of whom are twins. We trained four "anatomists" to manually define V1-V3 using retinotopic features. These definitions were more accurate than automated anatomical templates and showed that surface areas for these maps varied more than three-fold across individuals. The cortical magnification function also differed substantially among individuals: the relative amount of cortex devoted to central vision varied by more than a factor of 2. Whereas our twin sample sizes were too small to make precise heritability estimates (50 monozygotic pairs, 34 dizygotic), they nonetheless reveal high correlations, consistent with strong effects of the combination of shared genes and environment on visual area size. In V1, intraclass correlations of surface area between twin pairs were 84% and 68% for monozygotic and dizygotic pairs, respectively. The correlations were also high for V2 (81%, 73%) and V3 (75%, 43%). A trend for higher monozygotic than dizygotic size correlations, as well as greater similarity in map properties amongst monozygotic twins, suggest that visual area size and topography are partly genetically determined. Collectively, these results comprise the most accurate account of individual variability in visual area structure to date, and provide a robust population benchmark against which new individuals and developmental and clinical populations can be compared.

Genetic and Environmental Influences on Adiponectin, Leptin, and BMI Among Adolescents in Taiwan: A Multivariate Twin/Sibling Analysis

2008 ◽  
Vol 11 (5) ◽  
pp. 495-504 ◽  
Author(s):  
Pi-Hua Liu ◽  
Yi-Der Jiang ◽  
Wei J. Chen ◽  
Ching-Chung Chang ◽  
Tso-Ching Lee ◽  
...  
Keyword(s):  
Structural Equation ◽  
Monozygotic Twins ◽  
Equation Modeling ◽  
Shared Environment ◽  
Latent Factor ◽  
Sibling Pairs ◽  
Relative Contribution ◽  
Genes And Environment ◽  
Intraclass Correlations ◽  
Mz Twins

AbstractCirculating levels of leptin and adiponectin are closely associated with obesity. However, it is not known whether there are common shared genes or environment exerting influences on the levels of leptin, adiponectin, and BMI. We aimed to assess the relative contribution of genes and environment to adiponectin, leptin, and BMI individually as well as simultaneously to the three measures. Our subjects included a total of 228 twin/sibling pairs aged 12 to 18 (130 monozygotic twins, 68 dizygotic twins and 30 sibling pairs) were recruited from the middle schools. Multivariate analyses were applied to twin/sibling data using structural equation modeling. The results showed that intraclass correlations for adiponectin, leptin and BMI were higher in the MZ twins than those in the DZ/SP group. The relative contribution of genes to adiponectin (39%) was comparable to those of shared environment (40%). In contrast, leptin and BMI were influenced mostly by genes (74% and 89%, respectively). The multivariate genetic analyses showed that a latent factor underlying the three measures was identified, with BMI being equivalent to this latent factor. The BMI-dependent genetic factor explains only 15% and 34% of variation of adiponectin and leptin, respectively. These data indicate a differential contribution of genetic factors for the variation of adiponectin, leptin and BMI. More importantly, only a small portion of the genetic influences on adiponectin and leptin was attributed to BMI. Our findings provided more insight into the complex regulation of adiponectin and leptin in obesity.

scholarly journals Innate Organization of the Human Brain

2021 ◽  
Author(s):  
M. Fiona Molloy ◽  
Zeynep M. Saygin
Keyword(s):  
Individual Variability ◽  
Adult Brain ◽  
Brain Organization ◽  
Attention Networks ◽  
Functional Brain ◽  
Human Connectome Project ◽  
Differential Gene ◽  
Functional Brain Organization ◽  
High Level ◽  
Genetically Determined

The adult brain is organized into distinct functional networks, forming the basis of information processing and determining individual differences in behavior. Is this network organization genetically determined and present at birth? Here, we use unsupervised learning to uncover intrinsic functional brain organization using resting-state connectivity from a large cohort of neonates (Developing Human Connectome Project). We identified a set of symmetric, hierarchical, and replicable networks: sensorimotor, visual, default mode, ventral attention, and high-level vision. We also quantified neonate individual variability, finding low variability for sensorimotor, but high for ventral attention networks. These neonate networks resembled adult networks (Yeo et al., 2011), but frontoparietal and limbic networks found in adults were indiscernible in neonates. Finally, differential gene expression provided a potential explanation for the emergence of these distinct networks. Our results reveal the basic proto-organization of cortex at birth, but indicate a role for maturation and experience in developing adult-like functional brain organization.

Cell morphology, volume, and surface area determinations from multilevel contouring within HVEM micrographs of serial sections and whole-cell mounts

1987 ◽  
Vol 45 ◽  
pp. 588-589
Author(s):  
M. Marko ◽  
A. Leith ◽  
D. Parsons
Keyword(s):  
Surface Area ◽  
Electron Micrographs ◽  
Cell Morphology ◽  
Individual Variation ◽  
Serial Section ◽  
Stereo Pair ◽  
Complex Structures ◽  
Serial Sections ◽  
Surface Areas ◽  
Computer Based

The use of serial sections and computer-based 3-D reconstruction techniques affords an opportunity not only to visualize the shape and distribution of the structures being studied, but also to determine their volumes and surface areas. Up until now, this has been done using serial ultrathin sections.The serial-section approach differs from the stereo logical methods of Weibel in that it is based on the Information from a set of single, complete cells (or organelles) rather than on a random 2-dimensional sampling of a population of cells. Because of this, it can more easily provide absolute values of volume and surface area, especially for highly-complex structures. It also allows study of individual variation among the cells, and study of structures which occur only infrequently.We have developed a system for 3-D reconstruction of objects from stereo-pair electron micrographs of thick specimens.

scholarly journals Tuning the hierarchical pore structure of graphene oxide through dual thermal activation for high-performance supercapacitor

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jeongpil Kim ◽  
Jeong-Hyun Eum ◽  
Junhyeok Kang ◽  
Ohchan Kwon ◽  
Hansung Kim ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Pore Structure ◽  
Specific Capacitance ◽  
Surface Area ◽  
Thermal Annealing ◽  
High Performance ◽  
Annealing Process ◽  
Supercapacitor Electrode ◽  
Simple Method ◽  
Surface Areas

AbstractHerein, we introduce a simple method to prepare hierarchical graphene with a tunable pore structure by activating graphene oxide (GO) with a two-step thermal annealing process. First, GO was treated at 600 °C by rapid thermal annealing in air, followed by subsequent thermal annealing in N2. The prepared graphene powder comprised abundant slit nanopores and micropores, showing a large specific surface area of 653.2 m2/g with a microporous surface area of 367.2 m2/g under optimized conditions. The pore structure was easily tunable by controlling the oxidation degree of GO and by the second annealing process. When the graphene powder was used as the supercapacitor electrode, a specific capacitance of 372.1 F/g was achieved at 0.5 A/g in 1 M H2SO4 electrolyte, which is a significantly enhanced value compared to that obtained using activated carbon and commercial reduced GO. The performance of the supercapacitor was highly stable, showing 103.8% retention of specific capacitance after 10,000 cycles at 10 A/g. The influence of pore structure on the supercapacitor performance was systematically investigated by varying the ratio of micro- and external surface areas of graphene.

The new face of large dams in the 21st century

2021 ◽  
Author(s):  
Atal Ahmadzai
Keyword(s):  
Surface Area ◽  
Aquatic Ecosystems ◽  
Energy Demand ◽  
Environmental Aspects ◽  
Water Insecurity ◽  
Surface Areas ◽  
Large Dams ◽  
Physical Attributes ◽  
Under Construction ◽  
Ecological Disturbances

Alerted by increasing water insecurity and energy demand, countries, mainly in the Global South, are building dams of unprecedented magnitude. Hundreds of large dams (≥ 100 metres) have been constructed since 2000, with hundreds more under construction. Analyses of the physical attributes of these dams present a concerning image. While they create expansive reservoirs with large surface areas, they have inefficient surface area-to-volume ratios ('S2VR'). Their unprecedented size and the reservoirs’ expansive surface area, indicate severe environmental costs, mainly through ecological disturbances to the (riverine) aquatic ecosystems; and greenhouse gas emissions (GHG). Other ecological costs due to the larger S2VR include a high evaporation rate and compromised biodiversity of a wider area, both up- and downstream. The safety and environmental aspects of these large dams should be robustly scrutinised.

scholarly journals The Effects of Methane Storage Capacity Using Upgraded Activated Carbon by KOH

2018 ◽  
Vol 8 (9) ◽  
pp. 1596 ◽  
Author(s):  
Jung Park ◽  
Gi Lee ◽  
Sang Hwang ◽  
Ji Kim ◽  
Bum Hong ◽  
...  
Keyword(s):  
Surface Area ◽  
Storage Capacity ◽  
Activated Carbons ◽  
Chemical Activation ◽  
High Surface ◽  
Heat Of Adsorption ◽  
Low Grade ◽  
Surface Areas ◽  
Ch4 Adsorption ◽  
Ch4 Storage

In this study, a feasible experiment on adsorbed natural gas (ANG) was performed using activated carbons (ACs) with high surface areas. Upgraded ACs were prepared using chemical activation with potassium hydroxide, and were then applied as adsorbents for methane (CH4) storage. This study had three principal objectives: (i) upgrade ACs with high surface areas; (ii) evaluate the factors regulating CH4 adsorption capacity; and (iii) assess discharge conditions for the delivery of CH4. The results showed that upgraded ACs with surface areas of 3052 m2/g had the highest CH4 storage capacity (0.32 g-CH4/g-ACs at 3.5 MPa), which was over two times higher than the surface area and storage capacity of low-grade ACs (surface area = 1152 m2/g, 0.10 g-CH4/g-ACs). Among the factors such as surface area, packing density, and heat of adsorption in the ANG system, the heat of adsorption played an important role in controlling CH4 adsorption. The released heat also affected the CH4 storage and enhanced available applications. During the discharge of gas from the ANG system, the residual amount of CH4 increased as the temperature decreased. The amount of delivered gas was confirmed using different evacuation flow rates at 0.4 MPa, and the highest efficiency of delivery was 98% at 0.1 L/min. The results of this research strongly suggested that the heat of adsorption should be controlled by both recharging and discharging processes to prevent rapid temperature change in the adsorbent bed.

scholarly journals The Peroneus Brevis and Plantar Fascia Insertions Are Related to Proximal Fifth Metatarsal Fractures

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0001
Author(s):  
Ali Hosseini ◽  
Pim Van Dijk ◽  
Sofie Breuking ◽  
Bryan Vopat ◽  
Daniel Guss ◽  
...  
Keyword(s):  
Surface Area ◽  
Fracture Mechanism ◽  
Soft Tissues ◽  
Plantar Fascia ◽  
Dorsal Side ◽  
Fracture Zones ◽  
Surface Areas ◽  
Metatarsal Bones ◽  
Metatarsal Fractures ◽  
Peroneus Brevis

Category: Midfoot/Forefoot Introduction/Purpose: Proximal fifth metatarsal fractures (PFMF) are among the most common fractures in the foot and can be categorized into three fracture zones [1]. To investigate the fracture mechanism of PFMF in different zones, a better understanding of the anatomy of the bone and its surrounding soft tissues is required. Both the plantar fascia (PF) and the peroneus brevis (PB) tendon insertions are at the base of the fifth metatarsal, and may contribute to the pathophysiology of PFMF. However, the role of the PB and PF insertions in the pathogenesis of PFMF remains unclear. The purpose of this study was to accurately define the footprint of the PB and PF insertions of the base of the 5th metatarsal in relation to the different zones of PFMF. Methods: 21 cadaveric fifth metatarsal bones were harvested from cadaveric feet. All bones were freed of any remaining soft tissue adherence, except for the PB and the PF insertions. Three reference screws with a diameter of 1 mm were placed and secured on each bone with 2 screws distally and 1 screw proximally for registration. All bones were CT scanned to create a 3D bone reconstruction. Next, the insertions of the PB and PF and the reference screws of each bone were digitized and then mapped to its corresponding 3D bone model. In order to describe the three different fracture zones of the 5th metatarsal, an established coordinate system was made for each bone to simulate separate fracture zones (Figure a) based on Lawrence guideline [1]. The shape, location and surface areas of both insertions and their relation to the different fractures zones were determined (Figure b). Results: The insertion of the PB was oval shaped and located on the dorsal side of the base, with a mean surface area of 88.1 ± 46.4 mm2. The PF was oval shaped and situated around the tip of tuberosity, with a mean surface area of 150.7±53.5 mm2. The PB insertion was present in zone 1 fractures in 100% (21/21) of the 5th metatarsal models and 29% (6/21) of the models for zone 2 fractures. The PF insertion was involved in 100% (21/21) of the 5th metatarsal models for zone 1 fractures and 43% (9/21) of the models for zone 2 fractures. Conclusion: Results of this study demonstrate that the insertion of both the PB and PF are involved in all zone 1 PFMF and a significant percentage of zone 2 PFMF. The location of tendon insertions affect the forces exerted on the bone, which may indicate a relation of the insertions of both the PB and the PF with the fracture mechanism of many zone 1 and 2 PFMF. Moreover, in the treatment of these fractures, care should be taken to maintain or restore the anatomy of these insertions to maximize functional outcomes.

The Relation of Vibrator Surface Area and Static Application Force to the Vibrator-to-Head Coupling

1968 ◽  
Vol 11 (4) ◽  
pp. 805-810 ◽  
Author(s):  
E. R. Nilo
Keyword(s):  
Young Adult ◽  
Surface Area ◽  
Unit Area ◽  
Bone Conduction ◽  
Pressure Force ◽  
Adult Men ◽  
Surface Areas ◽  
History Of ◽  
Preliminary Study ◽  
Bone Conduction Hearing

Twelve young adult men with normal hearing and no history of ear disease took part in our study of the relation of vibrator surface area and static application force to the vibrator-to-head coupling. For vibrator surface areas of 1.125, 2.25, and 4.5 cm 2 coupled to the forehead under static forces of 150, 300, and 600 gm, monaural thresholds of bone-conduction hearing were determined at frequencies 250, 500, 1000, and 2000 Hz. With surface area constant, threshold improvement was frequency dependent. It decreased with increasing frequency until at 2000 Hz it was minimal. In contrast to this, with force constant, the influence of surface area was observed to begin at 2000 Hz. Preliminary study suggests this influence would extend to 4000 Hz. In view of the respective influence of application force and surface area to bone-conduction hearing, equating vibrator-to-head coupling on the basis of pressure (force per unit area), when there are two or more vibrators, may not represent an adequate control.

scholarly journals Accurate Measurement of Surface Areas of Anatomical Structures Including Areas with an Irregular Relief: a Modern Solution to the Problem

2021 ◽  
Vol 9 (4) ◽  
pp. 90-95
Author(s):  
A. A. Воробьев ◽  
Yu. A. Makedonova ◽  
A. O. Solov'ev ◽  
D. Yu. D'yachenko ◽  
E. G. Bagrii ◽  
...  
Keyword(s):  
Surface Area ◽  
3D Model ◽  
Maxillofacial Surgery ◽  
Model Reconstruction ◽  
Maxillofacial Region ◽  
Anatomical Structures ◽  
Anatomical Region ◽  
Surface Areas ◽  
3D Model Reconstruction ◽  
Modern Solution

Relevance. The currently available methods for measuring anatomical areas with irregular relief do not claim to be accurate and easy to use.The aim of the study was to develop a method for measuring the surface area of an anatomical region (substructure) with an irregular relief.Material and methods. There was developed an option to measure the surface area of an anatomical region (substructure) with a complex relief in patients with pathology of the maxillofacial region and perineum using realistic 3D modeling.Results. The principle of the developed method is that, firstly, it is necessary to determine the patient's "zone of interest", where it is planned to measure the surface area; after that, digital photographs of the defined area are taken to obtain a sufficient number of images from the maximum number of available angles using a template with predefined dimensions for scaling. Then the obtained photographs are processed in the program for the 3D model reconstruction, and a realistic 3D model that correctly repeats the relief of the "zone of interest" and guarantees measurements of the surface area taking into account all its individual features is obtained. The method has been tested in obstetrics and gynecology, dentistry, maxillofacial surgery.Conclusion. This technique has been proved to be simple, accessible, fast, highly accurate in measuring the area of anatomical regions with complex relief. At the same time, the investigated object does not need fixation and prolonged immobility. A digital optical device is used contactless, the fact being significant in situations where it is necessary to comply with the rules of asepsis and antisepsis.

scholarly journals ISOPERIMETRIC INEQUALITIES FOR Lp GEOMINIMAL SURFACE AREA

2011 ◽  
Vol 53 (3) ◽  
pp. 717-726 ◽  
Author(s):  
BAOCHENG ZHU ◽  
NI LI ◽  
JIAZU ZHOU
Keyword(s):  
Convex Body ◽  
Surface Area ◽  
Type Inequality ◽  
Isoperimetric Inequalities ◽  
Surface Areas ◽  
Cyclic Inequality ◽  
Geominimal Surface Area

AbstractIn this paper, we establish a number of Lp-affine isoperimetric inequalities for Lp-geominimal surface area. In particular, we obtain a Blaschke–Santaló type inequality and a cyclic inequality between different Lp-geominimal surface areas of a convex body.

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