Structural and Material Mechanical Quality of Femoral Shafts in Rats Exposed to Simulated High Altitude from Infancy to Adulthood

2016 ◽  
Vol 17 (1) ◽  
pp. 50-53
Author(s):  
Clarisa Bozzini ◽  
Emilio O. Picasso ◽  
Graciela M. Champin ◽  
Rosa Maria Alippi ◽  
Carlos E. Bozzini
Keyword(s):  
High Altitude ◽  
Simulated High Altitude ◽  
Mechanical Quality

scholarly journals Probing of the internal damage morphology in multilayered high-temperature superconducting wires

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
You-He Zhou ◽  
Cong Liu ◽  
Lei Shen ◽  
Xingyi Zhang
Keyword(s):  
Magnetic Flux ◽  
Layer Structure ◽  
Extreme Environment ◽  
Uniaxial Tensile ◽  
Internal Damage ◽  
Amorphous Phases ◽  
Superconducting Wires ◽  
Mechanical Quality ◽  
Loading System

AbstractThe second generation HTS wires have been used in many superconducting components of electrical engineering after they were fabricated. New challenge what we face to is how the damages occur in such wires with multi-layer structure under both mechanical and extreme environment, which also dominates their quality. In this work, a macroscale technique combined a real-time magneto-optical imaging with a cryogenic uniaxial-tensile loading system was established to investigate the damage behavior accompanied with magnetic flux evolution. Under a low speed of tensile strain, it was found that the local magnetic flux moves gradually to form intermittent multi-stack spindle penetrations, which corresponds to the cracks initiated from substrate and extend along both tape thickness and width directions, where the amorphous phases at the tip of cracks were also observed. The obtained results reveal the mechanism of damage formation and provide a potential orientation for improving mechanical quality of these wires.

scholarly journals Cold stress in the harvest period: effects on tobacco leaf quality and curing characteristics

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yan Li ◽  
Ke Ren ◽  
Mengyang Hu ◽  
Xian He ◽  
Kaiyuan Gu ◽  
...  
Keyword(s):  
Cold Stress ◽  
High Altitude ◽  
Weather Forecast ◽  
Production Quality ◽  
Chemical Components ◽  
Leaf Quality ◽  
Tobacco Leaves ◽  
Tobacco Leaf ◽  
Antioxidant Enzyme System

Abstract Background Weather change in high-altitude areas subjects mature tobacco (Nicotiana tabacum L.) to cold stress, which damages tobacco leaf yield and quality. A brupt diurnal temperature differences (the daily temperature dropping more than 20 °C) along with rainfall in tobacco-growing areas at an altitude above 2450 m, caused cold stress to field-grown tobacco. Results After the flue-cured tobacco suffered cold stress in the field, the surface color of tobacco leaves changed and obvious large browning areas were appeared, and the curing availability was extremely poor. Further research found the quality of fresh tobacco leaves, the content of key chemical components, and the production quality were greatly reduced by cold stress. We hypothesize that cold stress in high altitude environments destroyed the antioxidant enzyme system of mature flue-cured tobacco. Therefore, the quality of fresh tobacco leaves, the content of key chemical components, and the production quality were greatly reduced by cold stress. Conclusion This study confirmed that cold stress in high-altitude tobacco areas was the main reason for the browning of tobacco leaves during the tobacco curing process. This adverse environment seriously damaged the quality of tobacco leaves, but can be mitigated by pay attention to the weather forecast and pick tobacco leaves in advance.

scholarly journals Ultraviolet Transparency of Plastic Films Determines the Quality of Lettuce (Lactuca sativa L.) Grown in a Greenhouse

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 358
Author(s):  
Deissy Giovanna Quintero-Arias ◽  
John Fabio Acuña-Caita ◽  
Carlos Asensio ◽  
Juan Luis Valenzuela
Keyword(s):  
Ultraviolet Radiation ◽  
High Altitude ◽  
Dry Weight ◽  
Yield Component ◽  
Plastic Film ◽  
Area Index ◽  
Plastic Films ◽  
High Solar Radiation ◽  
Cycle Growth

The quality of red lettuce is based on the content of anthocyanin pigments, and the content of these pigments increases when the plant receives ultraviolet radiation. Lettuce crops are increasingly being grown in greenhouses to provide better quality fresh lettuce; however, both quality and productivity are affected by the type of cover used. The effects of UV-transparent and UV-blocking plastic films on the growth and quality of three lettuce cultivars (‘Casabella’ and ‘Vera’, which are both green leaf, and ‘Lollo Rosso’, which is red leaf) were investigated. The crop was cultivated at an altitude of 2576 m a.s.l. to naturally expose it to high ultraviolet radiation. The height and diameter of plants, fresh and dry weight, leaf area index, chlorophyll fluorescence, and leaf colour were determined throughout the crop cycle. Growth characteristics were not significantly influenced by the plastic film in all cultivars, probably due to the high altitude and the high solar radiation received. The UV-transparent film could increase the red colour in ‘Lollo Rosso’, and a higher commercial quality was achieved. No effect of the plastic film on the yield component was observed in the ‘Casabella’ and ‘Vera’ cultivars. The findings of this study provide guidance on what cultivar and plastic film must be used in high-altitude areas where the solar and UV radiation is high.

Reduction of ICa,Land Ito1Density in Hypertrophied Right Ventricular Cells by Simulated High Altitude in Adult Rats

1997 ◽  
Vol 29 (1) ◽  
pp. 193-206 ◽  
Author(s):  
Christophe Chouabe ◽  
Leon Espinosa ◽  
Pierre Megas ◽  
Abderrazak Chakir ◽  
Oger Rougier ◽  
...  
Keyword(s):  
Right Ventricular ◽  
High Altitude ◽  
Adult Rats ◽  
Ventricular Cells ◽  
Simulated High Altitude

Relationship between Behavior in a Stress Situation and Later Separation from Flight Training with Expressed Anxiety toward Flying

1956 ◽  
Vol 2 (3) ◽  
pp. 393-397
Author(s):  
Robert B. Voas ◽  
John T. Bair ◽  
Rosalie K. Ambler
Keyword(s):  
High Altitude ◽  
Training Program ◽  
Flight Training ◽  
Stress Situation ◽  
Simulated High Altitude ◽  
Development Of Anxiety ◽  
The Relationship

The purpose of this research was to determine the relationship between reactions of cadets during simulated high altitude in a decompression chamber and the later development of anxiety toward flying as reported in terminal interviews. The results for 1540 cadets indicated that significantly more of those who withdrew because of anxiety toward flying had anxiety reactions in the decompression chamber than of those who completed the Naval Air Training Program.

Mechanical quality of tissue engineered cartilage: Results after 6 and 12 weeksin vivo

2000 ◽  
Vol 53 (6) ◽  
pp. 673-677 ◽  
Author(s):  
Georg N. Duda ◽  
Andreas Haisch ◽  
Michaela Endres ◽  
Christian Gebert ◽  
Daniel Schroeder ◽  
...  
Keyword(s):  
Mechanical Quality ◽  
Engineered Cartilage

Acute hypoxia in a simulated high-altitude airdrop scenario due to oxygen system failure

2017 ◽  
Vol 123 (6) ◽  
pp. 1443-1450 ◽  
Author(s):  
William Ottestad ◽  
Tor Are Hansen ◽  
Gaurav Pradhan ◽  
Jan Stepanek ◽  
Lars Øivind Høiseth ◽  
...  
Keyword(s):  
High Altitude ◽  
Acute Hypoxia ◽  
Supplemental Oxygen ◽  
Cerebral Oximetry ◽  
Arterial Oxygen ◽  
Hypoxic Exposure ◽  
System Failure ◽  
Oxygen System ◽  
Simulated High Altitude ◽  
Oxygen Tensions

High-Altitude High Opening (HAHO) is a military operational procedure in which parachute jumps are performed at high altitude requiring supplemental oxygen, putting personnel at risk of acute hypoxia in the event of oxygen equipment failure. This study was initiated by the Norwegian Army to evaluate potential outcomes during failure of oxygen supply, and to explore physiology during acute severe hypobaric hypoxia. A simulated HAHO without supplemental oxygen was carried out in a hypobaric chamber with decompression to 30,000 ft (9,144 m) and then recompression to ground level with a descent rate of 1,000 ft/min (305 m/min). Nine subjects were studied. Repeated arterial blood gas samples were drawn throughout the entire hypoxic exposure. Additionally, pulse oximetry, cerebral oximetry, and hemodynamic variables were monitored. Desaturation evolved rapidly and the arterial oxygen tensions are among the lowest ever reported in volunteers during acute hypoxia. PaO2 decreased from baseline 18.4 (17.3–19.1) kPa, 138.0 (133.5–143.3) mmHg, to a minimum value of 3.3 (2.9–3.7) kPa, 24.8 (21.6–27.8) mmHg, after 180 (60–210) s, [median (range)], N = 9. Hyperventilation with ensuing hypocapnia was associated with both increased arterial oxygen saturation and cerebral oximetry values, and potentially improved tolerance to severe hypoxia. One subject had a sharp drop in heart rate and cardiac index and lost consciousness 4 min into the hypoxic exposure. A simulated high-altitude airdrop scenario without supplemental oxygen results in extreme hypoxemia and may result in loss of consciousness in some individuals. NEW & NOTEWORTHY This is the first study to investigate physiology and clinical outcome of oxygen system failure in a simulated HAHO scenario. The acquired knowledge is of great value to make valid risk-benefit analyses during HAHO training or operations. The arterial oxygen tensions reported in this hypobaric chamber study are among the lowest ever reported during acute hypoxia.

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