The Effect of Three Antimetabolites on Sea-Urchin Development

Development ◽  
1954 ◽  
Vol 2 (3) ◽  
pp. 216-226
Author(s):  
Sven Hörstadius ◽  
Tryggve Gustafson
Keyword(s):  
Growth Factor ◽  
Sea Urchin ◽  
Lithium Ion ◽  
Metabolic Effects ◽  
Phenyllactic Acid ◽  
Thiocyanate Ion ◽  
The Past ◽  
Psammechinus Miliaris ◽  
Embryonic Metabolism ◽  
Insight Into

The metabolic background for morphogenesis has been the object of intense investigations during the past decades. As an approach to this problem the metabolic effects of the vegetalizing lithium ion and the animalizing thiocyanate ion have been investigated (cf. Lindahl, 1936, and Gustafson, 1952). The studies of antimetabolites (growth-factor analogues) during the last decade have opened pathways for interfering with the embryonic metabolism in a predictable way. Using the antimetabolites it is now possible to get a deeper insight into the relation between metabolic processes and different developmental trends. The effect of some antimetabolites on the early development of the eggs of Psammechinus miliaris were studied during the summer of 1953 at Kristinebergs Zoologiska Station, Sweden. The results obtained with 8-chloroxanthine, β-phenyllactic acid, and 3-acetylpyridine will be reported here. The substances were obtained from the Nutritional Biochemicals Corporation, Cleveland, Ohio. The statements regarding the antimetabolic character of the substances are takenfrom the catalogue of that firm.

The Fertilization Reaction in the Sea-Urchin

1951 ◽  
Vol 28 (3) ◽  
pp. 403-416 ◽  
Author(s):  
LORD ROTHSCHILD ◽  
M. M. SWANN
Keyword(s):  
Sea Urchin ◽  
Inverse Relationship ◽  
Physical Nature ◽  
Conduction Time ◽  
The Past ◽  
Sperm Density ◽  
Psammechinus Miliaris ◽  
Sperm Suspension ◽  
Source Of Error ◽  
Kinetic Treatment

1. Unfertilized eggs of the sea-urchin (Psammechinus miliaris) were left for known but varying times in contact with homologous sperm suspensions containing known numbers of spermatozoa. Counts were made of the numbers of fertilized and unfertilized eggs at times ranging from 0 to 300 sec. after mixing. 2. If spermatozoa are considered as particles moving in random directions, the frequency of sperm-egg collisions can be calculated if the density and mean speed of the sperm suspension are known. 3. The information in (1) and (2) enables an estimate to be made of the probability of a successful sperm-egg collision. 4. The estimated probability of a successful collision, p, varies with sperm density, d. At the lowest density used, 7.44x104/ml., p was found to be 0.226. At the highest density, 9.62/106/ml., p was about 0.011. The inverse relationship between p and d may be due to sperm-sperm interactions of a physical nature. 5. The presence of jelly round the eggs increases p. This disposes of the possibility, raised in the past, that egg jelly may have an adverse effect on the fertilizing capacity of homologous spermatozoa under normal conditions of fertilization. 6. The technique of subjecting eggs to a pre-determined number of collisions facilitates investigation of the conduction time of the block to polyspermy. Preliminary experiments suggest that the conduction time may be of the order of seconds rather than fractions of a second. 7. Sources of error arising from the ‘kinetic’ treatment of sperm suspensions are discussed in detail. One source of error concerns the alleged chemotaxis of spermatozoa towards eggs and egg secretions. No chemotaxis was observed.

Recovery boiler sootblowers: History and technological advances

TAPPI Journal ◽  
2015 ◽  
Vol 14 (1) ◽  
pp. 51-60
Author(s):  
HONGHI TRAN ◽  
DANNY TANDRA
Keyword(s):  
Cfd Modeling ◽  
Computing Systems ◽  
The Past ◽  
Technological Advances ◽  
Recovery Boilers ◽  
Computational Fluid Dynamics Cfd ◽  
Recovery Boiler ◽  
Steam Parameters ◽  
Insight Into ◽  
Deposit Removal

Sootblowing technology used in recovery boilers originated from that used in coal-fired boilers. It started with manual cleaning with hand lancing and hand blowing, and evolved slowly into online sootblowing using retractable sootblowers. Since 1991, intensive research and development has focused on sootblowing jet fundamentals and deposit removal in recovery boilers. The results have provided much insight into sootblower jet hydrodynamics, how a sootblower jet interacts with tubes and deposits, and factors influencing its deposit removal efficiency, and have led to two important innovations: fully-expanded sootblower nozzles that are used in virtually all recovery boilers today, and the low pressure sootblowing technology that has been implemented in several new recovery boilers. The availability of powerful computing systems, superfast microprocessors and data acquisition systems, and versatile computational fluid dynamics (CFD) modeling capability in the past two decades has also contributed greatly to the advancement of sootblowing technology. High quality infrared inspection cameras have enabled mills to inspect the deposit buildup conditions in the boiler during operation, and helped identify problems with sootblower lance swinging and superheater platens and boiler bank tube vibrations. As the recovery boiler firing capacity and steam parameters have increased markedly in recent years, sootblowers have become larger and longer, and this can present a challenge in terms of both sootblower design and operation.

Upcoming Drifts In Bio-Similars

2020 ◽  
Vol 15 ◽  
Author(s):  
Geeta Aggarwal ◽  
Manju Nagpal ◽  
Ameya Sharma ◽  
Vivek Puri ◽  
Gitika Arora Dhingra
Keyword(s):  
Metabolic Diseases ◽  
Market Competition ◽  
Current Status ◽  
Medicinal Products ◽  
The Past ◽  
Biologic Activity ◽  
Emerging Trends ◽  
Regulatory Guidelines ◽  
Food Drug Administration ◽  
Insight Into

Background: Biopharmaceuticals such as Biologic medicinal products have been in clinical use over the past three decades and have benefited towards the therapy of degenerative and critical metabolic diseases. It is forecasted that market of biologics will be going to increase at a rate of 20% per year, and by 2025, more than ˃ 50% of new drug approvals may be biological products. The increasing utilization of the biologics necessitates for cost control, especially for innovators products that have enjoyed a lengthy period of exclusive use. As the first wave of biopharmaceuticals is expired or set to expire, it has led to various opportunities for the expansion of bio-similars i.e. copied versions of original biologics with same biologic activity. Development of biosimilars is expected to promote market competition, meet worldwide demand, sustain the healthcare systems and maintain the incentives for innovation. Methods: Appraisal of published articles from peer reviewed journals, PubMed literature, latest news and guidelines from European Medicine Agency, US Food Drug Administration (FDA) and India are used to identify data for review. Results: Main insight into the quality requirements concerning biologics, current status of regulation of biosimilars and upcoming challenges lying ahead for the upgrading of marketing authorization of bio-similars has been incorporated. Compiled literature on therapeutic status, regulatory guidelines and the emerging trends and opportunities of biosimilars has been thoroughly stated. Conclusion: Updates on biosimilars will support to investigate the possible impact of bio-similars on healthcare market.

Cybersecurity Teamwork: A Review of Current Practices and Suggested Improvements

2020 ◽  
Vol 64 (1) ◽  
pp. 451-455
Author(s):  
Richard J. Simonson ◽  
Joseph R. Keebler ◽  
Mathew Lessmiller ◽  
Tyson Richards ◽  
John C. Lee
Keyword(s):  
Cyber Security ◽  
Cyber Attacks ◽  
Team Science ◽  
The Past ◽  
Insight Into ◽  
Current Practices

As cyber-attacks and their subsequent responses have become more frequent and complex over the past decade, research into the performance and effectiveness of cybersecurity teams has gained an immense amount of traction. However, investigation of teamwork in this domain is lacking due to the exclusion of known team competencies and a lack of reliance on team science. This paper serves to provide insight into the benefit that can be gained from utilizing the extant teamwork literature to improve teams’ research and applications in the domain of cyber-security.

An insight into the effect of g-C3N4 support on the enhanced performance of ZnS nanoparticles as anode material for lithium-ion and sodium-ion batteries

2021 ◽  
pp. 137715
Author(s):  
Dipa D. Pathak ◽  
Dimple P. Dutta ◽  
Balaji R. Ravuri ◽  
Anand Ballal ◽  
Akhilesh C. Joshi ◽  
...  
Keyword(s):  
Anode Material ◽  
Lithium Ion ◽  
Sodium Ion ◽  
Sodium Ion Batteries ◽  
Zns Nanoparticles ◽  
Insight Into

New Insight into Microstructure Engineering of Ni‐Rich Layered Oxide Cathode for High Performance Lithium Ion Batteries

2021 ◽  
pp. 2010095
Author(s):  
Chul‐Ho Jung ◽  
Do‐Hoon Kim ◽  
Donggun Eum ◽  
Kyeong‐Ho Kim ◽  
Jonghyun Choi ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
High Performance ◽  
Lithium Ion ◽  
Layered Oxide ◽  
Oxide Cathode ◽  
Insight Into

scholarly journals An Insight into Saponins from Quinoa (Chenopodium quinoa Willd): A Review

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1059 ◽  
Author(s):  
Khadija El Hazzam ◽  
Jawhar Hafsa ◽  
Mansour Sobeh ◽  
Manal Mhada ◽  
Moha Taourirte ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Bitter Taste ◽  
Biological Activities ◽  
Chenopodium Quinoa ◽  
Toxic Effects ◽  
Mechanical Abrasion ◽  
Important Group ◽  
The Past ◽  
Wide Range ◽  
Insight Into

Saponins are an important group found in Chenopodium quinoa. They represent an obstacle for the use of quinoa as food for humans and animal feeds because of their bitter taste and toxic effects, which necessitates their elimination. Several saponins elimination methods have been examined to leach the saponins from the quinoa seeds; the wet technique remains the most used at both laboratory and industrial levels. Dry methods (heat treatment, extrusion, roasting, or mechanical abrasion) and genetic methods have also been evaluated. The extraction of quinoa saponins can be carried out by several methods; conventional technologies such as maceration and Soxhlet are the most utilized methods. However, recent research has focused on technologies to improve the efficiency of extraction. At least 40 saponin structures from quinoa have been isolated in the past 30 years, the derived molecular entities essentially being phytolaccagenic, oleanolic and serjanic acids, hederagenin, 3β,23,30 trihydroxy olean-12-en-28-oic acid, 3β-hydroxy-27-oxo-olean-12en-28-oic acid, and 3β,23,30 trihydroxy olean-12-en-28-oic acid. These metabolites exhibit a wide range of biological activities, such as molluscicidal, antifungal, anti-inflammatory, hemolytic, and cytotoxic properties.

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