703 research outputs found
Artemisia fragransWilld. Essential Oil: Chemical Profile and Insecticidal Potential against the Confused Flour Beetle, Tribolium confusum du Val.
No full textThe confused flour beetle, Tribolium confusum du Val, is one of the cosmopolitan and polyphagous storage insect pests. The frequent application of chemical insecticides has resulted in several side effects, including threats to human health and non-target organisms and the resistance of insect pests. In the current study, the fumigant toxicity and feeding deterrence potential of Artemisia fragrans Willd. essential oil on T. confusum adults were investigated. The essential oil was rich in
terpenic compounds, in which α-thujone (27.8%) and 1,8-cineole (22.8%) were dominant. The essential oil displayed significant fumigant toxicity on T. confusum, where a concentration of 35.3 μL/L caused 100% mortality of the treated adults after 48 h. The LC30 and LC40 values (lethal concentrations to kill 30% and 40% of tested insects: 15.1 and 18.4 μL/L, respectively) significantly decreased the nutritional indices of the pest, including the consumption index, relative consumption rate, and
relative growth rate. The feeding deterrence index of the essential oil were calculated as being 62.29 and 48.66% for the concentrations of 15.1 and 18.4 μL/L after 5 days, respectively. Accordingly, A. fragrans essential oil can be considered an efficient, available, and natural alternative to detrimental chemical pesticides in the management of T. confusum
Probing the Phytochemical Composition and Antioxidant Activity of Moringa oleifera under Ideal Germination Conditions
No full textMoringa oleifera is a rich source of polyphenols whose contents and profile may vary according to environmental conditions, harvest season, and plant tissue. The present study aimed to characterize the profile of phenolic compounds in different tissues of M. oleifera grown under different temperatures (25, 30, and 35 °C), using HPLC/MS, as well as their constituent phytochemicals and in vitro antioxidant activities. The in vitro antioxidant activity of the extracts was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-3-ethylenebenzothiozoline-6-sulfonicacid (ABTS), and ferric-reducing antioxidant power (FRAP) methods. The polyphenolic compounds were mainly found in the leaves at 30 °C. UPLC/QTOF-MS allowed for the identification of 34 polyphenolic components in seedlings, primarily consisting of glucosides, phenols, flavonoids, and methoxy flavones. At 30 °C, the specific activities of antioxidative enzymes were the highest in leaves, followed by seedlings and then seeds. The leaf and seed extracts also exhibited a greater accumulation of proline, glycine betaine, and antioxidants, such as ascorbic acid, and carotenoids, as measured by the inhibition of ROS production. We found that changes in the expression levels of the validated candidate genes Cu/Zn-SOD, APX, GPP, and TPS lead to significant differences in the germination rate and biochemical changes. These findings demonstrate that M. oleifera plants have high concentrations of phytochemicals and antioxidants, making them an excellent choice for further research to determine their use as health-promoting dietary supplements.fals
Toward monitoring and estimating the size of the HFO-contaminated seabed around a shipwreck using MBES backscatter data
No full textFunding Information: The authors are grateful to three anonymous reviewers for their constructive criticism and valuable comments. The authors express their gratitude to the Maritime Institute in Gdansk for making the final version of the report (Maritime Institute in Gdansk, 2016) available. The second author appreciates the support of the Gdynia Maritime University in funding this research through internal grant WN/PZ/2021/02. Funding Information: The second author appreciates the support of the Gdynia Maritime University in funding this research through internal grant WN/PZ/2021/02 . Publisher Copyright: © 2021Despite a progressive reduction of oil spills caused by the activity of maritime transportation, the latent sources of pollution still exist. Although the harmful impact of heavy fuel oil (HFO) on the marine environment is widely known, many shipwrecks cause contamination of the surrounding areas. In this paper, an approach to monitor the area of the HFO spill around a shipwreck is made using a bottom backscattering strength (BBS) obtained by a multibeam echosounder (MBES). As a case study, the s/s Stuttgart wreck located in the Gulf of Gdansk (Poland) is verified. Two different measurement campaigns have been carried out in shallow waters using low (190 kHz) and high (420 kHz) MBES frequency. The results indicate that the polluted area around s/s Stuttgart was estimated at 49.1 ha, which is around 18.3% more in comparison to the geological surveys made four years earlier.Peer reviewe
The Weight and Hopcount of the Shortest Path in the Complete Graph with Exponential Weights
No full textBoth the hopcount HN (the number of links) and the weight WN (the sum of the weights on links) of the shortest path between two arbitrary nodes in the complete graph KN with i.i.d. exponential link weights is computed. We consider the joint distribution of the pair (HN,WN) and derive, after proper scaling, the joint limiting distribution. One of the results is that HN and WN, properly scaled, are asymptotically independent.Delft Institute of Applied MathematicsElectrical Engineering, Mathematics and Computer Scienc
Matricaria genus as a source of antimicrobial agents: From farm to pharmacy and food applications
No full textMatricaria is a widespread genus of flowering plants of the family Asteraceae that grow in temperate regions of Europe, Asia, America and Africa. Some of the species are also naturalized in Australia. Some species of this genus such as Chamomiles are recognized medicinal plants and cultivated in several countries for commercial purposes: to obtain its blue essence, as herbal tea, and for pharmaceutical or cosmeceutical uses. The phytochemical composition of Matricaria spp. includes volatile terpenoids (e.g., α-bisabolol, bisabolol oxide A and B, β-trans-farnesene and chamazulene), sesquiterpene lactones such as matricin, and phenolic compounds (flavonoids, coumarins and phenolic acids). Their essential oil is obtained from the fresh or dried inflorescences by steam distillation, and additionally cohobation of the remaining water. The volatile composition of the essential oil, especially the content of the valuable components α-bisabolol and chamazulene, depends on the plant part, origin and quality of the source, genetic, and environmental factors. Moreover, other parameters, such as season of harvest and methods of extraction, can affect the extraction yield of the essential oils/extracts, their composition and, therefore, their bioactivity. Due to the importance of this genus and particularly M. recutita (M. chamomilla), this review focus on its cultivation, factor affecting essential oils’ composition and their role in traditional medicine, as antibacterial agents and finally as food preservatives
Feasibility of abdominoplasty with Cesarean section [Retraction]
No full textThe Editor-in-Chief and Publisher of the International Journal of Women’s Health have been alerted by Dr Nadine Sherif, the corresponding author, to unacceptable levels of duplication with a previously published paper: Ali A, Essam A. Abdominoplasty Combined with Cesarean Delivery: Evaluation of the Practice. Aesthetic Plastic Surgery. 2011;35(1):80–86.It is worth noting that this paper was peer-reviewed by two peer-reviewers and the Editor-in-Chief of the International Journal of Women’s Health before publication. The paper concerned is: Thabet WN, Hossny AS, Sherif NA. Feasibility of abdominoplasty with Cesarean section. International Journal of Women’s Health. 2012;4:115–121
A concept of critical safety area applicable for an obstacle-avoidance process for manned and autonomous ships
No full textFunding Information: This research work was supported by the Gdynia Maritime University internal grant WN/PZ/2021/02. Funding Information: The author is grateful to three anonymous reviewers for their constructive criticism and valuable comments. The author expresses his gratitude to Prof. Jerzy Matusiak of Aalto University for making the LaiDyn code available, as well as to Dr. Tomasz Hinz of Waterborne Transport Innovation Foundation for preparing LaiDyn output files containing ship trajectories. This research work was supported by the Gdynia Maritime University internal grant WN/PZ/2021/02. Publisher Copyright: © 2021 The Author(s)In times of increased automation of maritime transportation, ship collision with a stationary obstacle (allision) remains a significant problem. There are many existing solutions rooted primarily in the concept of ship domain and path-planning algorithms. However, among these, a geometrical approach to the determination of a required maneuvering area considering the dynamic nature of ship operations in close-quarters situations is still missing. Therefore, an improved concept of the CADCA (Collision Avoidance Dynamic Critical Area) is introduced for the case of ship allision. The CADCA is a deterministic zone that geometrically delimits required maneuvering space of a vessel. Its shape changes depending on the operational parameters of a ship, such as the magnitude of rudder angle, initial forward speed, or planned alteration of the course. In contrast to ship domain, the CADCA is determined using the critical distance between two objects called MDTC (Minimum Distance to Collision). Therefore, the CADCA concept can be used to appoint a position of no-return in a close-quarters situation, so as to determine the time and distance of the last-minute maneuver. An improved method of CADCA determination is introduced, along with an investigation of operational factors influencing the ship's critical area in allision scenarios. The simulations have been conducted for large passenger and container ship in encounters with various stationary obstacles differing in size and shape. The results indicate that from the operational point of view, a deflection of the rudder is the most influencing factor on the size of the CADCA, while the impact of ship speed is negligible for the investigated vessels. Besides, various applications of the CADCA are proposed and discussed for both manned and prospective autonomous vessels.Peer reviewe
Corrosion prevention of stell structures for Sri Lanka Author Premachandrasiri, W.N.
No full textSri Lanka has made a significant development in the design and construction sector during the last 10 years. The use of steel is one of the governing construction materials in the industries. One of the major concerns of existing steel structures is the durability. Corrosion and deterioration have become major challenges in the lifetime of the structure, as it is one of the major public focuses on the structures.
Standards are intended to assist engineers and corrosion experts in adopting best practice in corrosion protection of structural steel at new constructions with proper identification of an actual exposure. There are six environmental corrosivity categories according to BS ISO 12944 as C1, C2 C3, C4, C5 and C5 –M. Those are according to BS standard and they should be adapted for Sri Lanka. In this research environmental corrosivity category of SC1, SC2, SC3 and SC4 are classified for Sri Lanka considering corrosion affecting factors temperature, rainfall, coastal region and industrial zones. A field survey was carried out in different locations of the structure in the country to identify the pattern of corrosion according to variation of corrosion affecting factors.
Among the methods used to clean the surface of the steel before applying corrosion protection, sand blasting cleans best. However, it cannot be carried out in every location due to environmental issues and equipment required. Steel surface is difficult to clean using light tools because temporary stabilized corroded layer on the steel surface. If we change this surface (Convert surface grade A to Surface grade B), the light tools can be used for the surface preparation. Therefore a new method is proposed to change this surface grade. Firstly, sea water is sprayed on to the surface to increase the rate of corrosion and left for a day for rust to appear. Then it is cleaned by fresh water and surface salinity level should be checked using salinity meter. Then the surface can be prepared using “Cup-Brush application” method without using sand blasting. By this method well cleaned surface can be obtained and then the surface protection primer is applied on it immediately. This surface protection primer type and primer and paint thickness should be defined according to environmental corrosivity category
My Favorite Integer Sequences
No full textAbstract. This paper gives a brief description of the author's database of integer sequences, now over 35 years old, together with a selection of a few of the most interesting sequences in the table. Many unsolved problems are mentioned
Prevalence of antibodies against Saint Louis encephalitis and Jamestown Canyon viruses in California horses
No full textJamestown Canyon (JC) and Saint Louis encephalitis (SLE) viruses are mosquito-transmitted viruses that have long been present in California. The objective of this study was to determine the seroprevalence of these two viruses in horses prior to the introduction of West Nile (WN) virus. Approximately 15% of serum samples collected in 1998 from 425 horses on 44 equine operations horses throughout California had serum antibodies to JC virus, whereas antibodies were not detected to SLE virus. The results indicate that horses in California were commonly infected prior to 1998 with mosquito-transmitted Bunyaviruses that are identical or closely related to JC virus, but not with SLE virus. The different seroprevalence of SLE and JC viruses in horses likely reflects the unique ecology of each virus, and it is predicted that WN virus will have a wider distribution in California than closely related SLE virus.ID: 6643; Accession Number: 20043069109. Publication Type: Journal Article. Language: English. Language of Summary: French. Number of References: 32 ref. Subject Subsets: Veterinary Science; Veterinary Science; Medical & Veterinary EntomologySource type: Electronic(1)http://search.ebscohost.com/login.aspx?direct=true&db=lah&AN=20043069109&site=ehost-liv
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