37 results on '"Ayodele, M."'
Search Results
2. A biosystematic evaluation of the relationship between three allopatric shrubby species of Vernonia Schreb. (Asteraceae) in Nigeria
- Author
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Ayodele, M S, Olorode, O, and BioStor
- Published
- 2005
3. BENJAMIN-BONA-MAHONY EQUATION SOLUTION USING THE LAPLACE HOMOTOPY PERTURBATION METHOD.
- Author
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OLUBANWO, O. O., ONITILO, S. A., OLASUPO, A. O., AJANI, A. S., AYODELE, M. A., ADEBESIN, A. A., and ODETUNDE, O. S.
- Subjects
NONLINEAR equations ,EQUATIONS ,PROBLEM solving - Abstract
The mixture of Laplace transform and Homotopy perturbation was used to solve Benjamin-Bona-Mahony problems. In this research work, three examples of Benjamin-Bona-Mahony equations were considered. The numerical solutions were obtained by Laplace Homotopy Perturbation method. The method was introduced as essential tool to linearize all the associated nonlinear terms in the equations since Laplace transform method alone cannot handle nonlinear terms. The solutions are series form which quickly converges precisely to their exact value with few iterations. The solution obtained by Laplace Homotopy perturbation method accord well with solutions obtained by using other existing methods. The method of Laplace Homotopy perturbation is very powerful integral transform methods in solving some nonlinear Equations like Benjamin-Bona-Mahony equations. [ABSTRACT FROM AUTHOR]
- Published
- 2023
4. A COMPARATIVE ANALYTICAL SOLUTION OF TELEGRAPH EQUATION.
- Author
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OJIMADU, U. H., USMAN, M. A., OLASUPO, A. O., OLUBANWO, O. O., AYODELE, M. A., and SULAIMAN, M. A.
- Subjects
TELEGRAPH & telegraphy ,ANALYTICAL solutions ,DECOMPOSITION method ,NONLINEAR differential equations ,PARTIAL differential equations - Abstract
In this paper, two methods Adomian Decomposition Method (ADM) and Laplace Adomian Decomposition Method (LADM) were adopted to solve the telegraph equation. The essence of this research is to establish a relationship between the two analytical methods. It was observed that the two methods were consistent as the results obtained from the numerical examples on the two methods were the same. We also generated the telegraph equation to help provide a solid basis for the application of the telegraph equation. The telegraph equation is one of the nonlinear partial differential equation and it’s application to solving practical problems were suggested for further studies. [ABSTRACT FROM AUTHOR]
- Published
- 2023
5. Effect of silica on the mechanical properties of palm kernel shell based automotive brake pad
- Author
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Olanrewaju M. Adesusi, Iliyas K. Okediran, Olawale U. Dairo, Salami O. Ismailia, Ayodele M. Adedayo, and Olayide R. Adetunji
- Abstract
This research investigated the role of silica on palm kernel shell (PKS) as friction lining materials in automotive brake pad production. The friction materials were crushed, milled and sieved into four different particle sizes of 100, 150, 200 and 350 µm. The formulations weight percentages employed included Resin (20%), steel slag (15%) and carbon black (5%) while palm kernel shell and silica were varied for each particle size. Individual formulation was mixed for about 10 minutes until formation of homogeneous mixture. Homogeneous formulation A, B, C and D respectively, was compacted into mould and later sintered at 150 oC for 10 minutes in electric furnace and subsequently treated to enhance quality. Produced samples were characterized and evaluated for surface hardness (SH), compressive strength (CS), flame resistance (FR), oil absorption (OA), water absorption (WA) and wear rate (WR). The particles were also characterized using Scanning Electron Microscope. The results revealed that sample D had highest SH and CS values of 105.5 Brinell hardness number (BHN) and 115.2 N/mm2 respectively with decreasing values as particle size increases. FR decreased from samples A to D, and also decreased as particle size increased. Deductively, Sample B with the sieved grade of 100 µm was the best with SH as 99.14 BHN, CS as 105.6 N/mm2, WR as 4.15%, FR as 38.98%, and WA rate as 4.26 % and CF as 0.45 and OA rate as 0.381%. Conclusively, this research developed a high quality eco-friendly PKS particle composite for the production of brake pad.
- Published
- 2022
- Full Text
- View/download PDF
6. Antifungal Potential of Four Aloe Species
- Author
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Technical staffs, Federal University of Technology Akure, Dr. Fayehun, Dr. Taye Temikotan, Ayeni, Oluwaseun Ruqayah, Ajayi, Ayodele M., Akinyele, Benjamin O., Hassan, Ganiyu F., Technical staffs, Federal University of Technology Akure, Dr. Fayehun, Dr. Taye Temikotan, Ayeni, Oluwaseun Ruqayah, Ajayi, Ayodele M., Akinyele, Benjamin O., and Hassan, Ganiyu F.
- Abstract
Increase in the use of biologically based fungicides for controlling plant and human pathogens in the recent years have led to this research to determine the efficacy of solvent type, to determine the best species of aloe for breeding new variety with more potent biocides for controlling these fungal pathogens under reducing the use of synthetic fungicides which have long term adverse effect on the environment, plant and the end users. The biocides of the leaves and the roots of four species of aloe (Aloe keayi, Aloe macrocarpa var. major, Aloe schwenfurthii and Aloe vera) were extracted with four different solvents (i.e. acetone, ethanol, methanol and hot water) while their fungicidal properties were investigated against three fungal pathogens of crops (Sclerotium rolfsii, Trichoderma rubrum and Colletotrichum lindemuthiamum). The result shows that A. macrocarpa var. major and A. schwenfurthii are the most suitable parental genotypes for the breeding of an aloe with more potent biocides.
- Published
- 2022
7. Purification and partial characterization of serine alkaline metalloprotease from Bacillus brevis MWB-01
- Author
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Olajuyigbe, Folasade M and Falade, Ayodele M
- Published
- 2014
- Full Text
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8. Seed Dressing with Aqueous Allium sativum L. Extracts Enhanced the Tolerance of Maize Plant to Stalk and Ear Rot Disease Caused by Fusarium verticillioides (Sacc.) Nirenberg
- Author
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Ayodele. M. Ajayi
- Subjects
Fusarium ,Inoculation ,food and beverages ,General Medicine ,Biology ,biology.organism_classification ,Allium sativum ,chemistry.chemical_compound ,Horticulture ,chemistry ,Stalk ,Germination ,Transplanting ,Mycotoxin ,Mycelium - Abstract
Stalk and ear rot is one of the most common fungal disease of maize. Significant crop failure and yield loss, arising from the disease, are reported annually. Maize grains infected with the pathogen pose serious threat to human and animal health, owing to mycotoxins contamination. The present study evaluated aqueous extracts from Allium sativum in the management of the disease. Four concentrations of the extracts were evaluated against the pathogen in vitro. The most promising concentrations, were applied as seed dressing agents in vivo at 5, 10 and 15-minutes duration for each concentration. Garlic extracts-dressed seeds were then transferred to F. verticilliodes infested medium and allowed to germinate and grow for 9 days. Seedlings were transplanted into sterile soils in plastic buckets thereafter. Data collected were subjected to analysis of variance and mean separation. The results obtained showed that peak inhibition of mycelial growth was achieved by 80% garlic extract concentration (76.29% at three days after inoculation). The in vivo study showed that the concentration of garlic extracts as well as the duration of treatment had significant effect on seed germination. Maize seeds dressed with 80% aqueous garlic extract had the least percentage germination, 43.33%, but recorded the least disease incidence and severity at 2 weeks after transplanting. It also had the best yield, fresh weight of cobs, 303.86 g, and the least percentage of kernel infection with F. verticillioides, 15.00%. Garlic extract has potential, as a bio-fungicide, in the management of stalk and ear rot disease of maize.
- Published
- 2020
- Full Text
- View/download PDF
9. Response of selected tomato (Solanum lycopersicum L.) cultivars to on-field biotic stress
- Author
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Ganiyu F. Hassan and Ayodele. M. Ajayi
- Subjects
Horticulture ,biology ,Field (physics) ,Cultivar ,Solanum ,Biotic stress ,biology.organism_classification - Published
- 2019
- Full Text
- View/download PDF
10. Designing a Green Power Delivery System for Base Transceiver Stations in Southwestern Nigeria
- Author
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Joseph Sunday Ojo, Ayodele M. Atoye, and Pius A. Owolawi
- Subjects
business.industry ,Photovoltaic system ,Net present value ,Turbine ,Environmentally friendly ,Environmental friendly ,Automotive engineering ,HOMER-3 ,Renewable energy ,Diesel fuel ,Optimal Performance ,Environmental science ,Renewable Energy ,Diesel generator ,Electrical and Electronic Engineering ,Transceiver ,business ,Green telecommunication - Abstract
In recent times, a green telecommunication system that is regarded as more environmental friendly is clamoring to adequately replace the usage of Diesel Generator only (DG-only) power sources. Alternatively, the diesel generator system can combine with other power supply systems to reduce the effect of greenhouse gases emitted to the environment and to improve power supply reliability. This paper aims at establishing an optimized configuration for typically powering base transceiver stations using remarkable hybrids of Renewable Energy Sources (RESs) with optimal performance in cost consideration, emission, space management and adequate reliability in base-transceiver station area. The optimization was tested on the diverse set of hybrids of RESs for powering BTSs in Southwestern part of Nigeria using Hybrid Optimization of Multiple Electric Renewables (HOMER) micro grid Analysis Tool 3.8.7. The simulated results show that hybrid H2 made of Photovoltaic Cell (PV), Wind Turbine, Diesel Generator, Battery Storage and Converter has the lowest Total Net Present Cost (TNPC) in Lagos, Ogun and Oyo States while hybrid H1 made of PV and DG emerged as the best in Ondo, Ekiti and Osun States. Hybrid H2 with desired characteristics has an average TNPC reduction of 35.01 % over the present system of Diesel Generator-only. Further results revealed precisely that TNPC responds more to change in the global horizontal irradiation than any other uncontrollable variables. These notable findings will be extremely applicable for a cost-effective and environmentally friendly powering schemes that may be efficiently implemented on BTSs in different Southwestern regions of Nigeria.
- Published
- 2019
- Full Text
- View/download PDF
11. Fusarium wilt and Southern Blight Diseases of Tomatoes: Trichoderma spp. as Antagonists of the Causative Organisms
- Author
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Ayodele M. Ajayi, Department of Crop, Soil and Pest Management, Federal University of Technology Akure, Nigeria, Ayodeji, Olusola Ezekiel, M. Ajayi, Ayodele, B. Olufolaji, David, F. Hassan, Ganiyu, Ayodele M. Ajayi, Department of Crop, Soil and Pest Management, Federal University of Technology Akure, Nigeria, Ayodeji, Olusola Ezekiel, M. Ajayi, Ayodele, B. Olufolaji, David, and F. Hassan, Ganiyu
- Abstract
Fusarium wilt (Fusarium oxysporum f. sp. lycopersici) and southern blight (Sclerotium rolfsii) are two of the soil borne diseases limiting tomato cultivation globally and are difficult to manage. This study evaluated biocontrol agents, Trichoderma harzianum and T. viride for antagonistic efficacy against these pathogens in vitro. The dual culture technique was adopted using two approaches; namely, pre-inoculation of Trichoderma spp. into culture medium at 24 and 48 hours ahead of the pathogen and simultaneous inoculation of Trichoderma spp. and pathogen. The Trichoderma spp. were evaluated singly against each pathogen. The sole culture of each pathogen was the control. Each treatment was replicated thrice and laid out in a completely randomized design. Inoculated Petri plates were incubated at 27o C ± 2o C. Data collected were subjected to statistical analysis and mean separation using Minitab software. Results showed that the inhibition of the mycelial growth of both pathogens by the biocontrol agents were days dependent. Furthermore, prophylactic evaluations gave significantly higher inhibition of the mycelial growth of the pathogens as against therapeutic evaluation. Additionally, F. oxysporum was more susceptible to antagonism by both biocontrol agents as higher percentages of mycelial growth inhibition were recorded for it in all treatments. Finally, T. harzianum was a better antagonist of the two pathogens, recording 84.62% and 69.01% inhibition of mycelial growth of F. oxysporum and S. rolfsii, respectively at 9 days after inoculation. Trichoderma spp. maybe exploited as biocontrol agents for the management of these pathogens.
- Published
- 2021
12. First report of Banana bunchy top virus in banana and plantain (Musa spp.) in Angola
- Author
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Lava Kumar, P., Ayodele, M., Oben, T. T., Mahungu, N. M., Beed, F., Coyne, D., Londa, L., Mutunda, M. P., Kiala, D., and Maruthi, M. N.
- Published
- 2009
- Full Text
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13. Chemical and physical hazard profile of ‘Robo’ processing – a street-vended melon snack
- Author
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Sobukola, Olajide P., Awonorin, Olusegun S., Idowu, Ayodele M., and Bamiro, Olukayode F.
- Published
- 2008
14. Designing a Green Power Delivery System for Base Transceiver Stations in Southwestern Nigeria
- Author
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Ojo, Joseph S., primary, Owolawi, Pius A., additional, and Atoye, Ayodele M., additional
- Published
- 2019
- Full Text
- View/download PDF
15. Natural occurrence of Fusarium species and fumonisins in stored cassava chips
- Author
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Onana B, Essono G, Nyegue M, Tchikoua R, Ambang Z, and Ayodele M
- Subjects
Infectious Diseases ,Plant Science ,Microbiology - Published
- 2015
- Full Text
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16. Mapping and Assessment of Healthcare Facilities Using GIS in a Part of Ikorodu Metropolis, Lagos State
- Author
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Effiong, E., Iyiola, O. F., Gbiri, Isaac Adelakun, Oludiji, M. O., Oyebanji, S. T., Ayodele, M. T., Effiong, E., Iyiola, O. F., Gbiri, Isaac Adelakun, Oludiji, M. O., Oyebanji, S. T., and Ayodele, M. T.
- Abstract
The uneven distribution of health care services in Nigeria had been validated the inequalities in the accessibility and the best of fitness care services rendered to citizens. Basic fitness care offerings continue to be a cardinal responsibility of the authorities for the survival of her citizenry. Mostly in the developing country, the accessibility to these health care centres is poorly understood and underserved by the timing populations. there is a need to apprehend the elements that affect or inhibit health care used and what contributed to the use elements in term of distance from residences to the health care amenities and the thickly populace developed round the facilities. This paper focuses on the acceptable evaluation of spatial distribution of health care facilities and proposed for new health centres in some of catchments location that deserves it primarily based on distance and population figures in Ikorodu Local Community Development Area. It was subdivided into Ibese, Ojubode , Local Govt, Police Post, Ebute , Ogoloto , Tos Benson, Ita Elewa, Sambo , Alagbala and Eyita Area with their two land mass for every the catchment area inside the learn about which covered two Ibese Area, Ojubode Area, Local Govt. Area, Police Post Area, Ebute Area, Ogoloto Area, Tos Benson Area, Ita Elewa, Sambo Area, Alagbala Area and Eyita Area covered 128.585 ha, 59.658 ha, 106.793ha, 99.631ha, 140.803ha, 109.485ha, 131.518 ha, 111.625ha, 155.051 ha, 89.698 ha and 112.907 ha. Based on buffer coverage and population used and it was revealed and proposed new healthcare centres for Ojubode, Local Govt, Ibese, part of Eyita, Sambo,Alagbala and Ogoloto areas maps were produced. The useful geodatabase was created for digital healthcare facility mapping for less difficult replace every time it’s necessary.
- Published
- 2019
17. Malaria induced sudden sensorineural hearing loss: a rare presentation
- Author
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Adetola Rachael Adeyeye, Nonso B. Nkemjika, Ayodele M. Akinola, and Adewale D. Agbaakin
- Subjects
Weakness ,medicine.medical_specialty ,business.industry ,Hearing loss ,Malaria fever ,Audiology ,medicine.disease ,Blood film ,Sudden sensorineural hearing loss ,otorhinolaryngologic diseases ,medicine ,Presentation (obstetrics) ,medicine.symptom ,business ,Malaria ,Tinnitus - Abstract
Sudden Hearing loss has been rarely reported as a presenting symptom of malaria fever. It’s even more rare to have a bilateral profound sudden sensorineural hearing loss. A 19 years old female student presented with fever, body weakness, hearing loss with tinnitus. Laboratory investigations done were essentially normal except blood film for malaria parasite which showed a high concentration of the parasite in blood on both occasions. Otoacoustics emission test was passed bilaterally while auditory steady state response showed profound hearing loss bilaterally. Normal hearing was restored within 48 hrs of commencement of anti-malaria drugs and low dose steroids.
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- 2019
- Full Text
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18. Perception and acceptance of Universal Neonatal Hearing Screening among pregnant women attending a Nigerian Teaching Hospital
- Author
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Akinola, Ayodele M, primary, Imaralu, John O., additional, Ani, Franklin I., additional, Yahaya, Oluwasegun, additional, Salami, Omotayo, additional, and Adefalujo, Adekunle, additional
- Published
- 2018
- Full Text
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19. Chemical and physical hazard profile of ‘Robo’ processing - a street-vended melon snack
- Author
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Ayodele. M. Idowu, Olukayode. F. Bamiro, Olusegun. S. Awonorin, and Olajide P. Sobukola
- Subjects
Melon ,Physical hazard ,Critical control point ,Vegetable material ,Environmental science ,Food science ,Contamination ,Animal origin ,Industrial and Manufacturing Engineering ,Mineral matter ,Food Science ,Chemical hazard - Abstract
Summary A study was carried out on the processing of a locally produced ‘robo’ from melon seeds in the Abeokuta metropolis in order to identify potential hazards and critical control points associated with its production and the measures to be adopted for the control of associated hazards. Samples collected along processing lines were subjected to physical and chemical hazard analysis. The results of the analysis showed that the samples were contaminated with the following hazards: mineral matter, tramp metal, extraneous vegetable material and matter of animal origin, as well as lead, cadmium, arsenic and tin (0.33 ± 03, 1.36 ± 0.02, 0.34 ± 0.00 and 1.24 ± 0.03 mg kg−1, respectively) which were still higher than the acceptable limits (0.1 mg kg−1).
- Published
- 2008
- Full Text
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20. Farmers’ perceptions of practices and constraints in cassava (Manihot esculenta Crantz) chips production in rural Cameroon
- Author
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Essono, G, Ayodele, M, Foko, J, Akoa, A, Gockowski, J, Ambang, Z, Bell, JM, and Bekolo, N
- Subjects
Survey, production practices, pests and diseases, lack of the market, safety and hygiene - Abstract
A survey aimed at collecting information on practices and constraints in the production of cassava (Manihot esculenta Crantz) chips, a transformed cassava product obtained through fermentation anddrying of its fresh roots was carried out in 45 villages located in three geographical regions (Yaoundé, Mbalmayo, and Ebolowa) of the humid forest zone of Cameroon. A structured questionnaire to interviewfarmers was employed. Out of 225 farmers sampled, 212 (94%) relying on chips as food and source of income were women. Overall, 51% of all farmers marketed chips locally. Three distinct forms of chipssuch as broken pulp (62%), balls (25%), and pellets (13%) were cited as being locally produced by farmers. These were obtained either through air fermentation (cassava pellets), or submergedfermentation (broken pulps and balls), using starters or fermenting agents (31% of responses) or without using them (69%). Chips were mainly home-stored in jute and or/plastic bags (43% ofresponses), open or closed containers (36%), or on devices hanging over the fireplace (21% of responses) for as long as 180 days. Dark spots or discolouration occurring as a result of chips damagewere reported by the majority of respondents (82%) as frequent on cassava chips. These were related to insufficient drying (42%), the use of infected cassava roots by plant pathogenic microbes from thefields (12%), or too long drying of chips under sun light (11% of responses). To avoid dark spots and/or discolouration, 112 farmers out of a total of 185 who were aware about chips damage, practiced sundrying, and 21% of this total dried their chips over the fireplace to control chips damage. Pests and diseases problems (47% of responses), mainly related to the incidence of Stictococcus vayssiereiRichard (Homoptera: Stictococcidae) and lack of market (26%) were cited by farmers as the most important constraints in cassava chips production. From the results obtained, this study outlined thatthe potential utilization of cassava and its derived products for industrial purposes is not yet exploited in the locations investigated. Additionally, the study also raised concerns about the safety and hygiene associated with traditionally processed and stored cassava chips in the investigated areas.
- Published
- 2010
21. Allelopathic potential of some biocontrol agents for the control of fungal rot of yellow yam (Dioscorea cayenensis Lam)
- Author
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Dania, V. O., primary, Fadina, O. O., additional, Ayodele, M., additional, and Lava, Kumar, P., additional
- Published
- 2015
- Full Text
- View/download PDF
22. Virulence and adhesive properties of serotypes A and B of Candida albicans isolated from paediatric burn patients
- Author
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R. J. Yancey, M. J. Kennedy, Alice N. Neely, P. A. Volz, and Ayodele M. Johnson
- Subjects
Microbiology (medical) ,Serotype ,Virulence ,Microbiology ,Bacterial Adhesion ,Pathogenesis ,Mice ,Candida albicans ,medicine ,Animals ,Humans ,Child ,Feces ,Mycosis ,biology ,Infant, Newborn ,Infant ,General Medicine ,Fungi imperfecti ,medicine.disease ,biology.organism_classification ,Chemically defined medium ,Child, Preschool ,Female ,Burns - Abstract
The virulence and adhesive properties of 50 isolates of Candida albicans serotypes A and B collected over 6 years from 48 paediatric burn patients were examined to provide more detailed information about candidal pathogenesis in burn patients and to examine the relevance of the commonly used epithelial cell adhesion assay for determining fungal virulence. The isolates represented a fair distribution of serotypes (29 isolates were serotype A and 21 isolates were serotype B) and a total of 28 serotype-biotype combinations were found; 32% of the serotype-biotype combinations appeared only once, while 44% of the isolates showed similar biotype tests for two of three digits. Adhesion of the isolates to plastic and to buccal epithelial cells (BECs) was examined and compared after growth in a chemically defined medium. There were significant differences in the adhesion of individual isolates to plastic or BECs, but no correlation was found between biotype and adhesiveness. Serotype B isolates were found to be more adhesive to BECs (p less than 0.05) but not to plastic. There was no apparent correlation between candidal adhesiveness and site of isolation from these patients (autografts, blood, faeces, throat swabs, tracheal aspirates, wounds and intravenous catheters), although isolates from catheters were generally less adhesive to epithelial cells. Virulence in a systemic infection mouse model revealed that there were significant differences in virulence between isolates, but no correlation was found between virulence and the biotype, serotype or site of isolation. Similarly, no correlation was found between virulence and adhesiveness or cell-surface hydrophobicity.(ABSTRACT TRUNCATED AT 250 WORDS)
- Published
- 1992
- Full Text
- View/download PDF
23. Novel Method To Identify Source-Associated Phylogenetic Clustering Shows that Listeria monocytogenes Includes Niche-Adapted Clonal Groups with Distinct Ecological Preferences
- Author
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Nightingale, K. K., Lyles, K., Ayodele, M., Jalan, P., Nielsen, Rasmus, Wiedmann, M., Nightingale, K. K., Lyles, K., Ayodele, M., Jalan, P., Nielsen, Rasmus, and Wiedmann, M.
- Abstract
Udgivelsesdato: October 2006, While phylogenetic and cluster analyses are often used to define clonal groups within bacterial species, the identification of clonal groups that are associated with specific ecological niches or host species remains a challenge. We used Listeria monocytogenes, which causes invasive disease in humans and different animal species and which can be isolated from a number of environments including food, as a model organism to develop and implement a two-step statistical approach to the identification of phylogenetic clades that are significantly associated with different source populations, including humans, animals, and food. If the null hypothesis that the genetic distances for isolates within and between source populations are identical can be rejected (SourceCluster test), then particular clades in the phylogenetic tree with significant overrepresentation of sequences from a given source population are identified (TreeStats test). Analysis of sequence data for 120 L. monocytogenes isolates revealed evidence of clustering between isolates from the same source, based on the phylogenies inferred from actA and inlA (P = 0.02 and P = 0.07, respectively; SourceCluster test). Overall, the TreeStats test identified 10 clades with significant (P < 0.05) or marginally significant (P < 0.10) associations with defined sources, including human-, animal-, and food-associated clusters. Epidemiological and virulence phenotype data supported the fact that the source-associated clonal groups identified here are biologically valid. Overall, our data show that (i) the SourceCluster and TreeStats tests can identify biologically meaningful s
- Published
- 2006
24. First report ofBanana bunchy top virusin banana and plantain (Musaspp.) in Angola
- Author
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Lava Kumar, P., primary, Ayodele, M., additional, Oben, T. T., additional, Mahungu, N. M., additional, Beed, F., additional, Coyne, D., additional, Londa, L., additional, Mutunda, M. P., additional, Kiala, D., additional, and Maruthi, M. N., additional
- Published
- 2009
- Full Text
- View/download PDF
25. Novel Method To Identify Source-Associated Phylogenetic Clustering Shows that Listeria monocytogenes Includes Niche-Adapted Clonal Groups with Distinct Ecological Preferences
- Author
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Nightingale, K. K., primary, Lyles, K., additional, Ayodele, M., additional, Jalan, P., additional, Nielsen, R., additional, and Wiedmann, M., additional
- Published
- 2006
- Full Text
- View/download PDF
26. Developing new plantain varieties for Africa
- Author
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Ortiz, R., Vuylsteke, D. R., Ferris, R. S. B., Okoro, J. U., N'Guessan, A., Hemeng, O. B., Yeboah, D. K., Afreh-Nuamah, K., Ahiekpor, E. K. S., Foure, E., Adelaja, B. A., Ayodele, M., Arene, O. B., Ikiediugwu, F. E. O., Agbor, A. N., Nwogu, A. N., Okoro, E., Kayode, G., Ipinmoye, I. K., Akele, S., Lawrence, A., Ortiz, R., Vuylsteke, D. R., Ferris, R. S. B., Okoro, J. U., N'Guessan, A., Hemeng, O. B., Yeboah, D. K., Afreh-Nuamah, K., Ahiekpor, E. K. S., Foure, E., Adelaja, B. A., Ayodele, M., Arene, O. B., Ikiediugwu, F. E. O., Agbor, A. N., Nwogu, A. N., Okoro, E., Kayode, G., Ipinmoye, I. K., Akele, S., and Lawrence, A.
- Published
- 1997
27. Novel Method To Identify Source-Associated Phylogenetic Clustering Shows that Listeria monocytogenesIncludes Niche-Adapted Clonal Groups with Distinct Ecological Preferences
- Author
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Nightingale, K. K., Lyles, K., Ayodele, M., Jalan, P., Nielsen, R., and Wiedmann, M.
- Abstract
ABSTRACTWhile phylogenetic and cluster analyses are often used to define clonal groups within bacterial species, the identification of clonal groups that are associated with specific ecological niches or host species remains a challenge. We used Listeria monocytogenes, which causes invasive disease in humans and different animal species and which can be isolated from a number of environments including food, as a model organism to develop and implement a two-step statistical approach to the identification of phylogenetic clades that are significantly associated with different source populations, including humans, animals, and food. If the null hypothesis that the genetic distances for isolates within and between source populations are identical can be rejected (SourceCluster test), then particular clades in the phylogenetic tree with significant overrepresentation of sequences from a given source population are identified (TreeStats test). Analysis of sequence data for 120 L. monocytogenesisolates revealed evidence of clustering between isolates from the same source, based on the phylogenies inferred from actAand inlA(P= 0.02 and P= 0.07, respectively; SourceCluster test). Overall, the TreeStats test identified 10 clades with significant (P< 0.05) or marginally significant (P< 0.10) associations with defined sources, including human-, animal-, and food-associated clusters. Epidemiological and virulence phenotype data supported the fact that the source-associated clonal groups identified here are biologically valid. Overall, our data show that (i) the SourceCluster and TreeStats tests can identify biologically meaningful source-associated phylogenetic clusters and (ii) L. monocytogenesincludes clonal groups that have adapted to infect specific host species or colonize nonhost environments.
- Published
- 2006
- Full Text
- View/download PDF
28. Intrathecal Methotrexate Toxicity Resulting in Brain Death due to Generalized Cerebral Edema Case Report.
- Author
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Pang H, Chan JL, Bannykh SI, Gezalian M, Lahiri S, Toossi S, and Ayodele M
- Abstract
Intrathecal methotrexate (IT MTX) resulting in severe adverse events including life-threatening cerebral edema is not well described. We report a rare case of death in a 37-year-old BRCA1+ woman with metastatic triple-negative breast cancer status post mastectomy following administration of IT MTX for leptomeningeal carcinomatosis. Within the 24 hours after intraoperative IT MTX delivery, she developed neurologically devastating diffuse cerebral edema leading to uncal and cerebellar tonsillar herniation. This case report highlights a rare but devastating side effect of IT MTX., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2022.)
- Published
- 2022
- Full Text
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29. Antibody and cellular immune responses following dual COVID-19 vaccination within infection-naive residents of long-term care facilities: an observational cohort study.
- Author
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Tut G, Lancaster T, Sylla P, Butler MS, Kaur N, Spalkova E, Bentley C, Amin U, Jadir A, Hulme S, Ayodele M, Bone D, Tut E, Bruton R, Krutikov M, Giddings R, Shrotri M, Azmi B, Fuller C, Baynton V, Irwin-Singer A, Hayward A, Copas A, Shallcross L, and Moss P
- Subjects
- Aged, 80 and over, Antibodies, Viral, COVID-19 Vaccines, Humans, Immunity, Cellular, Long-Term Care, Middle Aged, SARS-CoV-2, Vaccination, COVID-19, Vaccines
- Abstract
Background: Older age and frailty are risk factors for poor clinical outcomes following SARS-CoV-2 infection. As such, COVID-19 vaccination has been prioritised for individuals with these factors, but there is concern that immune responses might be impaired due to age-related immune dysregulation and comorbidity. We aimed to study humoral and cellular responses to COVID-19 vaccines in residents of long-term care facilities (LTCFs)., Methods: In this observational cohort study, we assessed antibody and cellular immune responses following COVID-19 vaccination in members of staff and residents at 74 LTCFs across the UK. Staff and residents were eligible for inclusion if it was possible to link them to a pseudo-identifier in the COVID-19 datastore, if they had received two vaccine doses, and if they had given a blood sample 6 days after vaccination at the earliest. There were no comorbidity exclusion criteria. Participants were stratified by age (<65 years or ≥65 years) and infection status (previous SARS-CoV-2 infection [infection-primed group] or SARS-CoV-2 naive [infection-naive group]). Anticoagulated edetic acid (EDTA) blood samples were assessed and humoral and cellular responses were quantified., Findings: Between Dec 11, 2020, and June 27, 2021, blood samples were taken from 220 people younger than 65 years (median age 51 years [IQR 39-61]; 103 [47%] had previously had a SARS-CoV-2 infection) and 268 people aged 65 years or older of LTCFs (median age 87 years [80-92]; 144 [43%] had a previous SARS-CoV-2 infection). Samples were taken a median of 82 days (IQR 72-100) after the second vaccination. Antibody responses following dual vaccination were strong and equivalent between participants younger then 65 years and those aged 65 years and older in the infection-primed group (median 125 285 Au/mL [1128 BAU/mL] for <65 year olds vs 157 979 Au/mL [1423 BAU/mL] for ≥65 year olds; p=0·47). The antibody response was reduced by 2·4-times (467 BAU/mL; p≤0·0001) in infection-naive people younger than 65 years and 8·1-times (174 BAU/mL; p≤0·0001) in infection-naive residents compared with their infection-primed counterparts. Antibody response was 2·6-times lower in infection-naive residents than in infection-naive people younger than 65 years (p=0·0006). Impaired neutralisation of delta (1.617.2) variant spike binding was also apparent in infection-naive people younger than 65 years and in those aged 65 years and older. Spike-specific T-cell responses were also significantly enhanced in the infection-primed group. Infection-naive people aged 65 years and older (203 SFU per million [IQR 89-374]) had a 52% lower T-cell response compared with infection-naive people younger than 65 years (85 SFU per million [30-206]; p≤0·0001). Post-vaccine spike-specific CD4 T-cell responses displayed single or dual production of IFN-γ and IL-2 were similar across infection status groups, whereas the infection-primed group had an extended functional profile with TNFα and CXCL10 production., Interpretation: These data reveal suboptimal post-vaccine immune responses within infection-naive residents of LTCFs, and they suggest the need for optimisation of immune protection through the use of booster vaccination., Funding: UK Government Department of Health and Social Care., Competing Interests: LS reports grants from the Department of Health and Social Care during the study and is a member of the Social Care Working Group, which reports to the Scientific Advisory Group for Emergencies. AH is a member of the New and Emerging Respiratory Virus Threats Advisory Group at the Department of Health. All other authors declare no competing interests., (© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.)
- Published
- 2022
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30. mRNA or ChAd0x1 COVID-19 Vaccination of Adolescents Induces Robust Antibody and Cellular Responses With Continued Recognition of Omicron Following mRNA-1273.
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Dowell AC, Powell AA, Davis C, Scott S, Logan N, Willett BJ, Bruton R, Ayodele M, Jinks E, Gunn J, Spalkova E, Sylla P, Nicol SM, Zuo J, Ireland G, Okike I, Baawuah F, Beckmann J, Ahmad S, Garstang J, Brent AJ, Brent B, White M, Collins A, Davis F, Lim M, Cohen J, Kenny J, Linley E, Poh J, Amirthalingam G, Brown K, Ramsay ME, Azad R, Wright J, Waiblinger D, Moss P, and Ladhani SN
- Subjects
- 2019-nCoV Vaccine mRNA-1273, Adolescent, Adult, Antibodies, Viral, BNT162 Vaccine, Child, Humans, RNA, Messenger, SARS-CoV-2, Vaccination, Vaccines, Synthetic, mRNA Vaccines, COVID-19 prevention & control, COVID-19 Vaccines adverse effects
- Abstract
Children and adolescents generally experience mild COVID-19. However, those with underlying physical health conditions are at a significantly increased risk of severe disease. Here, we present a comprehensive analysis of antibody and cellular responses in adolescents with severe neuro-disabilities who received COVID-19 vaccination with either ChAdOx1 (n=6) or an mRNA vaccine (mRNA-1273, n=8, BNT162b2, n=1). Strong immune responses were observed after vaccination and antibody levels and neutralisation titres were both higher after two doses. Both measures were also higher after mRNA vaccination and were further enhanced by prior natural infection where one vaccine dose was sufficient to generate peak antibody response. Robust T-cell responses were generated after dual vaccination and were also higher following mRNA vaccination. Early T-cells were characterised by a dominant effector-memory CD4+ T-cell population with a type-1 cytokine signature with additional production of IL-10. Antibody levels were well-maintained for at least 3 months after vaccination and 3 of 4 donors showed measurable neutralisation titres against the Omicron variant. T-cell responses also remained robust, with generation of a central/stem cell memory pool and showed strong reactivity against Omicron spike. These data demonstrate that COVID-19 vaccines display strong immunogenicity in adolescents and that dual vaccination, or single vaccination following prior infection, generate higher immune responses than seen after natural infection and develop activity against Omicron. Initial evidence suggests that mRNA vaccination elicits stronger immune responses than adenoviral delivery, although the latter is also higher than seen in adult populations. COVID-19 vaccines are therefore highly immunogenic in high-risk adolescents and dual vaccination might be able to provide relative protection against the Omicron variant that is currently globally dominant., Competing Interests: MR received funding for the COV-BOOST trial under contract via University Hospital Southampton NHS Foundation Trust, Funded by the UK NIHR/Vaccine Task Force (NIHR203292). Post-marketing surveillance reports on pneumococcal and meningococcal infection have been provided to vaccine manufacturers for which a cost recovery charge was made to GSK and Pfizer. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Dowell, Powell, Davis, Scott, Logan, Willett, Bruton, Ayodele, Jinks, Gunn, Spalkova, Sylla, Nicol, Zuo, Ireland, Okike, Baawuah, Beckmann, Ahmad, Garstang, Brent, Brent, White, Collins, Davis, Lim, Cohen, Kenny, Linley, Poh, Amirthalingam, Brown, Ramsay, Azad, Wright, Waiblinger, Moss and Ladhani.)
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- 2022
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31. Profile of humoral and cellular immune responses to single doses of BNT162b2 or ChAdOx1 nCoV-19 vaccines in residents and staff within residential care homes (VIVALDI): an observational study.
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Tut G, Lancaster T, Krutikov M, Sylla P, Bone D, Kaur N, Spalkova E, Bentley C, Amin U, Jadir AT, Hulme S, Butler MS, Ayodele M, Bruton R, Shrotri M, Azmi B, Fuller C, Irwin-Singer A, Hayward A, Copas A, Shallcross L, and Moss P
- Subjects
- Adult, Angiotensin-Converting Enzyme 2, BNT162 Vaccine, COVID-19 Vaccines, ChAdOx1 nCoV-19, Humans, Immunity, Cellular, Middle Aged, SARS-CoV-2, Spike Glycoprotein, Coronavirus, COVID-19, Vaccines
- Abstract
Background: Residents of long-term care facilities (LTCFs) have been prioritised for COVID-19 vaccination because of the high COVID-19 mortality in this population. Several countries have implemented an extended interval of up to 12 weeks between the first and second vaccine doses to increase population coverage of single-dose vaccination. We aimed to assess the magnitude and quality of adaptive immune responses following a single dose of COVID-19 vaccine in LTCF residents and staff., Methods: From the LTCFs participating in the ongoing VIVALDI study (ISRCTN14447421), staff and residents who had received a first dose of COVID-19 vaccine (BNT162b2 [tozinameran] or ChAdOx1 nCoV-19), had pre-vaccination and post-vaccination blood samples (collected between Dec 11, 2020, and Feb 16, 2021), and could be linked to a pseudoidentifier in the COVID-19 Data Store were included in our cohort. Past infection with SARS-CoV-2 was defined on the basis of nucleocapsid-specific IgG antibodies being detected through a semiquantitative immunoassay, and participants who tested positive on this assay after but not before vaccination were excluded from the study. Processed blood samples were assessed for spike-specific immune responses, including spike-specific IgG antibody titres, T-cell responses to spike protein peptide mixes, and inhibition of ACE2 binding by spike protein from four variants of SARS-CoV-2 (the original strain as well as the B.1.1.7, B.1.351, and P.1 variants). Responses before and after vaccination were compared on the basis of age, previous infection status, role (staff or resident), and time since vaccination., Findings: Our cohort comprised 124 participants from 14 LTCFs: 89 (72%) staff (median age 48 years [IQR 35·5-56]) and 35 (28%) residents (87 years [77-90]). Blood samples were collected a median 40 days (IQR 25-47; range 6-52) after vaccination. 30 (24%) participants (18 [20%] staff and 12 [34%] residents) had serological evidence of previous SARS-CoV-2 infection. All participants with previous infection had high antibody titres following vaccination that were independent of age ( r
s =0·076, p=0·70). In participants without evidence of previous infection, titres were negatively correlated with age ( rs =-0·434, p<0·0001) and were 8·2-times lower in residents than in staff. This effect appeared to result from a kinetic delay antibody generation in older infection-naive participants, with the negative age correlation disappearing only in samples taken more than 42 days post-vaccination ( rs =-0·207, p=0·20; n=40), in contrast to samples taken after 0-21 days ( rs =-0·774, p=0·0043; n=12) or 22-42 days ( rs =-0·437, p=0·0034; n=43). Spike-specific cellular responses were similar between older and younger participants. In infection-naive participants, antibody inhibition of ACE2 binding by spike protein from the original SARS-CoV-2 strain was negatively correlated with age ( rs =-0·439, p<0·0001), and was significantly lower against spike protein from the B.1.351 variant (median inhibition 31% [14-100], p=0·010) and the P.1 variant (23% [14-97], p<0·0001) than against the original strain (58% [27-100]). By contrast, a single dose of vaccine resulted in around 100% inhibition of the spike-ACE2 interaction against all variants in people with a history of infection., Interpretation: History of SARS-CoV-2 infection impacts the magnitude and quality of antibody response after a single dose of COVID-19 vaccine in LTCF residents. Residents who are infection-naive have delayed antibody responses to the first dose of vaccine and should be considered for an early second dose where possible., Funding: UK Government Department of Health and Social Care., Competing Interests: AI-S is an employee of the UK Department of Health and Social Care, which funded the study. AH is a member of the New and Emerging Respiratory Virus Threats Advisory Group at the Department of Health. AC reports grants from the UK Department of Health and Social Care during the conduct of the study. LS reports grants from the UK Department of Health and Social Care during the conduct of the study and is a member of the Social Care Working Group, which reports to the Scientific Advisory Group for Emergencies. All other authors declare no competing interests., (© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 license.)- Published
- 2021
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32. National Institutes of Health StrokeNet Training Core.
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Vahidy FS, Sozener CB, Meeks JR, Chhatbar PY, Ramos-Estebanez C, Ayodele M, Richards RJ, Sharma R, Wilbrand SM, Prabhakaran S, Bregman BS, Adams HP Jr, Jordan LC, Liebeskind DS, Tirschwell D, Janis LS, Marshall RS, and Kleindorfer D
- Subjects
- Biomedical Research economics, Humans, United States, Biomedical Research education, Fellowships and Scholarships, Financing, Organized, Mentors, National Institutes of Health (U.S.), Stroke
- Abstract
Background and Purpose- The National Institutes of Health (NIH) StrokeNet provides a nationwide infrastructure to advance stroke research. Capitalizing on this unique opportunity, the NIH StrokeNet Training Core (NSTC) was established with the overarching goal of enhancing the professional development of a diverse spectrum of professionals who are embedded in the stroke clinical trials network of the NIH StrokeNet. Methods- This special report provides a descriptive account of the rationale, organization, and activities of the NSTC since its inception in 2013. Current processes and their evolution over time for facilitating training of NIH StrokeNet trainees have been highlighted. Data collected for monitoring training are summarized. Outcomes data (publications and grants) collected by NSTC was supplemented by publicly available resources. Results- The NSTC comprises of cross-network faculty, trainees, and education coordinators. It helps in the development and monitoring of training programs and organizes educational and career development activities. Trainees are provided directed guidance towards their mandated research projects, including opportunities to present at the International Stroke Conference. The committee has focused on developing sustainable models of peer-to-peer interaction and cross-institutional mentorships. A total of 124 professionals (43.7% female, 10.5% underrepresented minorities) have completed training between 2013 and 2018, of whom 55% were clinical vascular neurologists. Of the total, 85% transitioned to a formal academic position and 95% were involved in stroke research post-training. Altogether, 1659 indexed publications have been authored or co-authored by NIH StrokeNet Trainees, of which 58% were published during or after their training years. Based on data from 109 trainees, 33% had submitted 72 grant proposals as principal or co-principal investigators of which 22.2% proposals have been funded. Conclusions- NSTC has provided a foundation to foster nationwide training in stroke research. Our data demonstrate strong contribution of trainees towards academic scholarship. Continued innovation in educational methodologies is required to adapt to unique training opportunities such as the NIH StrokeNet.
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- 2020
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33. An Unusual Etiology of Acute Spontaneous Intracerebral Hemorrhage.
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Sivasankar C, White K, and Ayodele M
- Abstract
Competing Interests: Declaration of Conflicting Interests: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
- Published
- 2019
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34. Disparities and Trends in Door-to-Needle Time: The FL-PR CReSD Study (Florida-Puerto Rico Collaboration to Reduce Stroke Disparities).
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Oluwole SA, Wang K, Dong C, Ciliberti-Vargas MA, Gutierrez CM, Yi L, Romano JG, Perez E, Tyson BA, Ayodele M, Asdaghi N, Gardener H, Rose DZ, Garcia EJ, Zevallos JC, Foster D, Robichaux M, Waddy SP, Sacco RL, and Rundek T
- Subjects
- Administration, Intravenous, Aged, Aged, 80 and over, Black People ethnology, Cooperative Behavior, Female, Fibrinolytic Agents administration & dosage, Florida ethnology, Healthcare Disparities standards, Humans, Male, Middle Aged, Needles, Prospective Studies, Puerto Rico ethnology, Registries, Retrospective Studies, Sex Factors, Stroke diagnosis, Thrombolytic Therapy methods, Time-to-Treatment standards, White People ethnology, Black or African American, Healthcare Disparities trends, Stroke drug therapy, Stroke ethnology, Thrombolytic Therapy trends, Time-to-Treatment trends, Tissue Plasminogen Activator administration & dosage
- Abstract
Background and Purpose: In the United States, about half of acute ischemic stroke patients treated with tPA (tissue-type plasminogen activator) receive treatment within 60 minutes of hospital arrival. We aimed to determine the proportion of patients receiving tPA within 60 minutes (door-to-needle time [DTNT] ≤60) and 45 minutes (DTNT ≤45) of hospital arrival by race/ethnicity and sex and to identify temporal trends in DTNT ≤60 and DTNT ≤45., Methods: Among 65 654 acute ischemic stroke admissions in the National Institute of Neurological Disorders and Stroke-funded FL-PR CReSD study (Florida-Puerto Rico Collaboration to Reduce Stroke Disparities) from 2010 to 2015, we included 6181 intravenous tPA-treated cases (9.4%). Generalized estimating equations were used to determine predictors of DTNT ≤60 and DTNT ≤45., Results: DTNT ≤60 was achieved in 42% and DTNT ≤45 in 18% of cases. After adjustment, women less likely received DTNT ≤60 (odds ratio, 0.81; 95% confidence interval, 0.72-0.92) and DTNT ≤45 (odds ratio, 0.73; 95% confidence interval, 0.57-0.93). Compared with Whites, Blacks less likely had DTNT ≤45 during off hours (odds ratio, 0.68; 95% confidence interval, 0.47-0.98). Achievement of DTNT ≤60 and DTNT ≤45 was highest in South Florida (50%, 23%) and lowest in West Central Florida (28%, 11%)., Conclusions: In the FL-PR CReSD, achievement of DTNT ≤60 and DTNT ≤45 remains low. Compared with Whites, Blacks less likely receive tPA treatment within 45 minutes during off hours. Treatment within 60 and 45 minutes is lower in women compared with men and lowest in West Central Florida compared with other Florida regions and Puerto Rico. Further research is needed to identify reasons for delayed thrombolytic treatment in women and Blacks and factors contributing to regional disparities in DTNT., (© 2017 American Heart Association, Inc.)
- Published
- 2017
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35. Efficacy of Oryza sativa husk and Quercus phillyraeoides extracts for the in vitro and in vivo control of fungal rot disease of white yam (Dioscorea rotundata Poir).
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Dania VO, Fadina OO, Ayodele M, and Kumar PL
- Abstract
Tuber rot disease is a major constraint to white yam (Dioscorea rotundata) production, accounting for 50-60% of annual yield losses in Nigeria. The main method of control using synthetic fungicides is being discouraged due to human and environmental health hazards. The potential of Oryza sativa husk (OSH) and Quercus phillyraeoides (QP) extracts for the in vitro and in vivo control of six virulent rot-causing fungal pathogens, Lasiodiplodia theobromae, Aspergillus niger, Rhizoctonia solani, Penicillium oxalicum, Sclerotium rolfsii, and Fusarium oxysporum was evaluated, using five different extract concentrations of 0.5%, 1.0%, 1.5%, 2.5%, and 3.5% w/v. These fungi were isolated from rotted tubers of D. rotundata, across three agroecological zones in Nigeria-the Humid rainforest, Derived savanna, and southern Guinea savanna. All treatments were subjected to three methods of inoculation 48 hours before the application of both extracts and stored at 28 ± 2°C for 6 months. Radial mycelial growth of the test pathogens was effectively inhibited at concentrations ≤ 3.5% w/v in vitro for both OSH and QP extracts. Rotting was significantly reduced (P ≤ 0.05) to between 0 to 18.8% and 0% to 20.9% for OSH and QP extracts respectively. The extracts significantly (P ≤ 0.05) inhibited percent rot of the test pathogens at 3.5% concentration w/v in vivo. Rot incidence was, however, lower in replicate tubers that were inoculated, treated with extracts and exposed than treatments that were covered. Phytochemical analysis of OSH and QP extracts revealed the presence of secondary metabolites such as alkaloids, flavonoids, saponins, tannins, ferulic acid, phlobatanins, Terpenoids, phenols, anthraquinone and pyroligneous acid. The efficacy of both extracts in reducing rot in this study recommends their development as prospective biopesticide formulation and use in the management of post-harvest rot of yam tubers.
- Published
- 2014
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36. Stress granules and processing bodies are dynamically linked sites of mRNP remodeling.
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Kedersha N, Stoecklin G, Ayodele M, Yacono P, Lykke-Andersen J, Fritzler MJ, Scheuner D, Kaufman RJ, Golan DE, and Anderson P
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- Animals, COS Cells, Chlorocebus aethiops, Cytoplasmic Granules genetics, Cytoplasmic Granules ultrastructure, Eukaryotic Initiation Factor-2 genetics, HeLa Cells, Humans, Polyribosomes genetics, Polyribosomes metabolism, Protein Biosynthesis genetics, Protein Transport genetics, RNA Processing, Post-Transcriptional genetics, RNA, Messenger genetics, Ribonucleoproteins genetics, Stress, Physiological genetics, Transcription Factors genetics, Transcription Factors metabolism, Cytoplasmic Granules metabolism, Eukaryotic Initiation Factor-2 metabolism, RNA Stability genetics, RNA, Messenger metabolism, Ribonucleoproteins metabolism, Stress, Physiological metabolism
- Abstract
Stress granules (SGs) are cytoplasmic aggregates of stalled translational preinitiation complexes that accumulate during stress. GW bodies/processing bodies (PBs) are distinct cytoplasmic sites of mRNA degradation. In this study, we show that SGs and PBs are spatially, compositionally, and functionally linked. SGs and PBs are induced by stress, but SG assembly requires eIF2alpha phosphorylation, whereas PB assembly does not. They are also dispersed by inhibitors of translational elongation and share several protein components, including Fas-activated serine/threonine phosphoprotein, XRN1, eIF4E, and tristetraprolin (TTP). In contrast, eIF3, G3BP, eIF4G, and PABP-1 are restricted to SGs, whereas DCP1a and 2 are confined to PBs. SGs and PBs also can harbor the same species of mRNA and physically associate with one another in vivo, an interaction that is promoted by the related mRNA decay factors TTP and BRF1. We propose that mRNA released from disassembled polysomes is sorted and remodeled at SGs, from which selected transcripts are delivered to PBs for degradation.
- Published
- 2005
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37. Stress granule assembly is mediated by prion-like aggregation of TIA-1.
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Gilks N, Kedersha N, Ayodele M, Shen L, Stoecklin G, Dember LM, and Anderson P
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- Amino Acid Sequence, Animals, COS Cells, Chlorocebus aethiops, Gene Expression Regulation, HSP70 Heat-Shock Proteins genetics, HSP70 Heat-Shock Proteins metabolism, Humans, Mice, Microscopy, Electron, Transmission, Molecular Sequence Data, Peptide Hydrolases metabolism, Protein Binding, RNA-Binding Proteins genetics, Ribosomes metabolism, Solubility, Cytoplasmic Granules metabolism, Inclusion Bodies metabolism, Prions chemistry, RNA-Binding Proteins chemistry, RNA-Binding Proteins metabolism
- Abstract
TIA-1 is an RNA binding protein that promotes the assembly of stress granules (SGs), discrete cytoplasmic inclusions into which stalled translation initiation complexes are dynamically recruited in cells subjected to environmental stress. The RNA recognition motifs of TIA-1 are linked to a glutamine-rich prion-related domain (PRD). Truncation mutants lacking the PRD domain do not induce spontaneous SGs and are not recruited to arsenite-induced SGs, whereas the PRD forms aggregates that are recruited to SGs in low-level-expressing cells but prevent SG assembly in high-level-expressing cells. The PRD of TIA-1 exhibits many characteristics of prions: concentration-dependent aggregation that is inhibited by the molecular chaperone heat shock protein (HSP)70; resistance to protease digestion; sequestration of HSP27, HSP40, and HSP70; and induction of HSP70, a feedback regulator of PRD disaggregation. Substitution of the PRD with the aggregation domain of a yeast prion, SUP35-NM, reconstitutes SG assembly, confirming that a prion domain can mediate the assembly of SGs. Mouse embryomic fibroblasts (MEFs) lacking TIA-1 exhibit impaired ability to form SGs, although they exhibit normal phosphorylation of eukaryotic initiation factor (eIF)2alpha in response to arsenite. Our results reveal that prion-like aggregation of TIA-1 regulates SG formation downstream of eIF2alpha phosphorylation in response to stress.
- Published
- 2004
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