73 research outputs found
Effect Of Aqueous Extract of Cola Nitida (Kola Nut) On Haematological and Plasma Biochemical Parameters in Male Albino Rats
Abstract: Cola nitida (Kola nut) is a caffeine-containing nut native to tropical Nort
Critical Node Detection for Voltage Collapse Mitigation in Modern Power Systems: A Network Topological-Based Approach
Quick detection of critical nodes has become a great concern to most investors and utilities recently due to its influence on prevention of the frequent occurrence of voltage collapse within a power network. This paper, therefore presents an option for detecting critical nodes, an approach which is based on the network topological characteristics of power networks. The mathematical formulations of the approach from the basic circuit theory laws were revisited. A Normalized Eigenvalue (NEV) index using eigenvalue and eigenvector analyses was then developed using MATLAB 2019b as the simulation tool. A simple 10-bus network was used to test the effectiveness of the NEV index method suggested in this paper. The NEV for all the network buses was determined and ranked in decreasing value of NEV to measure the criticality and vulnerability of each load node to voltage collapse within the system. Buses 6 had the highest value of NEV index (1.00) while bus 4 had the lowest NEV index (0.00) value. This suggested that there is a possibility of occurrence of over-voltage at bus 6 and undervoltage at bus 4. Therefore, buses 4 and 6 were identified as the critical buses, where placement of the reactive power support will be most beneficial. The results obtained were compared with those obtained using other methods documented in the literature. The comparison showed the effectiveness of the approach in quick identification of critical parts of the network most especially during critical outages
Molecular Characterization of the Circulating Strains of Vibrio cholerae during 2010 Cholera Outbreak in Nigeria
This study aimed at characterizing the phenotypic and toxigenic status
of circulating strains of cholera during outbreaks in Nigeria,
employing molecular typing techniques. Two hundred and one samples of
rectal swabs, stool, vomitus, water (from the well, borehole, sachet,
stream, and tap) and disinfectants (sodium hypochlorite) were collected
from three states in the country. The samples were inoculated on
thiosulphate-citrate bile salt-sucrose (TCBS), Cary-Blair transport
medium and smeared on glass slides for direct examination. The Vibrio
cholerae isolates were serotyped, biotyped, and characterized using
PCR of the cytotoxin gene A (ctxA), wbeO1, and wbfO139 gene primer. Of
the 201 samples screened, 96 were positive for V. cholerae O1 (48%),
with 69 (72%) positive for ctxA gene. The results from this study
showed that the circulating strains of cholera in Nigeria were of Ogawa
serotype, also observed in other outbreaks in Nigeria (1991, 1992, and
1996). However, the strains were of the Classical biotype and were
mainly (72%) ctxA gene-positive. This current investigation has
confirmed the production of cholera toxin by the circulating strains,
and this could be harnessed for possible cholera vaccine production in
Nigeria
Exploiting antitumor immunity to overcome relapse and improve remission duration
Cancer survivors often relapse due to evolving drug-resistant clones and repopulating tumor stem cells. Our preclinical study demonstrated that terminal cancer patient’s lymphocytes can be converted from tolerant bystanders in vivo into effective cytotoxic T-lymphocytes in vitro killing patient’s own tumor cells containing drug-resistant clones and tumor stem cells. We designed a clinical trial combining peginterferon α-2b with imatinib for treatment of stage III/IV gastrointestinal stromal tumor (GIST) with the rational that peginterferon α-2b serves as danger signals to promote antitumor immunity while imatinib’s effective tumor killing undermines tumor-induced tolerance and supply tumor-specific antigens in vivo without leukopenia, thus allowing for proper dendritic cell and cytotoxic T-lymphocyte differentiation toward Th1 response. Interim analysis of eight patients demonstrated significant induction of IFN-γ-producing-CD8+, -CD4+, -NK cell, and IFN-γ-producing-tumor-infiltrating-lymphocytes, signifying significant Th1 response and NK cell activation. After a median follow-up of 3.6 years, complete response (CR) + partial response (PR) = 100%, overall survival = 100%, one patient died of unrelated illness while in remission, six of seven evaluable patients are either in continuing PR/CR (5 patients) or have progression-free survival (PFS, 1 patient) exceeding the upper limit of the 95% confidence level of the genotype-specific-PFS of the phase III imatinib-monotherapy (CALGB150105/SWOGS0033), demonstrating highly promising clinical outcomes. The current trial is closed in preparation for a larger future trial. We conclude that combination of targeted therapy and immunotherapy is safe and induced significant Th1 response and NK cell activation and demonstrated highly promising clinical efficacy in GIST, thus warranting development in other tumor types
Increased Terpenoid Accumulation in Cotton (Gossypium hirsutum) Foliage is a General Wound Response
The subepidermal pigment glands of cotton accumulate a variety of terpenoid products, including monoterpenes, sesquiterpenes, and terpenoid aldehydes that can act as feeding deterrents against a number of insect herbivore species. We compared the effect of herbivory by Spodoptera littoralis caterpillars, mechanical damage by a fabric pattern wheel, and the application of jasmonic acid on levels of the major representatives of the three structural classes of terpenoids in the leaf foliage of 4-week-old Gossypium hirsutum plants. Terpenoid levels increased successively from control to mechanical damage, herbivory, and jasmonic acid treatments, with E-β-ocimene and heliocide H1 and H4 showing the highest increases, up to 15-fold. Herbivory or mechanical damage to older leaves led to terpenoid increases in younger leaves. Leaf-by-leaf analysis of terpenes and gland density revealed that higher levels of terpenoids were achieved by two mechanisms: (1) increased filling of existing glands with terpenoids and (2) the production of additional glands, which were found to be dependent on damage intensity. As the relative response of individual terpenoids did not differ substantially among herbivore, mechanical damage, and jasmonic acid treatments, the induction of terpenoids in cotton foliage appears to represent a non-specific wound response mediated by jasmonic acid
Anticholinesterase and Antioxidant Activities of Spilanthes filicaulis Whole Plant Extracts for the Management of Alzheimer’s Disease
Background: Spilanthes filicaulis is a tropical herb implicated as a memory enhancer in ethnomedicine. Objective: The study investigated acetyl/butyryl cholinesterase inhibitory and antioxidant activities of different extracts of S. filicaulis whole plant and correlated them to its phytochemical constituents. Methods: The powdered whole plant was successively extracted with n-hexane, ethyl acetate and methanol. Acetyl cholinesterase (AChE) and Butyryl cholinesterase (BuChE) inhibitory activity were evaluated by Ellman colorimetry assay. Antioxidant activity was tested using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing power and nitric oxide scavenging assays. Total phenolic, flavonoid and tannin were estimated using standard methods. Correlation was determined using Quest Graph™ Regression Calculator. Results: Various extracts exhibited concentration-dependent AChE and BuChE inhibitory activity with ethyl acetate extract being the highest with IC50 of 0.77 μg/mL and 0.92 μg/mL for AChE and BuChE respectively. The ethyl acetate extract also showed the highest reducing power when compared with the other extracts. The methanol extract had slightly higher phenolic and flavonoid content and showed the highest DPPH radical scavenging effect. DPPH scavenging, AChE and BuChE inhibition had high correlation with the total flavonoid content with R2 values of 1.00, 0.800 and 0.992 respectively while nitric oxide scavenging had high correlation with phenolics and tannins with R2 = 0.942 and 0.806 respectively. Conclusion: These results show that the extracts of the whole plant of S. filicaulis possess significant AChE/BuChE inhibitory and antioxidant properties, mostly due to its flavonoid content, suggesting the possible use of the plant in neurodegenerative diseases such as AD
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