Path Following by a Quadrotor Using Virtual Target Pursuit Guidance

Quadrotors, being more agile than fixed-wing vehicles, are the ideal candidates for autonomous missions in small, compact spaces. The immense challenge to navigate such environments is fulfilled by the concept of path following. Path following is the method of tracking/tracing a fixed, pre-defined path with minimum position error while exerting the lowest possible control effort. In this work, the missile guidance technique of pure pursuit is adopted and modified for a 3D quadrotor model to follow fixed, compact trajectories. A specialized hardware testing platform is developed to test this algorithm. The results obtained from simulation and flight tests are compared to results from another technique called differential flatness. A small part of this thesis also deals with the stability analysis of the modified 3D pure pursuit algorithm to track trajectories expending lower control effort

Sporadic Medullary Microcarcinoma in a Young Patient - A Rare Case

Sporadic medullary microcarcinoma of thyroid is a rare disease detected usually in 0.15% of all thyroid malignancy. We report a case of sporadic medullary microcarcinoma (MMC) of thyroid in a 24 year old male presenting as solitary thyroid nodule. There was no family history of medullary carcinoma of thyroid. Although medullary carcinoma in a familial setting have been reported, sporadic MMC is rare especially in a young patient

Inhibitory Activity of Plant Extracts on Aflatoxin B1 Biosynthesis by Aspergillus flavus

The inhibitory activities of aqueous and solvent extracts of twelve selected medicinal plants were evaluated against biosynthesis of aflatoxin B1 (AFB1) by Aspergillus flavus. The A. flavus was isolated from maize, and aflatoxin B1 biosynthesis was confirmed by comparison with standard AFB1 using TLC method. In vivo antiaflatoxigenic efficacies of activity guided solvent extracts were determined in maize model system. All the extracts showed varying degree of antifungal and AFB1 inhibitory activities, but chloroformic extract of Albizia amara, Cassia spectabilis and Solanum indicum, and methanolic extract of Acacia catechu, Albizia saman andAnogeissus latifolia showed the highest activity. Further investigations on identification of active principles from these plants are needed to develop plant based formulations for management of A. flavus growth and AFB1 contamination in food grains

Inhibitory effect of alkaloids of Albizia amara and Albizia saman on growth and fumonisin B1 production by Fusarium verticillioides

The investigation was aimed to evaluate the antifungal and antifumonisin activities of budmunchiamine A and pithecolobine against Fusarium verticillioides. The budmunchiamine A was isolated from Albizia amara and pithecolobine from Albizia saman. The results demonstrated that both budmunchiamine A and pithecolobine significantly inhibited the growth and fumonisin B1 production by F. verticillioides in a dose dependent manner. The MIC and MFC values ranged from 0.125 to 0.25 mg/ml and 0.25 to 0.5 mg/ml, respectively. In vitro evaluation showed that the fumonisin B1 production was completely inhibited by budmunchiamine A and pithecolobine at 0.25 mg/ml and 0.5 mg/ml, while in vivo evaluation showed complete inhibition at 0.25 g/kg and 0.5 g/kg, respectively. The present findings indicate the possible use of budmunchiamine A and pithecolobine as alternative agents to control the fungal and mycotoxin contaminations in food grains

Antifungal and Antimycotoxigenic Potency of Solanum torvum Swartz. Leaf Extract: Isolation and Identification of Compound Active against Mycotoxigenic Strains of Aspergillus flavus and Fusarium verticillioides

Aims The main objective of this study was to investigate the antifungal effect of Solanum torvum leaves against different field and storage fungi, and to identify its active compound. In addition, to evaluate in vitro and in vivo inhibitory efficacy on toxigenic strains of Aspergillus flavus and Fusarium verticillioides. Methods and Results Leaves of S. torvum were sequentially extracted with petroleum ether, toluene, chloroform, methanol and ethanol. The antifungal compound isolated from chloroform extract was identified as torvoside K based on spectral analysis. The antifungal activity of chloroform extract and torvoside K was determined by broth microdilution and poisoned food techniques. The minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC) and zone of inhibition (ZOI) were recorded. Further, inhibitory effects of chloroform extract and torvoside K on growth of A. flavus and F. verticillioides, and their toxin productions were evaluated using in vitro and in vivo assays. Torvoside K showed the significant activity against tested fungi with ZOIs and MICs ranging from 33·4 to 87·4% and 31·25–250 μg ml-1, respectively. Further, torvoside K showed concentration-dependent antimycotoxigenic activity against aflatoxin B1 and fumonisin B1 production by A. flavus and F. verticillioides, respectively. Conclusions It was observed that the compound torvoside K significantly inhibited the growth of all fungi tested. Growth of A. flavus and F. verticillioides, and aflatoxin B1 and fumonisin B1 productions were completely inhibited in vitro and in vivo by torvoside K with increasing concentration. Significance and Impact of the Study Control of mycotoxigenic fungi requires compounds that able to inhibit both fungal growth and mycotoxin production. The antimycotoxigenic potential of torvoside K of S. torvum is described in this study for the first time. The results indicate the possible use of S. torvum as source of antifungal agents against postharvest fungal infestation of food commodities and mycotoxin contaminations

Evaluation of Phyllanthus polyphyllus L. Extract and its Active Constituent as a Source of Antifungal, Anti-​Aflatoxigenic, and Antioxidant Activities

The present investigation was carried out to evaluate the antifungal activities of Phyllanthus polyphyllus L. leaf ext., to isolate its active constituent 4-​o-​Me gallic acid (4-​o-​MGA)​, and to det. the antioxidant and antiaflatoxigenic properties. The bioassay-​guided fractionation of methanol ext. led to the isolation of active compd. 4-​o-​methylgallic acid. The methanol ext. showed the highest amt. of phenolic content (290 mg GAE​/g dry ext.)​, which indicated the involvement of phenolic compds. in the radical scavenging activity obsd. by the methanol ext. The antioxidant capacity of 4-​o-​MGA was greater than the std. butylated hydroxytoluene, followed by methanol ext. The concn.-​dependent growth inhibitory activity was obsd. against the tested fungi, in which the field fungi were susceptible, while the storage fungi were found to be more resistant including aflatoxigenic A. flavus. A correlation was obsd. between fungal biomass and aflatoxin prodn. in control and treatment, there was a decrease in biomass of A. flavus and aflatoxin prodn. with increasing concn. The aflatoxin prodn. was completely inhibited in vitro by methanol ext. at 1 mg​/mL and 4-​o-​MGA at 2 mg​/mL, but the mycelial growth was not inhibited completely. The inhibition of aflatoxin prodn. was relatively higher than the mycelial growth inhibition of A. flavus, such behaviors might have been detd. by the presence of hydrolysable tannin 4-​o-​MGA in the ext., which is known to inhibit the aflatoxin biosynthesis. The significant antioxidant and aflatoxin inhibitory activities of P. polyphyllus could be exploited for its application in preventing oxidative deterioration and fungal spoilage of food products

Evaluation of antimicrobial and antioxidant properties of pithecolobine isolated from Albizia saman

Pithecolobine isolated from alkaloid extract of Albizia saman showed antimicrobial activity against seven human pathogenic bacteria and two yeasts with minimum inhibitory concentrations (MIC) values of 1.9-125 g mL-1. In addition, it also exhibited antioxidant activity with IC50 value at 250g mL-1. Pithecolobine may be useful as a natural bioactive molecule for developing potent antimicrobial and antioxidant agents. © 2015 Taylor and Francis Group, LLC

Antifungal and antimycotoxigenic properties of chemically characterised essential oil of Boswellia serrata Roxb. ex Colebr.

In the present investigation, the antifungal and antimycotoxigenic activities of Boswellia serrata essential oil were evaluated in vitro and in viable maize. The GC-MS analysis of B. serrata essential oil showed a total of 29 constituents, among which, 3-carene (34.74), β-ocimene (13.78), D-limonene (8.25), β-caryophyllene (6.65) and terpinolene (5.39) recorded the highest percentage. The B. serrata essential oil showed promising antifungal activity against 15 different field and storage fungi with percentage of mycelial inhibition ranged between 15.9�56.3 at 1µL mL�1. Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values were ranged between 0.039�0.625 µL mL�1 and 2.5�>10.0 µL mL�1, respectively, against the same fungi tested. The production of aflatoxin B1 and fumonisin B1 were completely inhibited by B. serrata essential oil at 6 µL mL�1in vitro. The ergosterol content was drastically decreased with the increasing concentration of B. serrata essential oil in vitro. Viable maize model confirmed that aflatoxin B1 and fumonisin B1 contents were significantly inhibited with increasing seedling vigour of maize. The results revealed that B. serrata essential oil could be explored for management of mould and mycotoxin contaminations in food grains and feedstuffs. © 2017 Taylor & Francis Group, LLC

Antifumonisin Efficacy of 2-Hydroxy-4-Methoxybenzaldehyde Isolated from Decalepis hamiltonii

Fumonisins are mycotoxins primarily produced by Fusarium verticillioides that grow on food and feedstuffs. In the present investigation, the antifumonisin activity of 2-hydroxy-4-methoxybenzaldehyde isolated from Decalepis hamiltonii was evaluated. The results demonstrated that the compound 2-hydroxy-4-methoxybenzaldehyde exhibited dose-dependent antifungal activity with the zone of inhibition, minimum inhibitory concentration and minimum fungicidal concentration values 14.8 mm (at 500 μg/disc), 100 and 500 μg/mL, respectively. The fumonisin B1 production was completely inhibited at 400 mg/L under in vitro and 750 mg/kg under in vivo. There were no adverse effects observed in treated seed samples. The present findings indicate the possible use of 2-hydroxy-4-methoxybenzaldehyde as an alternative agent for management of fusarial growth and mycotoxins contamination