1,009 research outputs found
Apparent solubility and dissolution profile at non-sink conditions as Quality improvement tools.
No full textNon
Evaluating behavioral avoidance and horizontal transmission of Beauveria bassiana in bed bugs (Cimex lectularius) across spatially complex environments
No full textSubmission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-08-01The student, Vinisha Basnet, accepted the attached license on 2025-07-16 at 11:38.The student, Vinisha Basnet, submitted this Thesis for approval on 2025-07-16 at 11:40.This Thesis was approved for publication on 2025-07-18 at 15:47.DSpace SAF Submission Ingestion Package generated from Vireo submission #22579 on 2025-10-21 at 10:06:07The resurgence of bed bugs (Cimex lectularius) since 1990’s has led to an increased dependence on chemical insecticides like pyrethroids and neonicotinoids for control. The use of such pesticides has further led to an evolved biological resistance among bed bug strains. As a result, the entomopathogenic fungus like Beauveria bassiana, in the form of commercial biopesticide Aprehend, is gaining attention as an alternative control measure. Laboratory studies confirm the efficacy and potential for horizontal transmission of Beauveria bassiana between bed bugs. However, we lack empirical studies that examine: (1) the extent to which bed bugs behaviorally avoid fungal spores; and (2) how spatially complex or cluttered environments affect fungal transmission in real-world situations. In this study, I conducted behavioral assays to understand if bed bugs avoid Aprehend-treated areas and if horizontal transmission decreases in spatially complex arenas and higher densities. My results showed no significant avoidance, as bed bugs chose treated and control zones at similar rates. Horizontal transmission was high across all spatially complex arenas and densities. However, survival results showed that while spatially complex arenas had no significant impact, density did affect the survival time of bed bugs exposed to Aprehend. Bed bugs in high density arenas survived longer, which could be due to some form of social protection. These findings shows that Aprehend is effective even in highly complex or cluttered environments and that density plays an important role in influencing survival time within bed bug colonies
Interpreting non-linear drug diffusion data: Utilizing Korsmeyer-Peppas model to study drug release from liposomes
No full textNanocarriers for tailored skin delivery: More than just the carriers?
No full textSkin diseases are among the top 5 most leading diseases causing non-fatal health burden worldwide and strategies to assure more effective treatments are urgently needed. Dermal therapy is very attractive due to the direct administration of the drug at the diseased skin site thus minimizing systemic side effects associated with the oral and parenteral routes. However, the great variety within the skin conditions can be a challenge in the development of effective dermal therapies. Based on the skin disease, the drug action is often required at different depths within the skin. The failure to penetrate the skin layers might result in sub-therapeutic drug levels at the targeted skin site and unsuccessful treatments. Phospholipid-based nanocarriers have great potential to overcome the current limitations in dermal therapy by assuring controlled and sustained drug delivery and promoting drug/substance transport in the deeper skin layers. The nanocarrier properties can be tailored and exploited to optimize skin drug delivery.
In the present study we optimized nanocarriers for tailored skin drug delivery. A closer-to-in vivo skin penetration model was developed to select nanocarriers with specific skin-targeted drug delivery potential. Deformable liposomes were found the most promising nanocarriers delivering model substances in the deeper skin layers while avoiding systemic absorption.
Further optimization of the selected nanocarrier was performed by exploring the effect of the liposomal surface charge on dermal delivery. The sustained skin penetration of drug/active substances for liposomally-associated drugs/substances was influenced by both the liposomal surface charge and physicochemical properties of the nanocarrier-associated drug/substance. The enhancement of the biological activities of both human epidermal growth factor and curcumin when incorporated in the liposomal system as compared to both active substances in solutions was found to be dependent on the liposomal surface charge.
Positively charged deformable liposomes embedded in chitosan hydrogel enabled stable bioadhesive hydrogel providing a sustained skin penetration of curcumin. The developed liposomal hydrogel formulation has a potential to be further evaluated as advanced wound dressing
Controlled electrochemical growth of ultra-long gold nanoribbons
No full textCitation: Basnet, G., Panta, K. R., Thapa, P. S., & Flanders, B. N. (2017). Controlled electrochemical growth of ultra-long gold nanoribbons. Applied Physics Letters, 110(7), 5. doi:10.1063/1.4976027This paper describes the electrochemical growth of branchless gold nanoribbons with similar to 40 nm x similar to 300 nm cross sections and >100 mu m lengths (giving length-to-thickness aspect ratios of > 10(3)). These structures are useful for opto-electronic studies and as nanoscale electrodes. The 0.75-1.0V voltage amplitude range is optimal for branchless ribbon growth. Reduced amplitudes induce no growth, possibly due to reversible redox chemistry of gold at reduced amplitudes, whereas elevated amplitudes, or excess electrical noise, induce significant side-branching. The inter-relatedness of voltage-amplitude, noise, and side-branching in electrochemical nanoribbon growth is demonstrated. Published by AIP Publishing
Female Employers and their Maids in New Delhi: ‘This is Our Culture’
No full textBasnet C, A.S. S. Female Employers and their Maids in New Delhi: ‘This is Our Culture’. South Asia Research. 2020;40(2):282-298.The domestic labour market in India reflects how various classes of women manage their daily lives, whether as employers of domestic workers or as employees. The cultural underpinnings of various intersecting relationships implicated in this scenario have remained underresearched in India. Based on a qualitative study in a specific neighbourhood of New Delhi, this article shows that certain cultural strategies pursued by female employers explain their differential behaviour towards specific groups of maids. Observing that these female employers in Delhi prefer Nepali maids over native Indians, even if the latter are willing to work for lower wages, we set out to analyse why and how these employers evaluate immigrant Nepali maids as sharing ‘our’ culture, while native Indians are classified as the cultural ‘other’
Microscopy Meets Nanomedicine: The Challenge of Liposomes. Selecting, Understanding, and Adapting Imaging Techniques to Localize and Characterize Nanocarriers
No full textNanocarriers have brought several medical advances through better diagnostics and improved drug therapy. Yet, many promising preclinical findings were never translated into clinical success, consequently slowing drug development, and increasing its financial burden. By reliably predicting the nanoparticle fate at in vitro stages, the disappointment of suboptimal in vivo outcome could be avoided. To tackle the challenges of in vitro settings, this project aimed at gaining deeper insight on the interaction between nanocarriers and biological environment. Specifically, advance microscopy tools were used to visualize, characterize, and follow the biological fate of nanocarriers. As a back-to-basics approach, liposomes were chosen as model nanocarriers for their versatility, biocompatibility, and clinical relevance. When including a fluorescent molecule in the liposomal formulation, fluorescence dye and nanocarrier were found to affect each other’s properties in a manner dependent on environmental conditions (e.g., temperature, time, medium, and dye-specific chemistry). The fluctuations of fluorescence in the sample were further analyzed through image processing algorithms to obtain super resolution information from a diffraction-limited multi-frame acquisition. In parallel, to overcome some of the disadvantages often linked to the use of fluorescence, quantitative phase microscopy was optimized as a complementary label-free technique for the localization and characterization of liposomes in their hydrate state. Finally, fluorescence and label-free imaging were combined to determine the integrity of liposomes in nanofibers for topical administration. To understand the behavior of liposomes in cell culture, their internalization was followed using high throughput screenings, based on flow cytometry. These batch-mode results were validated in flow imaging and confocal microscopy. The behavior of liposomes, with and without PEG-coating, was compared in terms of intracellular localization and overall cellular response, resorting to the combination of fluorescence and label-free imaging (here, confocal and electron microscopy). Volumetric image correlation was then attempted, discussing benefits and limitations of the methods involved.Nanobærere har brakt med seg flere medisinske fordeler gjennom bedre diagnostikk og legemiddelterapi. Likevel er det mange prekliniske funn som aldri har blitt omsatt til klinisk suksess. Dette har resultert i langsommere legemiddelutvikling og økt finansiell byrde. Gjennom pålitelig bestemmelse av nanopartiklers skjebne under in vitro stadier kan man unngå skuffelsen av suboptimale in vivo resultater. For å håndtere utfordringene innenfor in vitro betingelser, sikter dette prosjektet på å oppnå dypere forståelse av interaksjonene mellom nanobærere og de biologiske omgivelsene. Her ble avanserte mikroskopiske verktøy brukt til å visualisere, karakterisere og følge den biologiske skjebnen til nanobærerne. Gjennom en tilnærming basert på grunnleggende prinsipper, ble liposomer valgt som modell for nanobærerne på grunn av deres allsidighet, biokompatibilitet og kliniske relevans. Når man inkluderte et fluorescerende molekyl i den liposomale formuleringen fant man ut at det fluorescerende fargestoffet og nanobæreren påvirket hverandres egenskaper på en måte som er avhengig av miljøforhold (f.eks. temperatur, tid, medium og kjemi spesifikt for fargestoffet). Fluktueringen av fluorescens i prøven ble videre analysert gjennom algoritmer for bildeprosessering for å oppnå informasjon om superoppløsning fra en diffraksjonsbegrenset datafangst gjennom flere billedtakninger. Parallelt, for å omgå noen av ulempene som ofte er knyttet opp mot bruk av fluorescens, ble kvantitativ fasemikroskopi optimalisert som en komplementær merkingsfri teknikk for lokalisering og karakterisering av liposomer i hydrert tilstand. Til slutt ble fluorescerende og merkingsfri billedtakning kombinert for å se på integriteten til liposomer i nanofibre laget for topikal administrasjon. For å forstå oppførselen til liposomer i cellekulturer ble deres internalisering fulgt gjennom screening av høyt volum, basert på flowcytometri. Disse resultatene ble validert gjennom flow imaging og konfokalmikroskopi. Oppførselen til liposomer, med og uten PEG-overtrekk, ble sammenlignet med hensyn til intracellulær lokalisering og total cellulær respons, gjennom en kombinasjon av fluorescens og merkingsfri billedtakning (konfokal og elektronmikroskopi). Volumetrisk bildekorrelasjon ble deretter utforsket gjennom drøfting av fordeler og begrensninger ved de involverte metodene
The role of erythromycin C-12 hydroxylase, EryK, as a substitute for PikC hydroxylase in pikromycin biosynthesis
No full textThe substrate flexibility of the erythromycin C-12 hydroxylase from Saccharopolyspora erythraea, EryK, was investigated to test its potential for the generation of novel polyketide structures. We have shown that EryK can accept the substrates of PikC from Streptomyces venezuelae which is responsible for the hydroxylation of YC-17 and narbomycin. In a S. venezuelae pikC deletion mutant, EryK could catalyze the hydroxylation of YC-17 and narbomycin to generate methymycin/neomethymycin and pikromycin, respectively. Molecular modeling of the enzyme-substrate complex suggested the possible interaction of EryK with alternative substrates. The results indicate that EryK is flexible toward some alternative polyketides and can be useful for structural diversification of macrolides by post-polyketide synthase hydroxylation.open
Satis Devkota
No full textBasnet, H. C.; Devkota, S.; and Upadhyay, M. (2021). Terms of trade and real domestic income: New evidence from South and Southeast Asia. International Journal of Finance & Economics, Vol. 26, No. 3, pp. 4315-4331.https://digitalcommons.morris.umn.edu/cosa2022/1014/thumbnail.jp
Managing risks in maritime remote pilotage using the basis of the Formal Safety Assessment
No full textMaritime pilotage is conducted in congested areas, where the risk of collision and grounding accidents is high. Hence, the pilotage operation is safety critical and has been established as a mandatory service in many countries. However, with Remote Pilotage (RP) and related technological transformation, there is a need to adapt risk management methods to address emerging risks. This thesis aims to develop a framework to manage risks in RP by identifying gaps in the Formal Safety Assessment (FSA) framework and proposes novel solutions to fulfill them.
The thesis investigates Model-Based Systems Engineering (MBSE) for creating unambiguous system description models for the risk management process. Furthermore, this thesis addresses the selection challenge in MBSE by proposing a framework that assists system developers in choosing suitable MBSE language. Building upon the model, the thesis combines, System-Theoretic Process Analysis (STPA) and Bayesian Network (BN) for hazard identification and risk analysis. To reduce the limitations of other STPA-BN studies, the thesis explores the application of complexity reduction techniques such as the Parent Divorcing Technique, Noisy-OR gates, and the sub-models. Moreover, the thesis extends the STPA-BN method with a cost-benefit analysis using Influence Diagrams (IDs) for selecting a cost-effective Risk Control Option (RCO). Lastly, the thesis provides a methodology for the automatic generation of a BN risk model using an incident database and programming language, which facilitates real-time risk monitoring.
The proposed frameworks and solutions are then applied to RP for managing risks in early design phases. System description models, developed with selected MBSE language, are used together with STPA to identify the RP risk events such as losses, accidents, hazards, and causal factors. For each of these risk events, the occurrence probability is determined using a BN model. The model shows that the losses with high occurrence probability are loss of customer satisfaction, damage to the ship, injury to people, and damage to the environment. Furthermore, the model shows that collision and contact accidents have a higher occurrence probability than grounding during RP in Finnish fairways. For controlling these risk events in RP, an ID is developed and numerous RCOs are evaluated based on cost-benefit analysis. As a result, a cost-effective RCO for RP is proposed in the thesis. Finally, an automatic generation of BN risk models using a pilotage incident database and Python is demonstrated. The developed tool generates and updates the BN model providing the occurrence probability of risk events for real-time risk monitoring.
The results of this thesis demonstrate the applicability and effectiveness of the proposed framework. Furthermore, this thesis provides an essential foundation for managing risks in RP and facilitates its development. Last but not least, the thesis provides tools and methods supporting stakeholders in making risk-based decisions involving advanced systems
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