111 research outputs found
Spatiotemporally-controlled droplet merging reveals 2D diffusion dynamics of multi-component surfactants
No full textInvestigating the two-dimensional (2D) diffusion dynamics of multi-component surfactant systems is challenging due to the difficulty in establishing well-defined initial boundaries both temporally and spatially. To overcome this challenge, we employed two key strategies. First, we utilized a merging droplet technique which provides controlled spatiotemporal initial conditions, enabling in-situ measurement of multi-component surfactant diffusion. Second, we designed a model multi-component surfactant system comprising oxidized dioleoylphosphatidylcholine (oxDOPC) and cholesterol (Chol) through controlled UV-induced oxidation of DOPC. By using 1H nuclear magnetic resonance (NMR) spectroscopy and numerical simulations of diffusion with a moving boundary, we quantified the molecular profiles and diffusivities of miscible and immiscible species in oxDOPC-Chol system. Furthermore, we determined the line tension of oxDOPC domain from the elastic relaxation of its deformed shape. This work provides significant methodological advancements for studying molecular mixing in multi-component interfacial materials, including systems involving membrane proteins and lipid rafts.
Highly wrinkled reduced graphene oxide nanocomposite coating for a multiplexed electrochemical biosensor
No full textNanomaterial-based electronic devices, with dimensions akin to biological molecules and unique chemical attributes, play a pivotal role in various biomedical applications. However, achieving cost-effective and large-scale fabrication of nanomaterial-based thin films while precisely controlling nanostructures poses considerable challenges, hindering their widespread industrial adoption. To address this, we introduce meniscus-guided coating for the fabrication of reduced graphene oxide nanocomposite with high surface area and excellent electroconductive properties in a facile and scalable manner. Using computational fluid dynamics modeling, we systematically analyzed the rheological properties of the solution containing reduced graphene oxide and chitosan, optimizing coating speed conducive to the stable formation of an elongated meniscus. Additionally, we employed in situ high-speed microscopy to observe the solidification kinetics, enabling an understanding of the wrinkle formation mechanism that enhances the overall surface area. Compared to thicker coatings (similar to hundreds of nanometers), the optimized nanocomposite exhibited a 62% increase in surface area and a 97% enhancement in electroconductivity. Consequently, a multiplexed biosensor featuring this highly wrinkled thin nanocomposite simultaneously detected three antibodies related to endoplasmic reticulum stress on the same chip without any cross-reactivity: anti-PDIA6, anti-PERK, and anti-GRP78, with limit of detection of 65.94 pg mL(-1), 102.58 pg mL(-1), 53.90 pg mL(-1), respectively. This nanomaterial coating technology holds promise in overcoming barriers that hinder precise control of nanostructures within thin films, facilitating the transition to mass-production of the multiplexed sensors in biomedical fields, such as point-of-care diagnostics and healthcare monitoring.
Micrometer-thick and porous nanocomposite coating for electrochemical sensors with exceptional antifouling and electroconducting properties
No full textAbstract Development of coating technologies for electrochemical sensors that consistently exhibit antifouling activities in diverse and complex biological environments over extended time is vital for effective medical devices and diagnostics. Here, we describe a micrometer-thick, porous nanocomposite coating with both antifouling and electroconducting properties that enhances the sensitivity of electrochemical sensors. Nozzle printing of oil-in-water emulsion is used to create a 1 micrometer thick coating composed of cross-linked albumin with interconnected pores and gold nanowires. The layer resists biofouling and maintains rapid electron transfer kinetics for over one month when exposed directly to complex biological fluids, including serum and nasopharyngeal secretions. Compared to a thinner (nanometer thick) antifouling coating made with drop casting or a spin coating of the same thickness, the thick porous nanocomposite sensor exhibits sensitivities that are enhanced by 3.75- to 17-fold when three different target biomolecules are tested. As a result, emulsion-coated, multiplexed electrochemical sensors can carry out simultaneous detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid, antigen, and host antibody in clinical specimens with high sensitivity and specificity. This thick porous emulsion coating technology holds promise in addressing hurdles currently restricting the application of electrochemical sensors for point-of-care diagnostics, implantable devices, and other healthcare monitoring systems
Investigation of Genetic Factors Controlling Capsiate Biosynthesis in Pepper
Get PDF학위논문 (석사)-- 서울대학교 대학원 : 식물생산과학부(원예과학전공), 2014. 2. 강병철.Capsinoid which were found recently in non-pungent pepper show the same biological effects as capsaicinoid including anticancer and anti-obesity. A precursor of capsinoid, vanillyl alcohol, is known to be produced by mutations in the putative-aminotransferase (pAMT) gene. In the previous study, it was reported that capsinoid production is also controlled by the capsaicin synthase (CS) gene. However the relation between the CS activity and capsinoid contents has not been fully understood. This study was conducted to elucidate the role of CS in quantitative control of capsinoid contents. In the previous study, C. chinense, SNU11-001, which contains capsinoid higher than C. annuum CH-19 Sweet was identified. Non-functional mRNA of SNU11-001 had stop codon resulted from 403bp insertion and 45bp deletion. I analyzed the CS and pAMT activity using the five Capsicum accessions containing different levels of pungency including SNU11-001, the transcription levels of CS were higher in pungent Capsicum accessions. Molecular markers which can distinguish CS and pAMT genotype between SNU11-001 and pungent pepper cultivar Habanero were developed. To investigate SNU11-001 x Habanero F2 population was constructed and analyzed correlation between capsaicinoid and capsinoid concentration and CS genotypes of SNU11-001 and Habanero. Therefore, CS genotype of SNU11-001 and Habanero did not have influence on quantitative trait of capsinoid. Genetic factor which is not related in capsaicinoid biosynthesis might exist quantitative control of capsinoid synthesis. Transcriptome analysis between Capsicum pepper with capsinoid and pungent cultivar will identify effect on regulation of capsinoid contents in future studies.ABSTRACT………………………………………………………………..i
CONTENTS………………………………………………………………iii
LIST OF TABLES…………………………………………………………v
LIST OF FIGURES……………………………………………………….vi
INTRODUCTION…………………………………………………………1
LITERATURE REVIEW……………………………………………………4
MATERIALS AND METHODS
Plant materials ……………………………………………………… 11
pAMT and CS genotype analysis……………………………………. 11
DNA extraction…………………………….……..….……………. 12
Isolation RNA and cDNA synthesis……………………………….. 13
HPLC analysis of capsaicinoid and capsinoid……………………… 13
RESULTS
Capsaicinoid and capsinoid contents of the five cultivars…………… 15
Construction of populations segregating capsinoid contents………… 18
Analysis of pAMT and CS expression patterns in five cultivars………18
cDNA sequence analysis of pAMT and CS alleles…………………… 21
Marker development for pAMT and CS……………………………… 24
Segregation of pAMT and CS alleles in an F2 population…………… 27
Capsinoid and capsaicinoid contents in an F2 population…………… 30
DISCUSSION…………………………………………………………… 35
REFERENCES……...…………………………………………………… 38
ABSTRACT IN KOREAN…………………………………………… 41Maste
[4-(2-tert-Butoxy-2-oxoethoxy)naphthalen-1-yl]diphenylsulfonium trifluoromethanesulfonate
No full textIn the cation of the title salt, C28H27O3S+·CF3O3S−, the dihedral angle between the naphthalene ring system and the –C(=O)—O– plane is 80.39 (9)°. The three methyl groups of the tert-butyl group are each disordered over two orientations with an occupancy ratio of 0.712 (18):0.288 (18)
Feasibility of image-guided radiotherapy based on tomotherapy for the treatment of locally advanced anal carcinoma
No full textThe standard of care for locally advanced anal cancer has been concurrent chemoradiation. However, conventional treatment with 3-dimensional radiotherapy is associated with significant toxicity. The feasibility of new radiotherapy techniques such as image-guided radiotherapy (IGRT) in combination with chemotherapy for the treatment of this malignancy was assessed
Thermal Characterization of AI Applications on AI Accelerators-equipped Microcontrollers
No full textWe investigate the thermal characteristics of tiny ML devices with AI accelerators, to understand the thermal impact on wearable devices. We identify the unique characteristics of temperature measurement, temporal and spatial temperature variation, define two novel temperature metrics, saturation temperature and rate, and report these metrics for each compute component. For the analysis, we conduct various benchmarks and evaluate the thermal profiles of different AI applications and tasks. The results and insights lay an empirical foundation for the development of heat-safe wearable hardware
A Comparison of the Pharmacokinetics and Safety of Dapagliflozin Formate, an Ester Prodrug of Dapagliflozin, to Dapagliflozin Propanediol Monohydrate in Healthy Subjects
No full textHyun Chul Kim,1,2 Sangmi Lee,1,2 Siyoung Sung,3 Eunjin Kim,3 In-Jin Jang,1 Jae-Yong Chung4 1Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul, Republic of Korea; 2Integrated Major in Innovative Medical Science, Seoul National University Graduate School, Seoul, Republic of Korea; 3Dong-A ST Research Institute, Yongin-si, Gyeonggi-do, Republic of Korea; 4Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Bundang Hospital, Seongnam-si, Gyeonggi-do, Republic of KoreaCorrespondence: Jae-Yong Chung, Seoul National University College of Medicine and Bundang Hospital, Seongnam-si, Gyeonggi-do, 13620, Republic of Korea, Tel +82-31-787-3955, Fax +82-31-787-4045, Email [email protected]: Dapagliflozin formate (DAP-FOR, DA-2811), an ester prodrug of dapagliflozin, was developed to improve the stability and pharmaceutical manufacturing process of dapagliflozin, a sodium-glucose cotransporter-2 inhibitor.Purpose: This study aimed to evaluate the pharmacokinetics (PKs) and safety of dapagliflozin for DAP-FOR compared to those for dapagliflozin propanediol monohydrate (DAP-PDH, Forxiga) in healthy subjects.Methods: This was an open-label, randomized, single-dose, two-period, two-sequence crossover study. The subjects received a single dose of DAP-FOR or DAP-PDH 10 mg in each period, with a 7-day washout. Serial blood samples for PK analysis were collected up to 48 hours after a single administration to determine plasma concentrations of DAP-FOR and dapagliflozin. PK parameters were calculated using a non-compartmental method and compared between the two drugs.Results: In total, 28 subjects completed the study. DAP-FOR plasma concentrations were not detected in all of the blood sampling time points except for one time point in one subject, and the corresponding DAP-FOR plasma concentration in the subject was close to the lower limit of quantification. The mean plasma concentration–time profiles of dapagliflozin were comparable between the two drugs. The geometric mean ratios and its 90% confidence intervals of the maximum plasma concentration and area under the plasma concentration–time curve of dapagliflozin for DAP-FOR to DAP-PDH were within the conventional bioequivalence range of 0.80– 1.25. Both drugs were well-tolerated, with a similar incidence of adverse drug reactions.Conclusion: The rapid conversion of DAP-FOR into dapagliflozin led to the extremely low exposure of DAP-FOR and comparable PK profiles of dapagliflozin between DAP-FOR and DAP-PDH. The safety profiles were also similar between the two drugs. These results suggest that DAP-FOR can be used as an alternative to DAP-PDH.Keywords: prodrugs, dapagliflozin, pharmacokinetics, clinical trial, phase
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