We report the first microsampling device for reliably quantitative, label-free and separation-free detection of multicomponents of surface organic residues (SORs) by means of a quality controllable surface-enhanced Raman scattering (SERS)-enabled micropipette. The micropipette is comprised of a drawn glass capillary with a tiny orifice (∼50 μm) at the distal tip, where the specially designed nanorattles (NRs) are compactly coated on the inner wall surface. SERS signals of 4-mercapto benzoic acid (MBA) anchored inside the internal gap of NRs could be used to evaluate and control the quality of micropipettes and, therefore, allow us to overcome the limitations of a reliably quantitative SERS assay using traditional substrates without an internal standard. By dropping a trace extraction agent on targeting SORs located on a narrow surface, the capillary and SERS functionalities of these micropipettes allow on-site microsampling via capillary action and subsequent multiplex distinction/detection due to their molecularly narrow Raman peaks. For example, 8 nM thiram (TMTD), 8 nM malachite green (MG), and 1.5 μM (400 ppb) methyl parathion (MPT) on pepper and cucumber peels have been simultaneously detected in a wide detection range. The portable SERS-enabled device could potentially be facilely incorporated with liquid-liquid or solid phase micro-extracting devices for a broader range of applications in rapid and field analysis of food/public/environment security related SORs.
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http://dx.doi.org/10.1021/acs.analchem.5b01635 | DOI Listing |
Amino Acids
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Department of Nutrition, School of Public Health, Iran University of Medical Sciences, Tehran, Iran.
Recent studies have suggested that the interaction between diet and an individual's genetic predisposition can determine the likelihood of obesity and various metabolic disorders. The current study aimed to examine the association of dietary branched-chain amino acids(BCAAs) and aromatic amino acids(AAAs) with the expression of the leptin and FTO genes in the visceral and subcutaneous adipose tissues of individuals undergoing surgery. This cross-sectional study was conducted on 136 Iranian adults, both men and women, aged ≥18 years.
View Article and Find Full Text PDFAnal Chem
January 2025
The Jiangxi Province Key Laboratory for Diagnosis, Treatment, and Rehabilitation of cancer in Chinese Medicine, Jiangxi University of Chinese Medicine, Nanchang 330004, P. R. China.
An online reactive internal extraction electrospray ionization (iEESI) method was developed for the rapid determination of organic and inorganic speciation information for selenium in poultry tissue samples without complex sample pretreatment. The addition of citric acid as a reducing agent to the internal extraction solvent of methanol/acetic acid (99:1, V/V) for iEESI resulted in the reduction of selenate in the sample to selenite, accompanied by the production of malic acid as an oxidation product. The quantitative analysis of selenate was conducted by using malic acid.
View Article and Find Full Text PDFBiochem Mol Biol Educ
January 2025
Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio, USA.
We created a novel laboratory experience where undergraduate students explore the techniques used to study protein misfolding, unfolding, and aggregation. Despite the importance of protein misfolding and aggregation diseases, protein unfolding is not typically explored in undergraduate biochemistry laboratory classes. Yeast alcohol dehydrogenase (YADH) is used in the undergraduate biochemistry laboratory course at Miami University as the model system to explore protein overexpression and purification, bioinformatics, and enzyme characterization.
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December 2024
Department of Industrial Engineering and Management, Shanghai Jiao Tong University, Shanghai 200240, China.
Taking the titanium alloy wing-body connection joint at the rear beam of a certain type of aircraft as the research object, this study analyzed the failure mechanism and verified the structural safety of the wing-body connection joint under actual flight loads. Firstly, this study verified the validity of the loading system and the measuring system in the test system through the pre-test, and the repeatability of the test was analyzed for error to ensure the accuracy of the experimental data. Then, the test piece was subjected to 400,000 random load tests of flight takeoffs and landings, 100,000 Class A load tests, and ground-air-ground load tests, and the test piece fractured under the ground-air-ground load tests.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Agricultural Information Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Deep learning-based morphometric analysis of zebrafish is widely utilized for non-destructively identifying abnormalities and diagnosing diseases. However, obtaining discriminative and continuous organ category decision boundaries poses a significant challenge by directly observing zebrafish larvae from the outside. To address this issue, this study simplifies the organ areas to polygons and focuses solely on the endpoint positioning.
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