Organic liquid scintillation detectors are widely used to measure the presence of radiation. With these devices, there are advantages in that they are easy to manufacture, large in size, and have a short fluorescence decay time. However, they are not suitable for gamma spectroscopy because they are composed of a low-atomic-number material.
View Article and Find Full Text PDFThe abnormal self-assembly of amyloid-beta (Aβ) peptides into oligomers, as well as insoluble fibrils, has been identified as a key factor for monitoring the progression of Alzheimer's disease (AD). The noninvasive imaging of Aβ aggregates utilizing chemical probes can be a powerful and practical technique for accurately diagnosing and monitoring the progress of AD, as well as evaluating the effectiveness of therapeutic drug candidates in treating or managing it. Particularly, the near-infrared (NIR) fluorescence imaging of Aβ plaques is a potentially promising approach toward the efficient detection of the biomarker.
View Article and Find Full Text PDFDual-modular imaging approaches combining near-infrared (NIR) fluorescence (FLI) and photoacoustic imaging (PAI) require suitable contrast agents to produce dual-modular signals. Although nanoparticles have been used to develop PAI agents, small molecule-based imaging agents have not been extensively studied, highlighting the need to design new fluorophores with an enhanced multifunctional ability. Thus, in this study, we designed a novel squaraine (SQ)-based dye and reported its rational preparation and conjugation with a cancer targeting peptide.
View Article and Find Full Text PDFPeroxynitrite (ONOO), a highly reactive oxygen species generated by the reaction of nitric oxide and superoxide radical anion, is involved in numerous physiological and pathological processes in the human body. To identify important pathogenic mechanisms, it is crucial to develop a reliable tool for detecting peroxynitrite in living systems. In the present study, a new difluoroboron β-diketonate-based fluorescent probe for detecting exogenous and endogenous peroxynitrite in living systems was designed.
View Article and Find Full Text PDFJ Anal Methods Chem
February 2018
Accumulation of -amyloid (A) plaques comprising A40 and A42 in the brain is the most significant factor in the pathogenesis of Alzheimer's disease (AD). Thus, the detection of A plaques has increasingly attracted interest in the context of AD diagnosis. In the present study, a fluorescent pyridazine-based dye that can detect and image A plaques was designed and synthesized, and its optical properties in the presence of A aggregates were evaluated.
View Article and Find Full Text PDFA boronic acid-based fluorescent probe was developed for diagnosis of amyloid-β (Aβ) plaques from Alzheimer's disease (AD). Probe 4c, which included boronic acid as a functional group, exhibited a significant increase (64.37-fold, FAβ/F0) in fluorescence intensity as a response to Aβ aggregates, with a blue shift (105nm) in the maximum emission wavelength.
View Article and Find Full Text PDFβ-amyloid (Aβ) plaques in the brain are composed of Aβ40 and Aβ42 peptides, and are the defining pathological feature of Alzheimer's disease (AD). Fluorescent probes that can detect Aβ plaques have gained increasing interest as potential tools for in vitro and in vivo monitoring of the progression of AD. In this study, chalcone-mimic fluorescent probe 5 was designed and prepared.
View Article and Find Full Text PDFAmyloid plaques, which are primarily composed of aggregated amyloid-beta (Aβ) peptide, are the neuropathological hallmarks of Alzheimer's disease (AD). Fluorescent markers containing 2-styrylpyridazin-3(2H)-ones were developed to detect intracellular aggregated Aβ peptides. Nine compounds exhibited a greater than 10-fold increase of in emission spectra before and after mixing with Aβ aggregates compared with before mixing.
View Article and Find Full Text PDFA series of 1,3-diarylprop-2-en-1-one derivatives 3a-v have been synthesized and evaluated for their ability to inhibit neuraminidase (NA). Among the prepared compounds, the less lipophilic derivative 3k showed the most potent in vitro inhibitory activity against NA with an IC(50) value of 1.5 μM.
View Article and Find Full Text PDFThe anti-inflammatory activities of a prepared isoegomaketone 3a and its derivatives 3b-3f were evaluated in RAW 264.7 cells. Among these, the compound 3d was displayed the most potent inhibitory activities against production of nitric oxide, monocyte chemoattractant protein-1 and interleukin-6.
View Article and Find Full Text PDFIsoegomaketone (IK) is an essential oil component of Perilla frutescens (L.), but the mechanism by which IK induces apoptosis has never been studied. The purpose of this study was to elucidate the IK-induced apoptotic pathway in DLD1 human colon cancer cells.
View Article and Find Full Text PDFIsoegomaketone (IK) is an essential oil component of Perilla frutescens (L.) Britt., and there have been no studies investigating its biological activities.
View Article and Find Full Text PDFHigh quality, single-crystal silicon nanowires were successfully grown from silicon wafers with a nickel catalyst by utilizing a solid-liquid-solid (SLS) mechanism. The nanowires were composed of a crystalline silicon core with an average diameter of 10 nm and a thick outer oxide layer of between 20 and 30 nm at a growth temperature of 1000 °C. When utilizing the SLS growth mechanism, the diameter of the silicon nanowire is dependent solely upon the growth temperature, and has no relation to either the size or the shape of the catalyst.
View Article and Find Full Text PDFAcyl-CoA: cholesterol acyltransferase (ACAT) plays an important role in the esterification of cholesterol with its substrates, cholesterol and fatty acyl coenzyme A, to facilitate both intracellular storage and intercellular transport. ACAT-1 is more involved in macrophage foam cell formation and ACAT-2 plays a critical role in the cholesterol absorption process in intestinal enterocytes. Three aliphatic acid amides, beta-sanshool (1), gamma-sanshool (2), and hydroxy-beta-sanshool (3), were isolated by bioassay-guided fractionation of the ethanolic extracts of Zanthoxylum piperitum DC.
View Article and Find Full Text PDFBioorg Med Chem Lett
February 2007
Three naphthoquinones were isolated by bioassay-guided fractionation from the CHCl(3) extracts of roots of Lithospermum erythrorhizon. They were identified as acetylshikonin (1), isobutyrylshikonin (2), and beta-hydroxyisovalerylshikonin (3) on the basis of their spectroscopic analyses. The compounds 1-3 were tested for their inhibitory activities against human ACAT-1 (hACAT-1) or human ACAT-2 (hACAT-2).
View Article and Find Full Text PDFThe catecholic xanthones and flavonoids 1-13 were isolated from the root bark of Cudrania tricuspidata. Compounds 1 and 3-8 exhibited significant antioxidant activity against low-density lipoprotein (LDL) oxidation in the thiobarbituric acid-reactive substance (TBARS) assay. Among them, prenylated flavonoids 10-12 showed an inhibitory effect on the NO production and iNOS expression in RAW264.
View Article and Find Full Text PDFA series of multi-substituted oximes were prepared and their potencies for inhibiting lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) activity were evaluated in vitro. Among them, compounds 3a, 3b, and 3m were identified to display a micromolar potency for inhibiting Lp-PLA(2) in whole human plasma and isolated human LDL. Based on these results, structure-activity relationship was studied on modification of three parts of R(1), R(2), and R(3) to identify a potent pharmacophore for Lp-PLA(2).
View Article and Find Full Text PDFAcyl-CoA: cholesterol acyltransferase (ACAT) catalyzes the acylation of cholesterol to cholesteryl ester with long chain fatty acids and ACAT inhibition is a useful strategy for treating hypercholesterolemia or atherosclerosis. Pentacyclic triterpenes, ursolic acid (1), oleanolic acid (2), and betulinic acid (3) were isolated from the methanol extracts of the leaves of Lycopus lucidus TURCZ. by bioassay-guided fractionation.
View Article and Find Full Text PDF(R)-Glycerol-monolinoleate 4 and (R)-glycerol-monostearate 5 were isolated from the ethyl acetate extracts of Saururus chinensis roots and (R)- or (S)-fatty acid glycerols 4 and 5 were synthesized for confirming their structures and evaluating their inhibitory activities against Lp-PLA(2). The (R)-4 and (S)-4 exhibited Lp-PLA(2) inhibitory activities with IC(50) values of 45.0 and 52.
View Article and Find Full Text PDFPyrido[2,3-b][1,4]oxazin-2-ones are conveniently prepared in excellent yields by a one-pot annulation of N-substituted-2-chloroacetamides with 2-halo-3-hydroxypyridines with use of cesium carbonate in refluxing acetonitrile. The key transformation features a Smiles rearrangement of the initial O-alkylation product and subsequent cyclization.
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