Theranostics, which is the combination of both therapeutic and diagnostic capacities in one dose, is a promising tool for both clinical application and research. Although there are many chromophores available for optical imaging, their applications are limited due to the photobleaching property or intrinsic toxicity. Curcumin, a natural compound extracted from the rhizome of curcuma longa, is well known thanks to its bio-pharmaceutical activities and strong fluorescence as biocompatible probe for bio-imaging. In this study, we aimed to fabricate a system with dual functions: diagnostic and therapeutic, based on poly(lactide)-tocopheryl polyethylene glycol succinate (PLA-TPGS) micelles co-loaded curcumin (Cur) and paclitaxel (PTX). Two kinds of curcumin nanoparticle (NP) were fabricated and characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy and dynamic light scattering methods. The cellular uptake and fluorescent activities of curcumin in these systems were also tested by bioassay studies, and were compared with paclitaxe-oregon. The results showed that (Cur + PTX)-PLA-TPGS NPs is a potential system for cancer theranostics.
The study examines direct and indirect impacts of organizational commitment on employee motivation through two mediating factorsopportunistic behavior and knowledge sharing-in Vietnamese enterprises. The samples were selected by the non-probability sampling method followed convenient sampling, relatively stratified by localities in Vietnam. The sample size was 636 employees in Vietnamese enterprises. The number of collected online questionnaires was 379, while the number of valid questionnaires was 329. In the direct survey, the number of distributed questionnaires was 750, while the number of collected questionnaires was 421 and the number of valid questionnaires was 307. The total number of valid questionnaires used for analysis was 636. The study used quantitative methods with structural equation modeling analysis. The results indicate that among the components of organizational commitment, normative commitment has both direct and indirect impacts on employee motivation through two mediating factors: opportunistic behavior and knowledge sharing. Meanwhile, affective commitment has only an indirect impact on employee motivation through these mediating factors. Continuance commitment has both direct and indirect impacts; however, it has only an indirect impact on employee motivation through opportunistic behavior. In addition, the results show opportunistic behavior has a negative impact on the knowledge sharing of employees in enterprises.
Three new C29 sterols with a cyclopropane ring cyclized between C-26 and C-27 of the side chain, aragusterol I (1), 21-O-octadecanoyl-xestokerol A (4), and 7β-hydroxypetrosterol (5b), were isolated from the Vietnamese marine sponge Xestospongia testudinaria, along with the known compounds, aragusterol B (2), xestokerol A (3), 7α-hydroxypetrosterol (5a), 7-oxopetrosterol (6), and petrosterol (7). The structures of the new compounds were established by analysis of spectroscopic data including 1D and 2D NMR, and high-resolution electrospray ionization mass spectrometry (HRESIMS). Their capacity to inhibit the adhesion of isolated bacteria from marine biofilms was evaluated against the bacterial strains Pseudoalteromonas sp. D41, Pseudoalteromonas sp. TC8, and Polaribacter sp. TC5. Aragusterol B (2) and 21-O-octadecanoyl-xestokerol A (4) exhibited the most potent antifouling activity with EC50 values close to these reported in the literature for tributyltin oxide, a marine anti-biofouling agent now considered to be a severe marine pollutant. Due to its comparable activity to tributyltin oxide and its absence of toxicity, the new 26,27-cyclosterol, 21-O-octadecanoyl-xestokerol A (4) constitutes a promising scaffold for further investigations.
We show that negative differential conductance (NDC) can be observed in metallic quantum dot structures. For a simple model at zero temperature we have derived an analytical expression for the current–voltage characteristics and a condition for observing NDC. For devices with gates at finite temperatures, using the Monte Carlo method we have suggested diagrams describing a correlation between the gate capacitance or temperature and the inter-dot coupling in producing (or removing) NDC.
Context: A methanol extract of Cyperus rotundus L. (Cyperaceae) rhizomes showed inhibitory activity against a-glucosidase and a-amylase, two enzymes involve in carbohydrate digestion. Objective: Identification of compounds from C. rotundus rhizomes responsible for the inhibition of a-glucosidase and a-amylase. Materials and methods: Compounds were identified by a phytochemical investigation using combined chromatographic and spectroscopic methods. a-glucosidase and a-amylase inhibitory activities were evaluated by in vitro enzyme inhibition assays.0 ,5,6,7,8-hexahydroxyflavane (1), together with three known stilbene dimers cassigarol E (2), scirpusin A (3) and B (4) were isolated. Compound 2 inhibited both a-glucosidase and a-amylase activities while the flavane 1 only showed effect on a-amylase, and compounds 3 and 4 were active on a-glucosidase. All four compounds showed significant 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. Discussion: The inhibitory activities against a-amylase and a-glucosidase of the C. rotundus rhizomes were reported for the first time. Stilbene dimers are considered as potent inhibitors of a-glucosidase and promising antihyperglycemic agents. Conclusion: The isolated compounds may contribute to the antidiabetic property of C. rotundus.
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