3,127 research outputs found
Preparation and Characterization of a Standardized Anticonvulsant Ginseng Rb Extract from Panax quinquefolius L.
A ginseng Rb extract (GRbE) containing three major ingredients of ginsenoside Rb1 (G-Rb1), ginsenoside Rb3 (G-Rb3) and ginsenoside Rd (G-Rd) has been shown to have anticonvulsant and neuroprotective activity. As such, sufficient characterization and standardization of this active GRbE are demanded to facilitate an ongoing preclinical investigation on its potential for the treatment of epilepsy. In the investigation, the methods for generating the active GRbE and isolating G-Rb1, G-Rb3, and G-Rd in large scale from Panax quinquefolius are described. The chemical profile of GRbE was characterized by identifying the structure of the individual ingredients using NMR, and the concentration of individual ingredients was determined using HPLC. This study demonstrates the application of the established methods for reproducibly generating anticonvulsant GRbE, which is enriched in five panaxadiol glycosides of G-Rb1, ginsenoside Rb2 (G-Rb2), G-Rb3, ginsenoside Rc (G-Rc), and G-Rd with total ginsenosides over 90%, and for purifying G-Rb1, G-Gb3 and G-Rd with purity of 97.9%, 96.6% and 98.6%, respectively
An overview of genus Aesculus L.: ethnobotany, phytochemistry, and pharmacological Activities
The genus Aesculus L. (Hippocastanaceae) has 12 species distributed in eastern Asia, eastern and western North America, and Europe. In Europe and the United States, A. hippocastanum has been used for the treatment of chronic venous insufficiency, hemorrhoids, and postoperative edema. In China, A. chinensis var. chinense has been used as a stomachic and analgesic in the treatment of distention and pain in the chest and the abdomen, malaria, dysentery, and heart disease. The objective of this paper is to review the ethnobotany, phytochemistry, and pharmacological properties of the genus Aesculus. To date, more than 210 compounds have been isolated and identified primarily from the fruits or seeds of Aesculus, with polyhydroxylated triterpenoid saponins as the major active principles. Studies have confirmed that Aesculus seed extracts and isolates possess diverse activities, including anti-inflammatory, antitumor, antiviral, antifungal, antiangiogenic (vascular protection), anti-obesity, antioxidative, and antigenotoxic properties. Interestingly, detailed studies of the saponins from more eastern North American species and other uninvestigated Aesculus species are necessary to further confirm the chemotaxonomic value of the novel cytotoxic saponins discovered recently from A. pavia, an eastern North American species, and to fully understand the chemical profile of the genus. Animal investigations of these novel cytotoxic saponins on the potential for the treatment of cancer are also intriguin
Adversarial Purification of Information Masking
Adversarial attacks meticulously generate minuscule, imperceptible
perturbations to images to deceive neural networks. Counteracting these,
adversarial purification methods seek to transform adversarial input samples
into clean output images to defend against adversarial attacks. Nonetheless,
extent generative models fail to effectively eliminate adversarial
perturbations, yielding less-than-ideal purification results. We emphasize the
potential threat of residual adversarial perturbations to target models,
quantitatively establishing a relationship between perturbation scale and
attack capability. Notably, the residual perturbations on the purified image
primarily stem from the same-position patch and similar patches of the
adversarial sample. We propose a novel adversarial purification approach named
Information Mask Purification (IMPure), aims to extensively eliminate
adversarial perturbations. To obtain an adversarial sample, we first mask part
of the patches information, then reconstruct the patches to resist adversarial
perturbations from the patches. We reconstruct all patches in parallel to
obtain a cohesive image. Then, in order to protect the purified samples against
potential similar regional perturbations, we simulate this risk by randomly
mixing the purified samples with the input samples before inputting them into
the feature extraction network. Finally, we establish a combined constraint of
pixel loss and perceptual loss to augment the model's reconstruction
adaptability. Extensive experiments on the ImageNet dataset with three
classifier models demonstrate that our approach achieves state-of-the-art
results against nine adversarial attack methods. Implementation code and
pre-trained weights can be accessed at
\textcolor{blue}{https://github.com/NoWindButRain/IMPure}
Nematic crossover in BaFeAs under uniaxial stress
Raman scattering can detect spontaneous point-group symmetry breaking without
resorting to single-domain samples. Here we use this technique to study
, the parent compound of the "122" Fe-based
superconductors. We show that an applied compression along the Fe-Fe direction,
which is commonly used to produce untwinned orthorhombic samples, changes the
structural phase transition at temperature into a crossover
that spans a considerable temperature range above . Even in
crystals that are not subject to any applied force, a distribution of
substantial residual stress remains, which may explain phenomena that are
seemingly indicative of symmetry breaking above . Our results
are consistent with an onset of spontaneous nematicity only below
.Comment: 4 pages, 4 figure
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