Electrochemical reduction of halogenated organic compounds is gaining increasing attention as a strategy for the remediation of environmental pollutants. We begin this review by discussing key ...components (cells, electrodes, solvents, and electrolytes) in the design of a procedure for degrading a targeted pollutant, and we describe and contrast some experimental techniques used to explore and characterize the electrochemical behavior of that pollutant. Then, we describe how to probe various mechanistic features of the pertinent electrochemistry (including stepwise versus concerted carbon-halogen bond cleavage, identification of reaction intermediates, and elucidation of mechanisms). Knowing this information is vital to the successful development of a remediation procedure. Next, we outline techniques, instrumentation, and cell designs involved in scaling up a benchtop experiment to an industrial-scale system. Finally, the last and major part of this review is directed toward surveying electrochemical studies of various categories of halogenated pollutants (chlorofluorocarbons; disinfection byproducts; pesticides, fungicides, and bactericides; and flame retardants) and looking forward to future developments.
Resveratrol as an anti-cancer agent: A review Rauf, Abdur; Imran, Muhammad; Butt, Masood Sadiq ...
Critical reviews in food science and nutrition,
06/2018, Letnik:
58, Številka:
9
Journal Article
Recenzirano
Owing to their antimicrobial, antioxidant, and anti-inflammatory activity, grapes (Vitis vinifera L.) are the archetypal paradigms of fruits used not only for nutritional purposes, but also for ...exclusive therapeutics. Grapes are a prominent and promising source of phytochemicals, especially resveratrol, a phytoalexin antioxidant found in red grapes which has both chemopreventive and therapeutic effects against various ailments. Resveratrol's role in reducing different human cancers, including breast, cervical, uterine, blood, kidney, liver, eye, bladder, thyroid, esophageal, prostate, brain, lung, skin, gastric, colon, head and neck, bone, ovarian, and cervical, has been reviewed. This review covers the literature that deals with the anti-cancer mechanism of resveratrol with special reference to antioxidant potential. Furthermore, this article summarizes the literature pertaining to resveratrol as an anti-cancer agent.
Kaempferol, a natural flavonoid present in several plants, possesses a wide range of therapeutic properties such as antioxidant, anticancer, and anti‐inflammatory. It has a significant role in ...reducing cancer and can act as a therapeutic agent in the treatment of diseases and ailments such as diabetes, obesity, cardiovascular diseases, oxidative stress, asthma, and microbial contamination disorders. Kaempferol acts through different mechanisms: It induces apoptosis (HeLa cervical cancer cells), decreases cell viability (G2/M phase), downregulates phosphoinositide 3‐kinase (PI3K)/AKT (protein kinase B) and human T‐cell leukemia/lymphoma virus‐I (HTLV‐I) signaling pathways, suppresses protein expression of epithelial‐mesenchymal transition (EMT)‐related markers including N‐cadherin, E‐cadherin, Slug, and Snail, and metastasis‐related markers such as matrix metallopeptidase 2 (MMP‐2). Accordingly, the aim of the present review is to collect information pertaining to the effective role of kaempferol against various degenerative disorders, summarize the antioxidant, anti‐inflammatory, anticancer, antidiabetic, and antiaging effects of kaempferol and to review the progress of recent research and available data on kaempferol as a protective and chemotherapeutic agent against several ailments.
Au/Pd octopods and concave core@shell Au@Pd nanocrystals have been prepared by coupling for the first time a seed-mediated synthetic method with co-reduction. The integration of these two methods is ...central to the formation of these binary Au/Pd nanocrystals wherein the kinetics of seeded growth are manipulated via the co-reduction technique to control the final morphology of the nanocrystals. Significantly, the synthesis of these structures under similar reaction conditions illustrates that they are structurally related kinetic products. Detailed characterization by STEM-EDX analysis highlights the unique structural features of these nanocrystals and indicates that Pd localizes on the higher-energy features of the nanocrystals. Optical and electrocatalytic characterization also demonstrates their promise as a new class of multifunctional nanostructures.
•Complete dechlorination of DDT occurs at silver electrodes in DMF and DMF–H2O.•Aliphatic chlorines of DDT are cleaved more readily at silver than at carbon cathodes.•Voltammograms at 100mV s−1 show ...four prominent cathodic peaks for DDT at Ag in DMF.•DDT degrades via direct cleavage of C–Cl bonds and base-catalyzed elimination of Cl−.
Cyclic voltammetry and controlled-potential (bulk) electrolysis have been employed to investigate the reduction of 4,4′-(2,2,2-trichloroethane-1,1-diyl)bis(chlorobenzene) (DDT) at silver cathodes in dimethylformamide (DMF) containing 0.050M tetramethylammonium tetrafluoroborate (TMABF4). In addition, this work has been extended to the individual reductions of two degradation products, namely 4,4′-(2,2-dichloroethane-1,1-diyl)bis(chlorobenzene) (DDD) and 4,4′-(ethene-1,1-diyl)bis(chlorobenzene) (DDNU). At a scan rate of 100mV s−1, cyclic voltammograms for irreversible reduction of DDT at a silver electrode exhibit four prominent cathodic peaks in DMF and CH3CN, and three prominent cathodic peaks in DMSO. On the other hand, reduction of DDD and DDNU at silver in DMF–0.050M TMABF4 displays four and two irreversible peaks, respectively. Carbon–chlorine bonds of the –CCl3 moiety of DDT and of the –CHCl2 moiety of DDD are reduced more easily at silver than at glassy carbon. Bulk electrolyses of DDT at a silver gauze cathode in DMF–0.050M TMABF4 afford a potential-dependent mixture of products that includes DDD, DDNU, 4,4′-(2,2-dichloroethene-1,1-diyl)bis(chlorobenzene) (DDE), 4,4′-(2-chloroethene-1,1-diyl)bis(chlorobenzene) (DDMU), 4,4′-(2-chloroethane-1,1-diyl)bis(chlorobenzene) (DDMS), 1-chloro-4-(1-phenylvinyl)benzene (PVB), 1,1′-diphenylethylene (DPE), and 1,1′-ethylidenebisbenzene (EBB). However, at more negative potentials, the principal products are completely dechlorinated DPE and EBB. Dechlorination of DDT at silver appears to proceed via a series of steps involving carbanion intermediates arising from direct reduction of alkyl and aryl carbon–chlorine bonds along with hydroxide-promoted E2 elimination of chloride. When DMF-d7 was used as solvent, no evidence for deuterium atom incorporation into any product was seen, which indicates that radical intermediates do not play a significant role in the reduction of DDT.
Summary
Ships and icebergs are similar in size and intensity in SAR images, so it is difficult to distinguish them in remote sensing images. Deep learning is a technique based on neural networks, ...which has played an important role in image information processing. In order to address the challenge of ship and iceberg classification, we present a convolutional neural network (CNN) based classification method for iceberg and ship discrimination from Sentinel‐1 SAR images with different polarizations and incidence angles. The method is based on the fixed constant false alarm rate (CFAR) detector and the CNN model has three input channels, then the model was trained using parallel algorithm. The CNN is trained using 1443 images and tested using 161 images. The CNN model is also compared with support vector machine (SVM) and k nearest neighbors (kNN) using the same dataset. Comparison shows the CNN‐based method performs the best, and it achieved a validation accuracy of 96%.
Abstract
The androgen receptor (AR) is the master regulator of prostate cancer (PCa) development, and inhibition of AR signalling is the most effective PCa treatment. AR is expressed in PCa cells and ...also in the PCa-associated stroma, including infiltrating macrophages. Macrophages have a decisive function in PCa initiation and progression, but the role of AR in macrophages remains largely unexplored. Here, we show that AR signalling in the macrophage-like THP-1 cell line supports PCa cell line migration and invasion in culture via increased Triggering Receptor Expressed on Myeloid cells-1 (TREM-1) signalling and expression of its downstream cytokines. Moreover, AR signalling in THP-1 and monocyte-derived macrophages upregulates IL-10 and markers of tissue residency. In conclusion, our data suggest that AR signalling in macrophages may support PCa invasiveness, and blocking this process may constitute one mechanism of anti-androgen therapy.
Nitrogen-doped graphitic carbon has been intensively studied for potential use as an electrocatalyst in fuel cells for the oxygen reduction reaction (ORR). However, the lack of a mechanistic ...understanding on the carbon catalysis has severely hindered the progress of the catalyst development. Herein we use a well-defined graphene nanostructure as a model system and, for the first time, reveal an oxygen activation mechanism that involves carbanion intermediates in these materials. Our work shows that the overpotential of the electrocatalytic ORR is determined by the generation of the carbanion intermediates, and the current by the rate the intermediates activate oxygen.
Gastroenteropancreatic neuroendocrine carcinoma (GEP-NEC) is a poorly understood disease with limited treatment options. A better understanding of this disease would greatly benefit from the ...availability of representative preclinical models. Here, we present the potential of tumor organoids, three-dimensional cultures of tumor cells, to model GEP-NEC. We established three GEP-NEC organoid lines, originating from the stomach and colon, and characterized them using DNA sequencing and immunohistochemistry. Organoids largely resembled the original tumor in expression of synaptophysin, chromogranin and Ki-67. Models derived from tumors containing both neuroendocrine and non-neuroendocrine components were at risk of overgrowth by non-neuroendocrine tumor cells. Organoids were derived from patients treated with cisplatin and everolimus and for the three patients studied, organoid chemosensitivity paralleled clinical response. We demonstrate the feasibility of establishing NEC organoid lines and their potential applications. Organoid culture has the potential to greatly extend the repertoire of preclinical models for GEP-NEC, supporting drug development for this difficult-to-treat tumor type.
► Cyclic voltammograms for reduction of Lindane at silver exhibit one irreversible peak. ► Reduction of Lindane at silver leads exclusively to benzene in aqueous–organic media. ► Formation of benzene ...via reduction of Lindane at silver is a six-electron process. ► Chlorobenzene cannot be reduced at silver in organic or aqueous–organic media.
In the present work, the electrocatalytic ability of a silver cathode to dechlorinate Lindane (1R,2r,3S,4R,5r,6S-hexachlorocyclohexane) in acetonitrile (ACN), dimethylformamide (DMF), ethanol (EtOH), and 50:50 organic–water mixtures (by volume), each containing 0.050M tetra-n-butylammonium tetrafluoroborate (TBABF4) as supporting electrolyte, has been investigated with the aid of cyclic voltammetry and controlled-potential (bulk) electrolysis. For each solvent system, a cyclic voltammogram for direct reduction of Lindane exhibits a single cathodic peak at a silver electrode with a peak potential (vs. a saturated calomel electrode, SCE) of −1.40V (ACN), −1.43V (DMF), −1.50V (EtOH), −0.89V (50:50 ACN–H2O), −0.94V (50:50 DMF–H2O), and −0.90V (50:50 EtOH–H2O). Bulk electrolytic reduction of Lindane at a silver gauze cathode, held at a potential that is 150mV more negative than each of the preceding peak potentials, affords predominantly benzene (60–100% yield) in a six-electron process; however, in a pure ACN or EtOH medium, chlorobenzene is found in significant yield after an electrolysis. When bulk reduction of Lindane is carried out in pure ACN at a potential 350mV more negative than the peak potential, no chlorobenzene is detected. Pentachlorocyclohexene, tetrachlorocyclohexene, three isomers of trichlorobenzene, and three isomers of dichlorobenzene have been identified as intermediates in the reduction of Lindane in ACN. Reduction of Lindane involves a combination of one- and two-electron cleavage of carbon–chlorine bonds. Due to its ability to serve as an effective proton donor, water (when added to ACN, DMF, and EtOH) promotes the complete conversion of Lindane to benzene.
PDF
