Literature survey

About: Literature survey is a research topic. Over the lifetime, 15372 publications have been published within this topic receiving 459196 citations.

Chemistry, biology, and medicinal potential of narciclasine and its congeners.

Abstract: Ornamental flower growers know that placing a cut daffodil (a.k.a. narcissus) in a vase with other flowers has a negative effect on the quality of those flowers and significantly shortens their vase life. Furthermore, a common horticultural practice for the cultivation of narcissus flowers involves the introduction of cuts on the bulbs before immersing them into water. The mucilage that leaches out from the cuts is constantly removed by frequent changing of water and this leads to sprouting. These observations raise speculation that specific components in the mucilage of the narcissus bulbs may have powerful growth-inhibitory effects. Historical use of narcissus flowers, as well as at least thirty other plants of the Amaryllidaceae family, in folk medicine for the management of cancer1 speaks volumes to validate this conjecture. Indeed, powerful anticancer properties of Narcissus poeticus L. were already known to the Father of Medicine, Hippokrates of Kos (ca. B.C. 460–370), who recommended a pessary prepared from narcissus oil for the treatment of uterine tumors.2 His successors, the ancient Greek physicians Pedanius Dioscorides (ca. A.D. 40–90) and Soranus of Ephesus (A.D. 98–138) continued using this therapy in the first and second centuries A.D.3,4 In addition, the topical anticancer uses of extracts from this plant5,6 as well as from N. pseudonarcissus7–9 were recorded in the first century A.D. by the Roman natural philosopher Gaius Plinius Secundus, (A.D. 23–79), better known as Pliny the Elder.10 Even the Bible provides multiple references to the Mediterranean N. tazetta L., which has a long history of use against cancer.11 The applications of narcissus oil in cancer management continued in the middle ages in Chinese, North African, Central American and Arabian medicine.1,12 The uses of other genera of the Amaryllidaceae family were also common, e. g. Hymenocallis caribaea (L. emend Gawler) Herbert, utilized by early European medical practitioners for inflammatory tumors.13 More recently, the plants of the Amaryllidaceae have been under intense scrutiny for the presence of the specific metabolites responsible for the medicinal properties associated with this plant family. The study began in 1877 with the isolation of alkaloid lycorine from Narcissus pseudonarcissus14 and since then more than 100 alkaloids, exhibiting diverse biological activities, have been isolated from the Amaryllidaceae plants. Based on the present scientific evidence, it is likely that isocarbostyril constituents of the Amaryllidaceae, such as narciclasine, pancratistatin and their congeners, are the most important metabolites responsible for the therapeutic benefits of these plants in the folk medical treatment of cancer. Notably, N. poeticus L. used by the ancient Greek physicians, as was eluded before, is now known to contain some 0.12 g of narciclasine per kg of fresh bulbs.15 Continuing along this intriguing path, the focus of the present review is a comprehensive literature survey and discussion of the chemistry and biology of these compounds as specifically relevant to their potential use in medicine. The examination of the synthetic organic chemistry, more specifically the total synthesis efforts inspired by the challenging chemical structures of narciclasine, pancratistatin and their congeners, will be reduced to a minimum in view of the two very recent excellent reviews published on this subject.16,17

The dissolution and biological effects of silver nanoparticles in biological media

Abstract: Silver ions and silver nanoparticles have a well-known biological effect that typically occurs in biological or environmental media of complex composition. Silver nanoparticles release silver ions if oxidizing species like molecular oxygen or hydrogen peroxide are present. The presence of glucose as a model for reducing sugars has only a small effect on the dissolution rate. In the presence of chloride ions, precipitation of silver chloride nanoparticles occurs. At physiological salt concentrations, no precipitation of silver phosphate occurs as the precipitation of silver chloride always occurs first. If the surface of a silver nanoparticle is passivated by cysteine, the dissolution is quantitatively inhibited. Upon immersion of silver nanoparticles in pure water for 8 months, leading to about 50% dissolution, no change in the surface was observed by transmission electron microscopy. A model for the dissolution was derived from immersion and dissolution experiments in different media and from high-resolution transmission electron microscopy. A literature survey on the available data on the dissolution of silver nanoparticles showed that only qualitative trends can be identified as the nature of the nanoparticles and of the immersion medium are practically never comparable. The dissolution effects were confirmed by cell culture experiments (human mesenchymal stem cells and neutrophil granulocytes) where silver nanoparticles that were stored under argon had a clearly lower cytotoxicity than those stored under air. They also led to a less formation of reactive oxygen species (ROS). This underscores that silver ions are the toxic species.

Review of flash sintering: materials, mechanisms and modelling

Abstract: Flash sintering (FS) is an energy efficient sintering technique involving electrical Joule heating, which allows very rapid densification (<60 s) of particulate materials. Since the first publication on flash-sintered zirconia (3YSZ) in 2010, it has been intensively researched and applied to a wide range of materials. Going back more than a century ago, we have found a close similarity between FS of oxides and Nernst glowers developed in 1897. This review provides a comprehensive overview of FS and is based on a literature survey consisting of 88 papers and seven patents. It correlates processing parameters (i.e. electric field magnitude, current density, waveforms (AC, DC) and frequency, furnace temperature, electrode materials/configuration, externally applied pressure and sintering atmosphere) with microstructures and densification mechanisms. Theorised mechanisms driving the rapid densification are substantiated by modelling work, advanced in situ analysis techniques and by established theorie...

A survey of traceability in requirements engineering and model-driven development

Abstract: Traceability--the ability to follow the life of software artifacts--is a topic of great interest to software developers in general, and to requirements engineers and model-driven developers in particular. This article aims to bring those stakeholders together by providing an overview of the current state of traceability research and practice in both areas. As part of an extensive literature survey, we identify commonalities and differences in these areas and uncover several unresolved challenges which affect both domains. A good common foundation for further advances regarding these challenges appears to be a combination of the formal basis and the automated recording opportunities of MDD on the one hand, and the more holistic view of traceability in the requirements engineering domain on the other hand.