Search results for "two-dimensional"

Cytotoxic neo-clerodane diterpenes from Stachys aegyptiaca

2018

Abstract Two new E/Z neo-clerodane diterpene isomers, trivially named stachaegyptin D (1) and E (2), together with known compounds, stachysolon monoacetate (3) and stachysolon diacetate (4), were isolated from an organic-solvent extract of the medicinal herb Stachys aegyptiaca. Structures were elucidated by a combination of spectroscopic methods, including HREIMS, 1H, 13C, DEPT, and 2D NMR analysis, as well as, first time X-ray analysis for stachysolone (3). All isolated metabolites showed some activity against the human hepatocellular cell line, HepG2. Compound 4 was the most active with an IC50 of 59.5 μM.

Proteomic profiling of Trastuzumab (Herceptin(R))-sensitive and -resistant SKBR-3 breast cancer cells.

2013

BACKGROUND: The Human Epidermal Growth Factor Receptor 2 (HER-2), overexpressed in 25-30% of breast carcinomas (BC), is the therapeutic target for trastuzumab, a recombinant humanized monoclonal antibody. The initial response to trastuzumab is often followed by drug-insensitivity within one year. Several hypotheses have been raised to explain this event, but the mechanisms behind the responses to trastuzumab are still unclear. Aim: To study the effects of short and prolonged trastuzumab treatment on the proteomic profiles of HER-2-overexpressing SKBR-3 BC cells. MATERIALS AND METHODS: Cells were treated with trastuzumab to obtain sensitive and resistant clones. The drug effects were evaluat…

Antileukemic ancistrobenomine B and related 5,1′-coupled naphthylisoquinoline alkaloids from the Chinese liana Ancistrocladus tectorius

2017

A striking feature of the metabolite pattern of the Southeast Asian liana Ancistrocladus tectorius (Ancistrocladaceae) is the predominance of 5,1′-coupled naphthylisoquinoline alkaloids. About 20 alkaloids of this coupling type have so far been discovered in this plant species. Here, we report on the isolation of four new 5,1′-linked naphthylisoquinolines from the twigs and stems of A. tectorius. Two of them, the ancistrobenomines B (5) and C (6), belong to the very rare group of alkaloids with a fully dehydrogenated isoquinoline portion. Likewise unusual for naphthylisoquinoline alkaloids is the presence of a hydroxymethylene group at C-3. Within the large class of meanwhile ca. 180 such n…

Antiproliferative activity against leukemia cells of sesquiterpene lactones from the Turkish endemic plant Centaurea drabifolia subsp. detonsa

2017

The apolar organic extract obtained from aerial parts of Centaurea drabifolia Sibth. & Sm. subsp. detonsa (Bornm.) Wagenitz, growing wild in Turkey, was investigated for the first time for its secondary metabolite composition. Seven sesquiterpene lactones belonging to the guaiane class (1-7), including the new compound 4, along with a fatty acid lactone derivative (8), were isolated. The structures of these compounds were established by spectroscopic analysis, including 2D NMR spectroscopic techniques, with the stereostructure of the new guaiane 4 determined with the help of MTPA derivatization. Cytotoxic activities of compounds 1-7 were evaluated against two cancer cell lines, namely acute…

Two-dimensional electrophoresis analysis of proteins extracted from leaves of homozygous and heterozygous citrus

2011

Two-Dimensional Crystals and van der Waals Heterostructures based on Inorganic and Molecular Strongly Correlated Layered Materials

2021

“En resumen, toda obra grande es el fruto de la paciencia y de la perseverancia, combinadas con una atención orientada tenazmente durante meses y aun años hacia un objeto particular”. “In summary, all great work is the fruit of patience and perseverance, combined with tenacious concentration on a subject over a period of months or years”. Santiago Ramón y Cajal (Reglas y consejos sobre investigación científica. Madrid: Academia de Ciencias Exactas, Físicas y Naturales, 1897). The present Thesis constitutes a journey –a romance of many dimensions, quoting Edwin Abbot Abbot– from 3D to 2D and, hopefully (we let the curious Reader judge), “Through Flatland to Thoughtland” (citing, again, Abbot…

Expression of phase-specific haemolymph polypeptides in a laboratory strain and field catches of Schistocerca gregaria.

2003

Uvarov's theory of locust phase polymorphism implies a differential phase-specific gene expression. It was the goal of the present investigation to provide data on the molecular level for this concept. We used the technique of 2D gel electrophoresis to generate haemolymph polypeptide maps from mature locust males. Under the given conditions we identified 238 polypeptide spots by their molecular weight and isoelectrical point. Isolated and crowded males from the Mainz strain, all originating from crowded ancesters, differed in 20 spots: three were solitary-specific and 17 crowded-specific. Field catches of solitary and gregarious S. gregaria in Mauritania revealed that those males showed the…

Supramolecular self-assembly on the B-Si(111)-(√3x√3) R30° surface: From single molecules to multicomponent networks

2017

Abstract Understanding the physical and chemical processes in which local interactions lead to ordered structures is of particular relevance to the realization of supramolecular architectures on surfaces. While spectacular patterns have been demonstrated on metal surfaces, there have been fewer studies of the spontaneous organization of supramolecular networks on semiconductor surfaces, where the formation of covalent bonds between organics and adatoms usually hamper the diffusion of molecules and their subsequent interactions with each other. However, the saturation of the dangling bonds at a semiconductor surface is known to make them inert and offers a unique way for the engineering of m…

$O(n^2 log n)$ Time On-line Construction of Two-Dimensional Suffix Trees

2007

The two-dimensional suffix tree of an n × n square matrix A is a compacted trie that represents all square submatrices of A [11]. For the off-line case, i.e., A is given in advance to the algorithm, it is known how to build it in optimal time, for any type of alphabet size [11], [18]. Motivated by applications in Image Compression [22], Giancarlo and Guaiana [14] considered the on-line version of the two-dimensional suffix tree and presented an O(n2 log2 n)-time algorithm, which we refer to as GG. That algorithm is a nontrivial generalization of Ukkonen’s on-line algorithm for standard suffix trees [23]. The main contribution in this paper is an O(logn) factor improvement in the time comple…

Bio-vaterite formation by glycoproteins from freshwater pearls

2010

Abstract A 48 kDa acidic and putative calcium-binding glycoprotein was isolated from pearls of the freshwater mussel Hyriopsis cumingii . This protein was compared with a related 46 kDa polypeptide, obtained from the nacreous shell of the same species. Separation by two-dimensional gel electrophoresis revealed that the difference in molecular weight is due to the higher extent of glycosylation of the 48 kDa protein existing in pearls. Evidence is presented that the sugar moieties of the protein contribute to crystal growth, starting with the nucleation step. In in vitro precipitation experiments, the 48 kDa glycoprotein of pearls directed the formation of round-shaped vaterite crystals whil…