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61.
This review deals with the historical discovery of particularly important lignan derivatives used in cancer chemotherapy. From isolation of the naturally occurring podophyllotoxin, an inhibitor of microtubule assembly, to hemisynthesis of the clinically important anticancer drugs etoposide and teniposide, it will be demonstrated how the activities and the ability of this class of compounds to inhibit topoisomerase II were discovered by different research teams. By virtue of these discoveries, new hemisynthetic derivatives, with different mechanisms of action, are bringing improvements in the ability to treat cancer. 相似文献
62.
In this paper, the problem of undesirable photonuclear, electronuclear and neutron capture reactions taking place in the treatment room during emission of the typical high-energy therapeutic beams from two different medical accelerators, i.e. Primus Siemens and Varian Clinac-2300, is presented. The radioisotopes (187)W, (56)Mn, (28)Al, (57)Ni, (38)Cl, (57)Co and (19)Au and the neutron activation of (1)H were identified as a consequence of these reactions. Moreover, the increased photon fluence rate behind the door of the accelerator bunker in the operator console room was observed during emission of the 20 MV X-rays from the Varian Clinac-2300 as well as in the case of the 15 MV X-ray beam from the Primus Siemens. No increased radiation was observed during the 6 MV X-ray beam emission. The performed measurements produced evidences on the presence of neutrons in the operator console room during emission of the 15 MV X-ray beam from the Primus Siemens as well as the 20 MV X-rays and the 22 MeV electrons from the Varian Clinac-2300 accelerator. 相似文献
63.
Kinga Kska Micha Wojciech Szczeniak Adela Adamus Magorzata Czernicka 《International journal of molecular sciences》2021,22(15)
Low oxygen level is a phenomenon often occurring during the cucumber cultivation period. Genes involved in adaptations to stress can be regulated by non-coding RNA. The aim was the identification of long non-coding RNAs (lncRNAs) involved in the response to long-term waterlogging stress in two cucumber haploid lines, i.e., DH2 (waterlogging tolerant—WL-T) and DH4 (waterlogging sensitive—WL-S). Plants, at the juvenile stage, were waterlogged for 7 days (non-primed, 1xH), and after a 14-day recovery period, plants were stressed again for another 7 days (primed, 2xH). Roots were collected for high-throughput RNA sequencing. Implementation of the bioinformatic pipeline made it possible to determine specific lncRNAs for non-primed and primed plants of both accessions, highlighting differential responses to hypoxia stress. In total, 3738 lncRNA molecules were identified. The highest number (1476) of unique lncRNAs was determined for non-primed WL-S plants. Seventy-one lncRNAs were depicted as potentially being involved in acquiring tolerance to hypoxia in cucumber. Understanding the mechanism of gene regulation under long-term waterlogging by lncRNAs and their interactions with miRNAs provides sufficient information in terms of adaptation to the oxygen deprivation in cucumber. To the best of our knowledge, this is the first report concerning the role of lncRNAs in the regulation of long-term waterlogging tolerance by priming application in cucumber. 相似文献
64.
Dietary licorice root supplementation reduces diet‐induced weight gain,lipid deposition,and hepatic steatosis in ovariectomized mice without stimulating reproductive tissues and mammary gland 下载免费PDF全文
Zeynep Madak‐Erdogan Ping Gong Yiru Chen Zhao Liwen Xu Kinga U. Wrobel James A. Hartman Michelle Wang Anthony Cam Urszula T. Iwaniec Russell T. Turner Nathan C. Twaddle Daniel R. Doerge Ikhlas A. Khan John A. Katzenellenbogen Benita S. Katzenellenbogen William G. Helferich 《Molecular nutrition & food research》2016,60(2):369-380
65.
Unocic Kinga A. Shin Dongwon Unocic Raymond R. Allard Lawrence F. 《Oxidation of Metals》2017,88(3-4):495-508
Oxidation of Metals - The nanoscale oxidation mechanisms and kinetics of a model β-NiAl system were investigated using in situ closed-cell gas reaction scanning transmission electron... 相似文献
66.
Jan Bergholz Bruce A. Pint Kinga A. Unocic Robert Vaßen 《Journal of Thermal Spray Technology》2017,26(5):868-879
Nanoscale oxide dispersions have long been used to increase the oxidation and wear resistance of alloys used as bond coatings in thermal barrier coatings. Their manufacturing via mechanical alloying is often accompanied by difficulties regarding their particle size, homogeneous distribution of the oxide dispersions inside the powder, involving considerable costs, due to cold welding of the powder during milling. A significant improvement in this process can be achieved by the use of process control agent (PCA) to achieve the critical balance between cold welding and fracturing, thereby enhancing the process efficiency. In this investigation, the influence of the organic additive stearic acid on the manufacturing process of Al2O3-doped CoNiCrAlY powder was investigated. Powders were fabricated via mechanical alloying at different milling times and PCA concentrations. The results showed a decrease in particle size, without hindering the homogeneous incorporation of the oxide dispersions. Two powders manufactured with 0.5 and 1.0 wt.% PCA were deposited by high velocity oxygen fuel (HVOF) spraying. Results showed that a higher content of elongated particles in the powder with the higher PCA content led to increased surface roughness, porosity and decreased coating thickness, with areas without embedded oxide particles. 相似文献
67.
Katarzyna Solarska-
ciuk Kinga Adach Mateusz Fijakowski Katarzyna Haczkiewicz-Leniak Micha Kulus Mateusz Olbromski Natalia Glatzel-Pluciska Oskar Szelest Dorota Bonarska-Kujawa 《International journal of molecular sciences》2022,23(9)
The term “nanosilica” refers to materials containing ultrafine particles. They have gained a rapid increase in popularity in a variety of applications and in numerous aspects of human life. Due to their unique physicochemical properties, SiO2 nanoparticles have attracted significant attention in the field of biomedicine. This study aimed to elucidate the mechanism underlying the cellular response to stress which is induced by the exposure of cells to both biogenic and pyrogenic silica nanoparticles and which may lead to their death. Both TEM and fluorescence microscopy investigations confirmed molecular changes in cells after treatment with silica nanoparticles. The cytotoxic activity of the compounds and intracellular RNS were determined in relation to HMEC-1 cells using the fluorimetric method. Apoptosis was quantified by microscopic assessment and by flow cytometry. Furthermore, the impact of nanosilica on cell migration and cell cycle arrest were determined. The obtained results compared the biological effects of mesoporous silica nanoparticles extracted from Urtica dioica L. and pyrogenic material and indicated that both types of NPs have an impact on RNS production causing apoptosis, necrosis, and autophagy. Although mesoporous silica nanoparticles did not cause cell cycle arrest, at the concentration of 50 μg/mL and higher they could disturb redox balance and stimulate cell migration. 相似文献
68.
69.
Cecilie V.Funch Alessandro Palmas Kinga Somlo Emilie H.Valente Xiaowei Cheng Konstantinos Poulios Matteo Villa Marcel A.J.Somers Thomas L.Christiansen 《材料科学技术学报》2021,81(22):67-76
Laser powder bed fusion (L-PBF) was utilized to produce specimens in Ti-6Al-4V,which were subjected to a bi-lamellar heat treatment,which produces microstructures consisting of primary α-lamellae and a fine secondary α-phase inside the inter-lamellar β-regions.The bi-lamellar microstructure was obtained as (i)a direct bi-lamellar heat treatment from the asbuilt condition or (ii) a bi-lamellar heat treatment preceded by a β-homogenization.For the bi-lamellar treatment with β-homogenization,cooling rates in the range 1-500 K/min were applied after homogenization in β-region followed by inter-critical annealing in the α + β region at various temperatures in the range 850-950 ℃.The microstructures were characterized using various microscopical techniques.Mechanical testing with Vickers hardness indentation and tensile testing was performed.The bi-lamellar microstructure was harder when compared to a soft fully lamellar microstructure,because of the presence of fine α-platelets inside the β-lamellae.Final low temperature ageing provided an additional hardness increase by precipitation hardening of the primary α-regions.The age hardened bi-lamellar microstructure shows a similar hardness as the very fine,as-built martensitic microstructure.The bi-lamellar microstructure has more favorable mechanical properties than the as-built condition,which has high strength,but poor ductility.After the bi-lamellar heat treatment,the elongation was improved by more than 250 %.Due to the very high strength of the as-built condition,loss of tensile strength is unavoidable,resulting in a reduction of tensile strength of~18 %. 相似文献
70.
Kinga Dobolyi Elizabeth Soechting Westley Weimer 《International Journal on Software Tools for Technology Transfer (STTT)》2011,13(2):111-129
Web-based applications are one of the most widely used types of software, and have become the backbone of many e-commerce
and communications businesses. These applications are often mission-critical for many organizations, motivating their precise
validation. Although regression testing has been widely used to gain confidence in the reliability of software by providing
information about the quality of an application, it has suffered limited use in this domain due to the frequent nature of
updates to websites and the difficulty of automatically comparing test case output. We present techniques to address these
challenges in regression testing web-based applications. Without precise comparators, test cases that fail due to benign program
evolutions must be manually inspected. Our approach harnesses the inherent similarities between unrelated web-based applications
to provide fully automated solutions to reduce the number of such false positives, while simultaneously returning true faults.
By applying a model derived from regression testing other programs, our approach can predict which test cases merit human
inspection. Our method is 2.5 to 50 times as accurate as current industrial practice, but requires no user annotations. 相似文献