1,767 research outputs found
Novel polyamide amidine anthraquinone platinum(II) complexes: cytotoxicity, cellular accumulation, and fluorescence distributions in 2D and 3D cell culture models
1- and 1,5-Aminoalkylamine substituted anthraquinones (AAQs, 1C3 and 1,5C3) were peptide coupled to 1-, 2-, and 3-pyrrole lexitropsins to generate compounds that incorporated both DNA minor groove and intercalating moieties. The corresponding platinum(II) amidine complexes were synthesized through a synthetically facile amine-to-platinum mediated nitrile 'Click' reaction. The precursors as well as the corresponding platinum(II) complexes were biologically evaluated in 2D monolayer cells and 3D tumour cell models. Despite having cellular accumulation levels that were up to five-fold lower than that of cisplatin, the platinum complexes had cytotoxicities that were only three-fold lower. Accumulation was lowest for the complexes with two or three pyrrole groups, but the latter was the most active of the complexes exceeding the activity of cisplatin in the MDA-MB-231 cell line. All compounds showed moderate to good penetration into spheroids of DLD-1 cells with the distributions being consistent with active uptake of the pyrrole containing complexes in regions of the spheroids starved of nutrients
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In-street wind direction variability in the vicinity of a busy intersection in central London
We present results from fast-response wind measurements within and above a busy intersection between two street canyons (Marylebone Road and Gloucester Place) in Westminster, London taken as part of the DAPPLE (Dispersion of Air Pollution and Penetration into the Local Environment; www.dapple.org.uk) 2007 field campaign. The data reported here were collected using ultrasonic anemometers on the roof-top of a building adjacent to the intersection and at two heights on a pair of lamp-posts on opposite sides of the intersection. Site characteristics, data analysis and the variation of intersection flow with the above-roof wind direction (θref) are discussed. Evidence of both flow channelling and recirculation was identified within the canyon, only a few metres from the intersection for along-street and across-street roof-top winds respectively. Results also indicate that for oblique rooftop flows, the intersection flow is a complex combination of bifurcated channelled flows, recirculation and corner vortices. Asymmetries in local building geometry around the intersection and small changes in the background wind direction (changes in 15-min mean θref of 5–10 degrees) were also observed to have profound influences on the behaviour of intersection flow patterns. Consequently, short time-scale variability in the background flow direction can lead to highly scattered in-street mean flow angles masking the true multi-modal features of the flow and thus further complicating modelling challenges
Halogen ligth thermogravimetric technique for determining the retained water in fine aggregates used for concrete mixing design
[EN] Measuring the rate of water retention of the aggregates used in mortars and concrete is required to achieve a good mix design. The water retention, specifically absorption, is used to keep constant the water/cement ratio. This paper focuses on the study of a new technique for measuring retained water in fine aggregates. In order to obtain results, the procedure described in the existing standards takes more than 24 h. Additionally, it involves high consumption of heat energy due to the use of drying ovens. Furthermore, the results obtained remain highly variable and therefore discussed by the scientific community.In this research, a novel technique based on a halogen moisture analyzer was implemented. The technique was assessed using an experiment design with a surface response model. The most important factors and levels were identified together with the interactions between them. Finally, the model was validated and the results
obtained with this technique were compared with those obtained by conventional techniques in order to verify that they were equivalent.Arias Jaramillo, Y.; Paya Bernabeu, JJ.; Ochoa Botero, JC. (2015). Halogen ligth thermogravimetric technique for determining the retained water in fine aggregates used for concrete mixing design. Journal of Thermal Analysis and Calorimetry: an international forum for thermal studies. 123:127-134. doi:10.1007/s10973-015-4902-8S127134123Djerbi Tegguer A. Determining the water absorption of recycled aggregates utilizing hydrostatic weighing approach. Constr Build Mater. 2012;27:112–6.Kasemchaisiri R, Tangtermsirikul S. A method to determine water retainability of porous fine aggregate for design and quality control of fresh concrete. Constr Build Mater. 2007;21:1322–34.Gonilho Pereira C, Castro-Gomes J, Pereira de Oliveira L. Influence of natural coarse aggregate size, mineralogy and water content on the permeability of structural concrete. Constr Build Mater. 2009;23:602–8.Cortas R, RoiziĂ©re E, Staquet S, Hamami A, Delplancke-Ogletree M. Effect of the water saturation of aggregates on the shrinkage induced cracking risk of concrete at early age. Cem Concr Compos. 2014;50:1–9.Black R. The determination of specific gravity using Siphon-Can method. Cem Concr Aggreg. 1986;8:46–50.Saxer E. A direct method of determining absorption and specific gravity of aggregates. 1956;2.Hughes B, Famili H., Part 1—Absorption of concrete aggregates, Part 2—saturated air techniques for determining the absorption of aggregates. In: Absorptions of concrete aggregates. Birmingham University; 1971.Tam VWY, Gao XF, Tam CM, Chan CH. New approach in measuring water absorption of recycled aggregates. Constr Build Mater. 2008;22:364–9.Balcedowiak W. Phase analysis of high-calcium line by TG. J Therm Anal Calorim. 2000;60:70–7.Mendoza O, TobĂłn JI. An alternative thermal method for identification of pozzolanic activity in Ca(OH)2/pozzolan pastes. J Therm Anal Calorim. 2013;114:589–96.Kosmatka SH, Kerkhoff B, Panarese W, MacLeod NF, McGrath RJ, Design and control of concrete mixtures. 7rd ed. Cement association of Canada. 2002. pp. 88.Cárdenas JI, Restrepo C. Patrimonio geolĂłgico y patrimonio minero de la cuenca carbonĂfera del suroeste antioqueño, Colombia. BoletĂn de ciencias de la tierra. 2006;18:91–102 ISSN 0120-3630 .Klein NS, Aguado A, Tollares-Carbonari BM, Real LV. Prediction of the water absorption by aggregates over time: modelling through the use of value function and experimental validation. Constr Build Mater. 2014;69:213–20
Public views on principles for health care priority setting: findings of a European cross-country study using Q methodology
International audienc
Nutrition support in cancer patients: a brief review and suggestion for standard indications criteria
The indications of nutrition support in cancer patients have been subject to controversy. Most studies address the effects of the method in increasing the survival or the tumor response rate. Few studies have focused on the effects in improving quality of life. After a brief review, we described the results of a study, which evaluated the effects of protein-caloric supplementation on the quality of life parameters in a group of head and neck cancer patients submitted to radiotherapy. The results support the suggestion of creating standard criteria to indicate nutrition support in cancer patients. Based on our findings, nutrition support should be indicated for cancer patients considering the potential effects to improve the quality of life
Room temperature chiral magnetic skyrmion in ultrathin magnetic nanostructures
Magnetic skyrmions are chiral spin structures with a whirling configuration.
Their topological properties, nanometer size and the fact that they can be
moved by small current densities have opened a new paradigm for the
manipulation of magnetisation at the nanoscale. To date, chiral skyrmion
structures have been experimentally demonstrated only in bulk materials and in
epitaxial ultrathin films and under external magnetic field or at low
temperature. Here, we report on the observation of stable skyrmions in
sputtered ultrathin Pt/Co/MgO nanostructures, at room temperature and zero
applied magnetic field. We use high lateral resolution X-ray magnetic circular
dichroism microscopy to image their chiral N\'eel internal structure which we
explain as due to the large strength of the Dzyaloshinskii-Moriya interaction
as revealed by spin wave spectroscopy measurements. Our results are
substantiated by micromagnetic simulations and numerical models, which allow
the identification of the physical mechanisms governing the size and stability
of the skyrmions.Comment: Submitted version. Extended version to appear in Nature
Nanotechnolog
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Cosmogenic neutron production at the Sudbury Neutrino Observatory
Neutrons produced in nuclear interactions initiated by cosmic-ray muons present an irreducible background to many rare-event searches, even in detectors located deep underground. Models for the production of these neutrons have been tested against previous experimental data, but the extrapolation to deeper sites is not well understood. Here we report results from an analysis of cosmogenically produced neutrons at the Sudbury Neutrino Observatory. A specific set of observables are presented, which can be used to benchmark the validity of geant4 physics models. In addition, the cosmogenic neutron yield, in units of 10-4 cm2/(g·μ), is measured to be 7.28±0.09(stat)-1.12+1.59(syst) in pure heavy water and 7.30±0.07(stat)-1.02+1.40(syst) in NaCl-loaded heavy water. These results provide unique insights into this potential background source for experiments at SNOLAB
Constraints on Nucleon Decay via "Invisible" Modes from the Sudbury Neutrino Observatory
Data from the Sudbury Neutrino Observatory have been used to constrain the
lifetime for nucleon decay to ``invisible'' modes, such as n -> 3 nu. The
analysis was based on a search for gamma-rays from the de-excitation of the
residual nucleus that would result from the disappearance of either a proton or
neutron from O16. A limit of tau_inv > 2 x 10^{29} years is obtained at 90%
confidence for either neutron or proton decay modes. This is about an order of
magnitude more stringent than previous constraints on invisible proton decay
modes and 400 times more stringent than similar neutron modes.Comment: Update includes missing efficiency factor (limits change by factor of
2) Submitted to Physical Review Letter
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