Search results for "Ang"

3,3?,5,5?-Tetramethylbenzidme for the colorimetric determination of manganese in water

1998

Manganese can be determined by colorimetry with previous oxidation of Mn(II) in a strong basic medium, using 3,3′,5,5′-tetramethylbenzidine as a chromogenic reagent. The molar absorptivity of the reaction product is 3.4 × 104 mol−1l cm−1l, the detection limit 3 ng/ml, the RSD (0.5 mg/l,n = 8) 0.9% and the calibration range (1-cm cells) 0.02–0.8 mg/1 V(V), Cr(VI) and Co(II) are the most significant interferences. The new method was compared with an AAS procedure (air-acetylene flame) with previous solvent extraction and also with a colorimetric method for the determination of manganese in sea and drinking water.

Post-Processing via Cation Exchange Cartridges: Versatile Options

2012

New 68Ge/68Ga radionuclide generators provide the positron emitter 68Ga (T½ = 67.7 min) as an easily available and relatively inexpensive source of a PET nuclide for labeling of interesting targeting vectors. However, currently available “ionic” 68Ge/68Ga radionuclide generators are not necessarily optimized for the routine synthesis of 68Ga-labeled radiopharmaceuticals in a clinical environment. Post-processing of 68Ge/68Ga generators using cation exchange resins provides chemically and radiochemically pure 68Ga with 97±2% within less than 4 min, with 68Ge almost completely removed, and ready for online labeling. This simple, fast, and efficient technology can be extended for new applicati…

Synthesis and support composition effects on CH4 partial oxidation over Ni–CeLa oxides

2015

Abstract Two series of Ni (6 wt%) catalysts supported over CeO 2 , La 2 O 3 and mixed CeO 2 –La 2 O 3 were prepared by co-precipitation and by wet-impregnation. The effect of the two Ni loading procedures on the catalyst structural properties was investigated by XRD, TPR and XPS. The catalytic behavior of the catalysts was tested in the methane partial oxidation reaction performed at 1 atm in a temperature range of 400–800 °C using dilute feed gas mixture with CH 4 /O 2  = 2 and gas hourly space velocity of 60,000 ml g −1  h −1 . Total methane combustion was observed within the 450 °C ≤  T ≤ 650 °C temperature range. Above 650 °C partial oxidation of methane started to occur, reaching at 80…

Continuum Monte Carlo simulation of phase transitions in rod-like molecules at surfaces

1994

Stiff rod-like chain molecules with harmonic bond length potentials and trigonometric bond angle potentials are used to model Langmuir monolayers at high densities. One end of the rod-like molecules is strongly bound to a flat two-dimensional substrate which represents the air-water interface. A ground-state analysis is performed which suggests phase transitions between phases with and without collective uniform tilt. Large-scale off-lattice Monte Carlo simulations over a wide temperature range show in addition to the tilting transition the presence of a strongly constrained melting transition at high temperatures. The latter transition appears to be related to two-dimensional melting of th…

Erratum: The runaway instability of thick discs around black holes - II. Non-constant angular momentum discs

2004

Parametric assessment of myocardial perfusion by densitometric evaluation of digital subtraction coronary angiograms: a comparison with tomographic T…

2002

Densitometric results about local myocardial perfusion are compared with those derived from a quantitative analysis of TL-201 single photon emission computer tomograms (TL-201 SPECT). Ten patients underwent conventional TL-201 SPECT at rest and after maximum bicycle stress and dipyridamole infusion the day prior to the investigation. SPECT was applied to provide improved spatial resolution for the detection of perfusion abnormalities. During the catheterization procedure four digital subtraction coronary angiograms were performed, two of the left and two of the right coronary artery both before and after pharmacologically induced hyperemia by intracoronary papaverine. The densitometric para…

Simulations of Array Configurations for the Square Kilometre Array (SKA)

2010

The Square Kilometre Array (SKA) is a new generation radio telescope for the next decades, working at metre to centimetre wavelengths. The SKA will be operational at the same time than other new optical, X-ray and Gamma-ray telescopes. It is of extreme importance that the SKA becomes competitive and complementary to those instruments. An extensive study of technologies and possible configurations involved is needed to ensure the SKA will reach the design specifications. To compare imaging capabilities between different SKA configurations or between the SKA and other instruments, we have implemented figures of merit based on several characteristics of these instruments. In this work we are p…

Automatic generation of emissivity maps on a European scale

2009

The remote sensing measurement of the land surface temperature from satellites provides an overview of this magnitude on a continuous and regular basis. The study of its evolution in time and space is a critical factor in many scientific fields such as weather forecasting, detection of forest fires, climate change, and so on. The main problem of making this measurement from satellite data is the need to correct the effects of the atmosphere and the surface emissivity. In this work, these corrections have been made using a split-window algorithm. The aim was to define an enhanced vegetation cover method and develop a system that used it, in order to automatically generate maps of land surfac…

2017

By the possession of unique exocrine scent glands, Opiliones (harvestmen) arise as a perfect model for studies on the evolutionary history of secretion chemistry. Among gland compounds of harvestmen, it is the quinones that represent recurring elements across the secretions of all suborders. Reliable data on quinone-distribution, however, is only known for Laniatores (benzoquinones) and Cyphophthalmi (naphthoquinones). We here unraveled the quinone-distribution across scent gland secretions of the third large harvestman suborder, the Palpatores (= Eu- and Dyspnoi): Naphthoquinones were found in phalangiid Eupnoi across all subfamilies as well as in nemastomatid (and at least one ischyropsal…

Professor Dr Med Oskar Fehr: the fate of an outstanding German-Jewish ophthalmologist: an early contributor to cornea and external disease.

2014

PURPOSE The aim of this study was to recount the immense and abrupt change in the private and professional life of a prominent German-Jewish ophthalmologist in the transition from democracy to dictatorship in Germany during the first half of the 20th century. METHODS This involves a Retrospective analysis of Fehr's clinical and scientific work as the first assistant of Julius Hirschberg's world-famous eye clinic in Berlin; evaluation of Fehr's successful tenure as a chair of Virchow's Eye Hospital; the catastrophic influence of Hitler's seizure of power on the private and professional lives of German-Jewish physicians; and an analysis of Fehr's personal and professional will to continue the…