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Distribution by Scientific Domains

Chemistry	83%

Selected Abstracts

Small-scale production and storage quality of dry-milled degermed maize products for tropical countries

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2003
Christian Mestres
Summary A small-scale, single operation, dry degerminator, originating from Brazil was tested on six maize samples (from France and Mali) at two moisture contents (10 and 15% wb). The yield of brewery maize grits (<1% lipids) was higher for extensively dry (10% mc) and hard grains. It ranged from 50 to 70% for four cultivars, which was equivalent or higher than for industrial plants. The rancidity of the products was controlled by the fat acidity level, which was 40,60 mg KOH 100 g,1db, after 4 months storage of degermed flour. This indicates that degermed products can be stored at 35 °C for up to 6 months without developing significant rancid off-flavour. Thus the Brazilian dry degerminator appears suitable for the treatment of maize in the tropical zone of Africa. [source]

Expanding the Suzuki,Heck-Type Coupling Cascade: A New Indeno[1,2,3]-Annelation of Polycyclic Aromatic Hydrocarbons

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2009
Jennifer
Abstract Fluoranthene derivatives can be constructed in a single operation by a palladium-catalyzed cascade reaction sequence, starting from a peri -dichloronaphthalene derivative and various arylboronic acids. [source]

Global fractionation of oak heartwood extractable polymers (lignins, polysaccharides and ellagitannins) by selective precipitations

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 3 2005
Marie-Françoise Nonier
Abstract This paper introduces a new fractionation method by selective extractions and precipitations making it possible to collect the three groups of oak heartwood extractable polymers in a single operation. The three families, lignins, polysaccharides and ellagitannins, were obtained and each was characterized by different techniques. We grouped together the techniques used to characterize these different oak wood groups of polymers: IR, GC, GC-MS, LC-MS, 1H NMR, SEC, MALDI-TOF/MS. This work focuses on the qualitative aspect only. Copyright © 2004 Society of Chemical Industry [source]

A new type of magnification system in free microvascular tissue transfer: Varioscope M5

MICROSURGERY, Issue 6 2007
Ph.D., Stefano Chiummariello M.D.
Free microvascular tissue transfers have become today a key instrument for the surgical treatment of wide loss of tissue. These procedures can provide definitive treatment in a single operation but they are expensive and require specialized practitioners. The operating microscope traditionally has provided this requirement; our study is focusing on the prospect of using a new visual system,Varioscope M5,in the reconstructive microsurgery field. Varioscope M5 (Life Optics, Vienna, Austria) has been employed in 21 microvascular anastomoses, where different free flaps were used in head and neck reconstruction. The necessity to operate in a different department, not provided with an operating microscope, brought along the idea of exploring an alternative procedure to classical visualization systems. Specific advantages such as reduced cost, freedom of movement, autofocus, minimal upkeep, a variable range of magnification from 2× to 9× are some of the reasons that convinced the authors to use this new type of magnification system. Increasing interest in microsurgery magnification highlights the need for further technical development in that field. We consider Varioscope M5 a future mean of anastomotic magnification in most free-tissue transfers with specific characteristics that combine the microscope and loupe philosophies. © 2007 Wiley-Liss, Inc. Microsurgery, 2007. [source]

Solution of the crystallographic phase problem by iterated projections

ACTA CRYSTALLOGRAPHICA SECTION A, Issue 3 2003
Veit Elser
An algorithm for determining crystal structures from diffraction data is described which does not rely on the usual reciprocal-space formulations of atomicity. The new algorithm implements atomicity constraints in real space, as well as intensity constraints in reciprocal space, by projections that restore each constraint with the minimal modification of the scattering density. To recover the true density, the two projections are combined into a single operation, the difference map, which is iterated until the magnitude of the density modification becomes acceptably small. The resulting density, when acted upon by a single additional operation, is by construction a density that satisfies both intensity and atomicity constraints. Numerical experiments have yielded solutions for atomic resolution X-ray data sets with over 400 non-hydrogen atoms, as well as for neutron data, where positivity of the density cannot be invoked. [source]

Biaryls Made Easy: PEPPSI and the Kumada,Tamao,Corriu Reaction

CHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2007
Michael G. Organ Prof.
Abstract An easily employed, highly versatile Kumada,Tamao,Corriu (KTC) protocol utilizing the PEPPSI (Pyridine, Enhanced, Precatalyst, Preparation, Stabilization and Initiation) precatalysts 1 and 2 is detailed. The ease-of-use of these catalysts and the synthesis of a wide range of hindered biaryls, large coupling partners and drug-like heterocycles, in high yield, makes the PEPPSI-KTC protocol very attractive. The high reactivity of the PEPPSI system allowed a tetra- ortho -substituted heterocycle, 11 to be synthesized at room temperature for the first time using any protocol. The PEPPSI protocols also tolerated the Boc protecting group and phenols required no protection in modified conditions. A relatively large scale (10 g) reaction was also performed with no loss in performance. Furthermore, PEPPSI-IPr, 1, was compared to previously reported highly active phosphine ligands 42, 43, and 44 and was shown to result in significantly better yields under identical conditions. Finally, we demonstrated that the PEPPSI catalyst system is very adept at performing sequential KTC coupling reactions, analogous to multicomponent reactions, which allow complex polyaryl and polyheteroaryl architectures to be produced in one single operation. [source]