Zinc(II) Triflate‐Catalyzed Divergent Synthesis of Polyfunctionalized Pyrroles

The zinc(II) triflate‐catalyzed synthesis of highly functionalized pyrroles is described. The sequence involves the preliminary preparation of α‐aminohydrazones by Michael addition of primary amines to 1,2‐diaza‐1,3‐dienes. The treatment of these intermediates with dialkyl acetylenedicarboxylates produces α‐(N‐enamino)‐hydrazones that are converted into the corresponding pyrroles. The substituents on the carbon in position four of 1,2‐diaza‐1,3‐dienes drive the regioselectivity of the ring closure process. Starting from 4‐aminocarbonyl‐1,2‐diaza‐1,3‐dienes only dialkyl 1‐substituted 5‐aminocarbonyl‐1H‐pyrrole‐2,3‐dicarboxylates are achieved by Lewis acid‐catalyzed ring closure. A screening of several Lewis/Brønsted acid catalysts is performed. Zinc(II) triflate is the most efficient catalyst. Under similar reaction conditions, employing 4‐alkoxycarbonyl‐1,2‐diaza‐1,3‐dienes, only 4‐hydroxy‐1H‐pyrrole‐2,3‐dicarboxylates are synthesized. These latter reactions can be accomplished regioselectively also in one pot. Using 4‐aminocarbonyl‐1,2‐diaza‐1,3‐dienes, diamines and dialkyl acetylenedicarboxylates the sequence provides the corresponding α,ω‐di(N‐pyrrolyl)alkanes.     

Growth of carbon nanotube forests on carbon fibers with an amorphous silicon interface

Aligned multi-walled carbon nanotube forests were grown by chemical vapour deposition on carbon fibers by the use of an amorphous Si interface. The Si layer creates a barrier, hindering the Fe catalyst diffusion into the carbon fibers. This method provides a way to tailor the thermal, electrical and mechanical properties of the fiber-resin interface of a polymer composite.     

Glass foam of macroporosity using glass waste and sodium hydroxide as the foaming agent

Glass foams using float glass waste and sodium hydroxide were produced. The influence of the sodium hydroxide amount in the foam formulation was studied. Titanium dioxide was used as a strengthening agent. The variations of temperature, heating rate and sintering time were investigated during the synthesis process. Open porosity was estimated using mercury porosimetry. The morphology of the glass foams was evaluated using scanning electron microscopy, phase formation was studied using X-ray diffraction, and chemical composition was estimated using X-ray fluorescence. As a result, glass foams with macroporosity were obtained. Since the glass foams used glass waste as reactant, the results suggest the development of an alternative route for glass recycling.     

Field Trapping of Tomato Moth, Tuta absoluta with Pheromone Traps

Field evaluations demonstrate that the addition of the minor pheromone component (3E,8Z)-tetradecadien-1-yl acetate to the major component (3E,8Z,11Z)-tetradecatrien-1-yl acetate does not significantly increase the trap catches of Tuta absoluta males in the field. The triene acetate itself is highly attractive, catching about 869 ± 255 males per trap in three consecutive nights. The addition of two isomers of the minor component (3E,8Z)-tetradecadien-1-yl acetate, (3E,11Z)-tetradecadienyl-yl acetate and (8Z,11Z)-tetradecadien-1-yl acetate, to the major component (3E,8Z,11Z)-tetradecatrien-1-yl acetate also did not significantly alter the number of the males caught in the traps.     

A framework for analytical cost estimation of mechanical components based on manufacturing knowledge representation

This paper presents a novel framework for manufacturing and cost-related knowledge formalization. This artefact allows industries to capitalize the knowled     

Tritrichomonas foetus adhere to superhydrophilic vertically aligned multi-walled carbon nanotube surface

For the first time, we show that Tritrichomonas foetus can adhere on superhydrophilic vertically aligned carbon nanotubes (VACNT) films. Scanning electron microscopy shows an unusual adhesion with a higher membrane filopodium projection in all directions, directly attached to superhydrophilic VACNT tips.     

Impact of the introduction of a partogram on maternal and perinatal mortality. Study performed in a maternity clinic in Niameny, Niger

Maternal mortality remains one of the major problems in public health today especially in developing countries where maternal mortality is estimated to be between 500 and 1000 deaths for 100,000 live births. In 1987, the safe motherhood initiative was launched with the objective of reducing maternal mortality by 50% within ten years. One of the methods introduced to reduce the high incidence of maternal and neonatal mortality in developing countries, is the partogram, a visual means used in evaluating a normal delivery. It acts as an early warning system, allowing for the early detection of abnormal evolution in labour as well for the mother as for the foetus. This instrument was introduced in all the maternity wards in Niger in 1990 by the Ministry of Public Health. A study was conducted in one of the maternities of the capital to ascertain the effectiveness of this new instrument to both the mother during labor and the newborn child. 1299 women in labor, primi-and multiparous, participated in the study. Two groups were formed: one consisted of women that delivered prior to the introduction of the partogram, the second group was comprised of women who delivered after its introduction. The results of this study have shown that the introduction of the partogram: reduces the amount of time that a women is in labor, improves the follow-up care the pregnant woman receives, results in a more timely decision made by the health official, and consequently, a prompt referral to a specialised center. The authors estimate that, if used correctly, the introduction of this instrument can have along with other appropriate measures, a considerable impact in the reduction of maternal and neonatal mortality.     

A measure of dignified treatment for healthcare workers: design and psychometric properties

Behaviormetrika - Despite the importance of both user and healthcare worker considerations to the achievement of a comprehensive understanding of dignified care in organizations, most studies in...