The catabolic capacity of Saccharomyces cerevisiae is preserved to a higher extent during carbon compared to nitrogen starvation.

A comparison of catabolic capacity was made between S. cerevisiae cells subjected to 24 h carbon or nitrogen starvation. The cells were shifted to starvation conditions at the onset of respiratory growth on ethanol in aerobic batch cultures, using glucose as the carbon and energy source. The results showed that the catabolic capacity was preserved to a much larger extent during carbon compared to nitrogen starvation. Nitrogen starvation experiments were made in the presence of ethanol (not glucose) to exclude the effect of glucose transport inactivation (Busturia and Lagunas, 1986). Hence, the difference in catabolic capacity could not be attributed to differences in glucose transport capacity during these conditions. In order to understand the reason for this difference in starvation response, measurement of protein composition, adenine nucleotides, inorganic phosphate, polyphosphate and storage carbohydrates were performed. No clear correlation between any of these variables and catabolic capacity after starvation could be obtained. However, there was a positive correlation between total catabolic activity and intracellular ATP concentration when glucose was added to starved cells. The possible mechanism for this correlation, as well as what determines the ATP level, is discussed.     

Non-intrusive headspace gas measurements by laser spectroscopy – Performance validation by a reference sensor

The oxygen concentration in the headspace of a large number of liquid food containers is assessed with non-intrusive diode laser absorption spectroscopy. The results are compared to those given by a traditional intrusive measurement method. The upper portions of the containers are made of translucent but non-transparent plastic materials, through which the laser light is diffusively transmitted. Measurements are performed both on packages with modified atmosphere and with normal air conditions. It is concluded that the novel non-intrusive technique provides oxygen concentrations that generally differ by less than one percentage point from the reference sensor values.     

Corrosion of carbon steel underneath a lead/potassium chloride salt mixture

High amounts of lead in waste/recycled wood fuel are known to be a contributing factor to the increased corrosion often related to this type of fuel. In combination with potassium, usually present in the fuel, low‐melting point salt mixtures between lead chloride (PbCl ₂) and potassium chloride (KCl) are expected to form. The purpose of this study is to investigate reactions in the mixed salt of PbCl ₂ and KCl and its interactions with carbon steel P265GH and its oxide. Laboratory exposures were performed in an isothermal tube furnace with a salt mixture of PbCl ₂/KCl (50/50 mol%) put on steel samples. The test duration was 24 hr at either 300°C or 340°C in an atmosphere of 100 ppm HCl and 20 vol% H ₂O in synthetic air. After exposure, the salt mixture consists of distinct areas of KCl and PbCl ₂ but also the compounds K ₂PbCl ₄ and KPb ₂Cl ₅. A general observation is that the oxide thickness increases with temperature and that areas with Pb/K‐mixed salt are frequently found in close connection to more corroded areas. Often the more lead‐rich phase KPb ₂Cl ₅ is located closest to the corrosion product indicating its importance for the corrosion.     

Metallopolymer Organohydrogels with Photo-Controlled Coordination Crosslinks Work Properly Below 0 °C

Controlling the structures and functions of gels is important for both fundamental research and technological applications. Introducing photoresponsive units into gels enables remote control of their properties with light. However, existing gels show photoresponsiveness only at room temperature or elevated temperatures. The development of photoresponsive gels that work below 0 °C can expand their usage in cold environments. Here, photoresponsive metallopolymer organohydrogels that function even at −20 °C are reported. The organohydrogels are prepared using photoresponsive Ru–thioether coordination bonds as reversible crosslinks to form polymer networks. A water/glycerol mixture is used as an anti-freezing solvent. At −20 °C, the Ru–thioether coordination bonds are dissociated under light irradiation and reformed reversibly in the dark, which result in alternating crosslinking densities in the polymer networks. This process enables inducing reversible gel-to-sol transitions, healing damaged gels, controlling the mechanical properties and volumes of the gels, and rewriting microstructures on the gels below 0 °C.     

Second Stage of Upper Bainite in a 0.3 Mass Pct C Steel

Upper bainite forms in at least two stages, the formation of parallel plates of ferrite and the transformation of the interspaces to a mixture of cementite and ferrite. The first stage was examined in a preceding metallographic study of the formation of ferrite in hypoeutectoid steels and the second stage, which is initiated by the occurrence of cementite in the interspaces, is the subject of the present study. The alloy from the preceding study will also be used here. The band of austenite in the interspaces between parallel plates is generally transformed by a degenerate eutectoid transformation when this band is thin. When it is thicker, it will transform by a more cooperative growth mechanism and result in a eutectoid colony, often with cementite platelets. A series of sketches are presented which illustrate in detail how the second stage of upper bainite progresses according to the present observations. The cooperative manner did not increase as the temperature was lowered because the tendency to form plates of ferrite was still increasing at lower temperatures, making the interspaces too narrow for the cooperative reaction to dominate over the formation of fine plates of ferrite.

     

Pulmonary exposure to single-walled carbon nanotubes does not affect the early immune response against Toxoplasma gondii

ABSTRACT: BACKGROUND: Single-walled carbon nanotubes (SWCNT) trigger pronounced inflammation and fibrosis in the lungs of mice following administration via pharyngeal aspiration or inhalation. Human exposure to SWCNT in an occupational setting may occur in conjunction with infections and this could yield enhanced or suppressed responses to the offending agent. Here, we studied whether the sequential exposure to SWCNT via pharyngeal aspiration and infection of mice with the ubiquitous intracellular parasite Toxoplasma gondii would impact on the immune response of the host against the parasite. METHODS: C57BL/6 mice were pre-exposed by pharyngeal administration of SWCNT (80 + 80 mug/mouse) for two consecutive days followed by intravenous injection with either 1x103 or 1x104 green fluorescence protein and luciferase-expressing T. gondii tachyzoites. The dissemination of T. gondii was monitored by in vivo bioluminescence imaging in real time for 7 days and by plaque formation. The inflammatory response was analysed in bronchoalveolar lavage (BAL) fluid, and by assessment of morphological changes and immune responses in lung and spleen. RESULTS: There were no differences in parasite distribution between mice only inoculated with T. gondii or those mice pre-exposed for 2 days to SWCNT before parasite inoculum. Lung and spleen histology and inflammation markers in BAL fluid reflected the effects of SWCNT exposure and T. gondii injection, respectively. We also noted that CD11c positive dendritic cells but not F4/80 positive macrophages retained SWCNT in the lungs 9 days after pharyngeal aspiration. However, co-localization of T. gondii with CD11c or F4/80 positive cells could not be observed in lungs or spleen. Pre-exposure to SWCNT did not affect the splenocyte response to T. gondii. CONCLUSIONS: Taken together, our data indicate that pre-exposure to SWCNT does not enhance or suppress the early immune response to T. gondii in mice.     

Process development for the assembly of microsystems with hot melt adhesives

In the assembly of microsystems, a reliable, precise, and fast joining process remains an open challenge. An approach using hot melt adhesives to join these micro parts is investigated within this article. A relevant issue with hot melt adhesives is introducing heat into the assembly process. This heat management can be achieved using either an active or passive concept. These concepts and their influence on process design are discussed. The realization of active heat management within a gripper is discussed in detail. Experimental results from an exemplary process show the applicability of the hybrid assembly process using hot melt adhesives.     

Coping with anger-provoking situations, psychosocial working conditions, and ECG-detected signs of coronary heart disease.

This study explored the association among coping, psychosocial work factors, and signs of coronary heart disease (CHD) among prison staff (777 men, 345 women). Electrocardiogram (ECG) recordings at rest, health examinations, and a questionnaire were used. A high level of covert coping in men and a low level of open coping in women showed the strongest association with signs of CHD. Among several traditional biological and lifestyle risk factors, only age and systolic blood pressure in men and none in the case of women were significantly associated with CHD signs in the final multivariate regression analyses. A coping style of repressed emotions and actions in anger-provoking situations, independent of traditional risk factors, seems to be associated with a prevalence of ECG signs in male and female prison staff. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Metallographic evidence of carbon diffusion in the growth of bainite

There are two paradigms regarding the formation of bainite. One is based on the first stage being rapid, diffusionless growth of acicular ferrite and the subsequent formation of carbide occurring by precipitation from the supersaturated ferrite. An assumption that the first stage occurs as a series of subsequent rapid steps resulting in sub-units plays an important role as an explanation of the not so rapid growth observed macroscopically. The other paradigm is based on the first stage being the formation of acicular ferrite under carbon diffusion and on the subsequent growth of carbide and ferrite side by side. Metallographic observations are presented that support the second paradigm. It is difficult to see how they can be accounted for by the first paradigm, in particular the observation of the shapes of sub-units.