Induction of triacylglycerol production in Chlamydomonas reinhardtii: Comparative analysis of different element regimes

Cataloged from PDF version of article.In this study, impacts of different element absence (nitrogen, sulfur, phosphorus and magnesium) and supplementation (nitrogen and zinc) on element uptake and triacylglycerol production was followed in wild type Chlamydomonas reinhardtii CC-124 strain. Macro- and microelement composition of C. reinhardtii greatly differed under element regimes studied. In particular, heavy metal quotas of the microalgae increased strikingly under zinc supplementation. Growth was suppressed, cell biovolume, carbohydrate, total neutral lipid and triacylglycerol levels increased when microalgae were incubated under these element regimes. Most of the intracellular space was occupied by lipid bodies under all nutrient starvations, as observed by confocal microscopy and transmission electron micrographs. Results suggest that sulfur, magnesium and phosphorus deprivations are superior to nitrogen deprivation for the induction triacylglycerol production in C. reinhardtii. On the other hand, FAME profiles of the nitrogen, sulfur and phosphorus deprived cells were found to meet the requirements of international standards for biodiesel. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved

Nitrogen and sulfur deprivation differentiate lipid accumulation targets of Chlamydomonas reinhardtii

Cataloged from PDF version of article.Nitrogen (N) and sulfur (S) have inter-related and distinct impacts on microalgal metabolism; with N starvation having previously been reported to induce elevated levels of the biodiesel feedstock material triacylglycerol (TAG), while S deprivation is extensively studied for its effects on biohydrogen production in microalgae.1,2 We have previously demonstrated that N- and S-starved cells of Chlamydomonas reinhardtii display different metabolic trends, suggesting that different response mechanisms exist to compensate for the absence of those two elements.3 We used C. reinhardtii CC-124 mt(-) and CC-125 mt(+) strains to test possible metabolic changes related to TAG accumulation in response to N and S deprivation, considering that gamete differentiation in this organism is mainly regulated by N.4 Our findings contribute to the understanding of microalgal response to element deprivation and potential use of element deprivation for biodiesel feedstock production using microalgae, but much remains to be elucidated on the precise contribution of both N and S starvation on microalgal metabolism. © 2012 Landes Bioscience

PEGylated calix[4]arene as a carrier for a Bodipy-based photosensitizer

Cataloged from PDF version of article.Heavy atom substituted Bodipy compounds, unlike the parent chromophore, undergo rapid intersystem crossing to generate singlet oxygen, which is the primary cytotoxic agent exploited in PDT. In this work, we show that an organic soluble calix[4]arene can be functionalized by Knoevenagel reaction and then converted into an amphiphilic photosensitizer in a few steps. In addition to generating a potentially useful photosensitizer, the sequence of reactions is the first use of a Bodipy dye as a chromophoric/fluorogenic label without the typical reactive functional groups. 2013 Elsevier Ltd. All rights reserved

Like a fish in water: Habitus adaptation mechanisms of informal tourism entrepreneurs in Thailand.

This article investigates possible pathways of habitus change by informal tourism entrepreneurs in Thailand. Bourdieu's concept of habitus is depicted as a person's understanding of the world. Do people adapt their worldview in response to only external stimuli? Through ethnographic fieldwork including participant observations and active semi-structured interviews with 53 participants, this paper identifies a classification of four modes of habitus adaptation: (1) Understanding and appreciating the field and its conditions, (2) Challenging core beliefs systems, (3) Applying a practical sense to ‘objective possibilities’, and, (4) Challenging non-reflective dispositions. We argue that charting the modes of habitus adaptation could help policymakers understand the change processes of informal entrepreneurs in the tourism sector and their willingness to change.</p

Vibration and noise characteristics of hook type olive harvesters

The objective of this study was to obtain and evaluate the vibration and noise characteristics of portable hook type mechanical olive harvesters. Experiments included five hook type olive harvesters. In this study, the vibration and sound pressure levels of different harvesters were measured at idling and full load condition. The vibration levels on the handle grip of harvesters were measured and analyzed for both operator’s right and left hand, respectively. The sound pressure level was measured at ear level of the operator. The frequency weighting acceleration was calculated. The vibration total value was expressed as the root-mean-square (rms) of three component values. The acceleration values vary between 5.52 and 39.15 ms-2 for right hand and 4.18 and 61.01 ms-2 for left hand. The equivalent noise pressure levels of the harvesters were measured between 91 and 103 dB (A) in the full loading conditions and between 67 and 80 dB (A) idling working conditions.Key words: Olive harvester, vibration, noise, ha

Theoretical study of isolated dangling bonds, dangling bond wires and dangling bond clusters on H:Si(100)-(2×\times1) surface

We theoretically study the electronic band structure of isolated unpaired and paired dangling bonds (DB), DB wires and DB clusters on H:Si(100)-(2$\times$1) surface using Extended H\"uckel Theory (EHT) and report their effect on the Si band gap. An isolated unpaired DB introduces a near-midgap state, whereas a paired DB leads to $\pi$ and $\pi^*$ states, similar to those introduced by an unpassivated asymmetric dimer (AD) Si(100)-(2$\times$1) surface. Such induced states have very small dispersion due to their isolation from the other states, which reside in conduction and valence band. On the other hand, the surface state induced due to an unpaired DB wire in the direction along the dimer row (referred to as $[\bar{1}10]$), has large dispersion due to the strong coupling between the adjacent DBs, being 3.84$\AA$ apart. However, in the direction perpendicular to the dimer row (referred to as [110]), due to the reduced coupling between the DBs being 7.68$\AA$ apart, the dispersion in the surface state is similar to that of an isolated unpaired DB. Apart from this, a paired DB wire in $[\bar{1}10]$ direction introduces $\pi$ and $\pi^*$ states similar to those of an AD surface and a paired DB wire in [110] direction exhibits surface states similar to those of an isolated paired DB, as expected. Besides this, we report the electronic structure of different DB clusters, which exhibit states inside the band gap that can be interpreted as superpositions of states due to unpaired and paired DBs.Comment: 7 pages, 10 figure, 1 tabl

Clutch transient heat transfer simulation for hill start vehicle test condition

The successive repetitive engagement operation causes temperature rise on the friction surfaces of the automotive dry clutches. This condition is simulated via hill start vehicle tests by clutch manufacturers during thermal performance validation of new transmission platforms or vehicle configurations. The aim of this study is to determine the temperature variation of the clutch pressure plate by the use of a 1D transient thermal simulation for the hill start vehicle test conditions. Simulation model includes pressure plate, flywheel and clutch housing elements. Clutch housing air temperature variation was simulated numerically for 120 successive repetitive cycles of hill start truck vehicle test. Parameters effecting pressure plate temperature change were analyzed. It is observed that increasing the mass of the clutch pressure plate results a decrease in the temperature variation in early stages of engagement cycles. However, increasing the value of the pressure plate convection coefficient significantly reduces the temperature variation during all stages of cycles. Finally, lightweight design proposals of dry clutch pressure plate for better energy dissipation are demonstrated.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers

Near-IR-Triggered, Remote-Controlled Release of Metal Ions: A Novel Strategy for Caged Ions

Cataloged from PDF version of article.A ligand incorporating a dithioethenyl moiety is cleaved into fragments which have a lower metal-ion affinity upon irradiation with low-energy red/near-IR light. The cleavage is a result of singlet oxygen generation which occurs on excitation of the photosensitizer modules. The method has many tunable factors that could make it a satisfactory caging strategy for metal ions